Author name code: appourchaux ADS astronomy entries on 2022-09-14 author:"Appourchaux, Thierry" ------------------------------------------------------------------------ Title: Solar-like oscillations and ellipsoidal variations in TESS observations of the binary 12 Boötis Authors: Ball, Warrick H.; Miglio, Andrea; Chaplin, William J.; Stassun, Keivan G.; García, Rafael; González-Cuesta, Lucia; Mathur, Savita; Appourchaux, Thierry; Benomar, Othman; Buzasi, Derek L.; Jiang, Chen; Kayhan, Cenk; Örtel, Sibel; Orhan, Zeynep Çelik; Yıldız, Mutlu; Ong, J. M. Joel; Basu, Sarbani Bibcode: 2022MNRAS.tmp.2121B Altcode: 2022arXiv220802302B Binary stars in which oscillations can be studied in either or both components can provide powerful constraints on our understanding of stellar physics. The bright binary 12 Boötis (12 Boo) is a particularly promising system because the primary is roughly 60 per cent brighter than the secondary despite being only a few per cent more massive. Both stars have substantial surface convection zones and are therefore, presumably, solar-like oscillators. We report here the first detection of solar-like oscillations and ellipsoidal variations in the TESS light curve of 12 Boo. Though the solar-like oscillations are not clear enough to unambiguously measure individual mode frequencies, we combine global asteroseismic parameters and a precise fit to the spectral energy distribution (SED) to provide new constraints on the properties of the system that are several times more precise than values in the literature. The SED fit alone provides new effective temperatures, luminosities and radii of 6115 ± 45 K, 7.531 ± 0.110 L⊙ and 2.450 ± 0.045 R⊙ for 12 Boo A and 6200 ± 60 K, 4.692 ± 0.095 L⊙ and 1.901 ± 0.045 R⊙ for 12 Boo B. When combined with our asteroseismic constraints on 12 Boo A, we obtain an age of $2.67^{+0.12}_{-0.16}\, \mathrm{Gyr}$, which is consistent with that of 12 Boo B. Title: The on-ground data reduction and calibration pipeline for SO/PHI-HRT Authors: Sinjan, J.; Calchetti, D.; Hirzberger, J.; Orozco Suárez, D.; Albert, K.; Albelo Jorge, N.; Appourchaux, T.; Alvarez-Herrero, A.; Blanco Rodríguez, J.; Gandorfer, A.; Germerott, D.; Guerrero, L.; Gutierrez Marquez, P.; Kahil, F.; Kolleck, M.; Solanki, S. K.; del Toro Iniesta, J. C.; Volkmer, R.; Woch, J.; Fiethe, B.; Gómez Cama, J. M.; Pérez-Grande, I.; Sanchis Kilders, E.; Balaguer Jiménez, M.; Bellot Rubio, L. R.; Carmona, M.; Deutsch, W.; Fernandez-Rico, G.; Fernández-Medina, A.; García Parejo, P.; Gasent Blesa, J. L.; Gizon, L.; Grauf, B.; Heerlein, K.; Korpi-Lagg, A.; Lange, T.; López Jiménez, A.; Maue, T.; Meller, R.; Michalik, H.; Moreno Vacas, A.; Müller, R.; Nakai, E.; Schmidt, W.; Schou, J.; Schühle, U.; Staub, J.; Strecker, H.; Torralbo, I.; Valori, G. Bibcode: 2022arXiv220814904S Altcode: The ESA/NASA Solar Orbiter space mission has been successfully launched in February 2020. Onboard is the Polarimetric and Helioseismic Imager (SO/PHI), which has two telescopes, a High Resolution Telescope (HRT) and the Full Disc Telescope (FDT). The instrument is designed to infer the photospheric magnetic field and line-of-sight velocity through differential imaging of the polarised light emitted by the Sun. It calculates the full Stokes vector at 6 wavelength positions at the Fe I 617.3 nm absorption line. Due to telemetry constraints, the instrument nominally processes these Stokes profiles onboard, however when telemetry is available, the raw images are downlinked and reduced on ground. Here the architecture of the on-ground pipeline for HRT is presented, which also offers additional corrections not currently available on board the instrument. The pipeline can reduce raw images to the full Stokes vector with a polarimetric sensitivity of $10^{-3}\cdot I_{c}$ or better. Title: The magnetic drivers of campfires seen by the Polarimetric and Helioseismic Imager (PHI) on Solar Orbiter Authors: Kahil, F.; Hirzberger, J.; Solanki, S. K.; Chitta, L. P.; Peter, H.; Auchère, F.; Sinjan, J.; Orozco Suárez, D.; Albert, K.; Albelo Jorge, N.; Appourchaux, T.; Alvarez-Herrero, A.; Blanco Rodríguez, J.; Gandorfer, A.; Germerott, D.; Guerrero, L.; Gutiérrez Márquez, P.; Kolleck, M.; del Toro Iniesta, J. C.; Volkmer, R.; Woch, J.; Fiethe, B.; Gómez Cama, J. M.; Pérez-Grande, I.; Sanchis Kilders, E.; Balaguer Jiménez, M.; Bellot Rubio, L. R.; Calchetti, D.; Carmona, M.; Deutsch, W.; Fernández-Rico, G.; Fernández-Medina, A.; García Parejo, P.; Gasent-Blesa, J. L.; Gizon, L.; Grauf, B.; Heerlein, K.; Lagg, A.; Lange, T.; López Jiménez, A.; Maue, T.; Meller, R.; Michalik, H.; Moreno Vacas, A.; Müller, R.; Nakai, E.; Schmidt, W.; Schou, J.; Schühle, U.; Staub, J.; Strecker, H.; Torralbo, I.; Valori, G.; Aznar Cuadrado, R.; Teriaca, L.; Berghmans, D.; Verbeeck, C.; Kraaikamp, E.; Gissot, S. Bibcode: 2022A&A...660A.143K Altcode: 2022arXiv220213859K Context. The Extreme Ultraviolet Imager (EUI) on board the Solar Orbiter (SO) spacecraft observed small extreme ultraviolet (EUV) bursts, termed campfires, that have been proposed to be brightenings near the apexes of low-lying loops in the quiet-Sun atmosphere. The underlying magnetic processes driving these campfires are not understood.
Aims: During the cruise phase of SO and at a distance of 0.523 AU from the Sun, the Polarimetric and Helioseismic Imager on Solar Orbiter (SO/PHI) observed a quiet-Sun region jointly with SO/EUI, offering the possibility to investigate the surface magnetic field dynamics underlying campfires at a spatial resolution of about 380 km.
Methods: We used co-spatial and co-temporal data of the quiet-Sun network at disc centre acquired with the High Resolution Imager of SO/EUI at 17.4 nm (HRIEUV, cadence 2 s) and the High Resolution Telescope of SO/PHI at 617.3 nm (HRT, cadence 2.5 min). Campfires that are within the SO/PHI−SO/EUI common field of view were isolated and categorised according to the underlying magnetic activity.
Results: In 71% of the 38 isolated events, campfires are confined between bipolar magnetic features, which seem to exhibit signatures of magnetic flux cancellation. The flux cancellation occurs either between the two main footpoints, or between one of the footpoints of the loop housing the campfire and a nearby opposite polarity patch. In one particularly clear-cut case, we detected the emergence of a small-scale magnetic loop in the internetwork followed soon afterwards by a campfire brightening adjacent to the location of the linear polarisation signal in the photosphere, that is to say near where the apex of the emerging loop lays. The rest of the events were observed over small scattered magnetic features, which could not be identified as magnetic footpoints of the campfire hosting loops.
Conclusions: The majority of campfires could be driven by magnetic reconnection triggered at the footpoints, similar to the physical processes occurring in the burst-like EUV events discussed in the literature. About a quarter of all analysed campfires, however, are not associated to such magnetic activity in the photosphere, which implies that other heating mechanisms are energising these small-scale EUV brightenings. Title: PLATO Performance Authors: Cabrera, J.; Rauer, H.; Börner, A.; Grießbach, D.; Paproth, C.; Samadi, R.; Appourchaux, T. Bibcode: 2021plat.confE..95C Altcode: The PLATO mission (PLAnetary Transits and Oscillations of stars, hereafter abbreviated as PLATO) has been selected as part of ESA's Cosmic Vision 2015-2025 program for the M3 mission launch foreseen in 2026. The main science goal of PLATO is to detect and characterize extrasolar planets, including terrestrial planets in the habitable zone (HZ) of their host stars. Characterization here means to derive accurate planetary radii, masses, and ages. In order to achieve these goals, it is mandatory to characterize the host stars. As transit search is an indirect detection and characterization method, the accurate knowledge of the host star parameters limits the accuracy of the derived planet parameters. PLATO will therefore monitor hundreds of thousands of stars for up to three years in order to fully characterize stars with asteroseismology and to detect transiting planets. The resulting large data set of stellar light curves provides an additional science return of the mission that reaches far beyond the exoplanet science case into stellar, Galactic, and extragalactic research.

PLATO Payload features a multi-telescope configuration consisting of 26 cameras, of 12 cm pupil size aperture each, covering a field of view of about 2000 square degrees spread over 104 CCDs of 20 million pixels a piece. PLATO has strict noise requirements achieved through excellent optics transmission and quantum efficiency, low read-out noise, and stringent pointing requirements.

In this talk we will review the drivers for PLATO Performance and present the most recent description of the status of noise budget and verification of main performance requirements (including field of view and pointing performance). Title: A journey of exploration to the polar regions of a star: probing the solar poles and the heliosphere from high helio-latitude Authors: Harra, Louise; Andretta, Vincenzo; Appourchaux, Thierry; Baudin, Frédéric; Bellot-Rubio, Luis; Birch, Aaron C.; Boumier, Patrick; Cameron, Robert H.; Carlsson, Matts; Corbard, Thierry; Davies, Jackie; Fazakerley, Andrew; Fineschi, Silvano; Finsterle, Wolfgang; Gizon, Laurent; Harrison, Richard; Hassler, Donald M.; Leibacher, John; Liewer, Paulett; Macdonald, Malcolm; Maksimovic, Milan; Murphy, Neil; Naletto, Giampiero; Nigro, Giuseppina; Owen, Christopher; Martínez-Pillet, Valentín; Rochus, Pierre; Romoli, Marco; Sekii, Takashi; Spadaro, Daniele; Veronig, Astrid; Schmutz, W. Bibcode: 2021ExA...tmp...93H Altcode: 2021arXiv210410876H A mission to view the solar poles from high helio-latitudes (above 60°) will build on the experience of Solar Orbiter as well as a long heritage of successful solar missions and instrumentation (e.g. SOHO Domingo et al. (Solar Phys. 162(1-2), 1-37 1995), STEREO Howard et al. (Space Sci. Rev. 136(1-4), 67-115 2008), Hinode Kosugi et al. (Solar Phys. 243(1), 3-17 2007), Pesnell et al. Solar Phys. 275(1-2), 3-15 2012), but will focus for the first time on the solar poles, enabling scientific investigations that cannot be done by any other mission. One of the major mysteries of the Sun is the solar cycle. The activity cycle of the Sun drives the structure and behaviour of the heliosphere and of course, the driver of space weather. In addition, solar activity and variability provides fluctuating input into the Earth climate models, and these same physical processes are applicable to stellar systems hosting exoplanets. One of the main obstructions to understanding the solar cycle, and hence all solar activity, is our current lack of understanding of the polar regions. In this White Paper, submitted to the European Space Agency in response to the Voyage 2050 call, we describe a mission concept that aims to address this fundamental issue. In parallel, we recognise that viewing the Sun from above the polar regions enables further scientific advantages, beyond those related to the solar cycle, such as unique and powerful studies of coronal mass ejection processes, from a global perspective, and studies of coronal structure and activity in polar regions. Not only will these provide important scientific advances for fundamental stellar physics research, they will feed into our understanding of impacts on the Earth and other planets' space environment. Title: Amplitude of solar gravity modes generated by penetrative plumes Authors: Pinçon, C.; Appourchaux, T.; Buldgen, G. Bibcode: 2021A&A...650A..47P Altcode: 2021arXiv210303760P Context. The observation of gravity modes is expected to give us unprecedented insights into the inner dynamics of the Sun. Nevertheless, there is currently no consensus on their detection. Within this framework, predicting their amplitudes is essential to guide future observational strategies and seismic studies.
Aims: While previous estimates considered convective turbulent eddies as the driving mechanism, our aim is to predict the amplitude of low-frequency asymptotic gravity modes generated by penetrative convection at the top of the radiative zone.
Methods: A generation model previously developed for progressive gravity waves was adapted to the case of resonant gravity modes. The stellar oscillation equations were analyzed considering the plume ram pressure at the top of the radiative zone as the forcing term. The plume velocity field was modeled in an analytical form.
Results: We obtain an analytical expression for the mode energy. It is found to depend critically on the time evolution of the plumes inside the generation region. Using a solar model, we then compute the apparent surface radial velocity of low-degree gravity modes as would be measured by the GOLF instrument, in the frequency range 10 µHz ≤ ν ≤ 100 µHz. In the case of a Gaussian plume time evolution, gravity modes turn out to be undetectable because of too small surface amplitudes. This holds true despite a wide range of values considered for the parameters of the model. In the other limiting case of an exponential time evolution, plumes are expected to drive gravity modes in a much more efficient way because of a much higher temporal coupling between the plumes and the modes than in the Gaussian case. Using reasonable values for the plume parameters based on semi-analytical models, the apparent surface velocities in this case are one order of magnitude lower than the 22-year GOLF detection threshold and lower than the previous estimates considering turbulent pressure as the driving mechanism, with a maximum value of 0.05 cm s−1 for ℓ = 1 and ν ≈ 100 µHz. When accounting for uncertainties on the plume parameters, the apparent surface velocities in the most favorable plausible case become comparable to those predicted with turbulent pressure, and the GOLF observation time required for a detection at ν ≈ 100 µHz and ℓ = 1 is reduced to about 50 yr.
Conclusions: Penetrative convection can drive gravity modes in the most favorable plausible case as efficiently as turbulent pressure, with amplitudes slightly below the current detection threshold. When detected in the future, the measurement of their amplitudes is expected to provide information on the plume dynamics at the base of the convective zone. In order to make a proper interpretation, this potential nevertheless requires further theoretical improvements in our description of penetrative plumes. Title: Characteristics and performances of an interferometric Doppler imager installed at the 188 cm telescope of Okayama Observatory Authors: Schmider, François-Xavier; Dejonghe, Julien; Guillot, Tristan; Ikoma, Masahiro; Boumier, Patrick; Sato, Bun'ei; Jackiewicz, Jason; Izumiura, Hideyuki; Hanayama, Hidekazu; Abe, Lyu; Gonçalves, Ivan; Gouvret, Carole; Fantéï-Caujolle, Yan; Morand, Frédéric; Preis, Olivier; Rivet, Jean-Pierre; Appourchaux, Thierry; Leclec'h, Jean-Christophe; Ballans, Hervé; Langlet, François; Baudin, Frédéric; Aoyama, Yuhiko; Kawaushi, Kiyoe; Horiuchi, Takashi; Gaulme, Patrick; Voelz, David; Underwood, Thomas Bibcode: 2020SPIE11447E..3DS Altcode: We describe the performances of a novel Doppler imager, aimed to detect acoustic oscillations and atmospheric dynamics at the surface of giant planets of the Solar System in the frame of the JOVIAL (Jovian Oscillations detection by Velocity Imaging At several Longitudes) project. The first JOVIAL instrument was installed on the 188cm telescope at Okayama branch of National Astronomical Observatory of Japan (NAOJ) in April 2019. This instrument is a part of a ground based network of three identical instruments installed on telescopes around the world for continuous observations. First observations of Jupiter with the JOVIAL instrument were achieved in June 2019. We describe the instrument principle, its design and the set-up at Okayama observatory, as well as the performances reached during the first observing run. We finally provide plans for future observations with the network. Title: A Journey of Exploration to the Polar Regions of a Star: Probing the Solar Poles and the Heliosphere from High Helio-Latitude Authors: Finsterle, W.; Harra, L.; Andretta, V.; Appourchaux, T.; Baudin, F.; Bellot Rubio, L.; Birch, A.; Boumier, P.; Cameron, R. H.; Carlsson, M.; Corbard, T.; Davies, J. A.; Fazakerley, A. N.; Fineschi, S.; Gizon, L. C.; Harrison, R. A.; Hassler, D.; Leibacher, J. W.; Liewer, P. C.; Macdonald, M.; Maksimovic, M.; Murphy, N.; Naletto, G.; Nigro, G.; Owen, C. J.; Martinez-Pillet, V.; Rochus, P. L.; Romoli, M.; Sekii, T.; Spadaro, D.; Veronig, A. Bibcode: 2020AGUFMSH0110005F Altcode: A mission to view the solar poles from high helio-latitudes (above 60°) will build on the experience of Solar Orbiter as well as a long heritage of successful solar missions and instrumentation (e.g. SOHO, STEREO, Hinode, SDO), but will focus for the first time on the solar poles, enabling scientific investigations that cannot be done by any other mission. One of the major mysteries of the Sun is the solar cycle. The activity cycle of the Sun drives the structure and behaviour of the heliosphere and is, of course, the driver of space weather. In addition, solar activity and variability provides fluctuating input into the Earth climate models, and these same physical processes are applicable to stellar systems hosting exoplanets. One of the main obstructions to understanding the solar cycle, and hence all solar activity, is our current lack of understanding of the polar regions. We describe a mission concept that aims to address this fundamental issue. In parallel, we recognise that viewing the Sun from above the polar regions enables further scientific advantages, beyond those related to the solar cycle, such as unique and powerful studies of coronal mass ejection processes, from a global perspective, and studies of coronal structure and activity in polar regions. Not only will these provide important scientific advances for fundamental stellar physics research, they will feed into our understanding of impacts on the Earth and other planets' space environment. Title: The Solar Orbiter Science Activity Plan. Translating solar and heliospheric physics questions into action Authors: Zouganelis, I.; De Groof, A.; Walsh, A. P.; Williams, D. R.; Müller, D.; St Cyr, O. C.; Auchère, F.; Berghmans, D.; Fludra, A.; Horbury, T. S.; Howard, R. A.; Krucker, S.; Maksimovic, M.; Owen, C. J.; Rodríguez-Pacheco, J.; Romoli, M.; Solanki, S. K.; Watson, C.; Sanchez, L.; Lefort, J.; Osuna, P.; Gilbert, H. R.; Nieves-Chinchilla, T.; Abbo, L.; Alexandrova, O.; Anastasiadis, A.; Andretta, V.; Antonucci, E.; Appourchaux, T.; Aran, A.; Arge, C. N.; Aulanier, G.; Baker, D.; Bale, S. D.; Battaglia, M.; Bellot Rubio, L.; Bemporad, A.; Berthomier, M.; Bocchialini, K.; Bonnin, X.; Brun, A. S.; Bruno, R.; Buchlin, E.; Büchner, J.; Bucik, R.; Carcaboso, F.; Carr, R.; Carrasco-Blázquez, I.; Cecconi, B.; Cernuda Cangas, I.; Chen, C. H. K.; Chitta, L. P.; Chust, T.; Dalmasse, K.; D'Amicis, R.; Da Deppo, V.; De Marco, R.; Dolei, S.; Dolla, L.; Dudok de Wit, T.; van Driel-Gesztelyi, L.; Eastwood, J. P.; Espinosa Lara, F.; Etesi, L.; Fedorov, A.; Félix-Redondo, F.; Fineschi, S.; Fleck, B.; Fontaine, D.; Fox, N. J.; Gandorfer, A.; Génot, V.; Georgoulis, M. K.; Gissot, S.; Giunta, A.; Gizon, L.; Gómez-Herrero, R.; Gontikakis, C.; Graham, G.; Green, L.; Grundy, T.; Haberreiter, M.; Harra, L. K.; Hassler, D. M.; Hirzberger, J.; Ho, G. C.; Hurford, G.; Innes, D.; Issautier, K.; James, A. W.; Janitzek, N.; Janvier, M.; Jeffrey, N.; Jenkins, J.; Khotyaintsev, Y.; Klein, K. -L.; Kontar, E. P.; Kontogiannis, I.; Krafft, C.; Krasnoselskikh, V.; Kretzschmar, M.; Labrosse, N.; Lagg, A.; Landini, F.; Lavraud, B.; Leon, I.; Lepri, S. T.; Lewis, G. R.; Liewer, P.; Linker, J.; Livi, S.; Long, D. M.; Louarn, P.; Malandraki, O.; Maloney, S.; Martinez-Pillet, V.; Martinovic, M.; Masson, A.; Matthews, S.; Matteini, L.; Meyer-Vernet, N.; Moraitis, K.; Morton, R. J.; Musset, S.; Nicolaou, G.; Nindos, A.; O'Brien, H.; Orozco Suarez, D.; Owens, M.; Pancrazzi, M.; Papaioannou, A.; Parenti, S.; Pariat, E.; Patsourakos, S.; Perrone, D.; Peter, H.; Pinto, R. F.; Plainaki, C.; Plettemeier, D.; Plunkett, S. P.; Raines, J. M.; Raouafi, N.; Reid, H.; Retino, A.; Rezeau, L.; Rochus, P.; Rodriguez, L.; Rodriguez-Garcia, L.; Roth, M.; Rouillard, A. P.; Sahraoui, F.; Sasso, C.; Schou, J.; Schühle, U.; Sorriso-Valvo, L.; Soucek, J.; Spadaro, D.; Stangalini, M.; Stansby, D.; Steller, M.; Strugarek, A.; Štverák, Š.; Susino, R.; Telloni, D.; Terasa, C.; Teriaca, L.; Toledo-Redondo, S.; del Toro Iniesta, J. C.; Tsiropoula, G.; Tsounis, A.; Tziotziou, K.; Valentini, F.; Vaivads, A.; Vecchio, A.; Velli, M.; Verbeeck, C.; Verdini, A.; Verscharen, D.; Vilmer, N.; Vourlidas, A.; Wicks, R.; Wimmer-Schweingruber, R. F.; Wiegelmann, T.; Young, P. R.; Zhukov, A. N. Bibcode: 2020A&A...642A...3Z Altcode: 2020arXiv200910772Z Solar Orbiter is the first space mission observing the solar plasma both in situ and remotely, from a close distance, in and out of the ecliptic. The ultimate goal is to understand how the Sun produces and controls the heliosphere, filling the Solar System and driving the planetary environments. With six remote-sensing and four in-situ instrument suites, the coordination and planning of the operations are essential to address the following four top-level science questions: (1) What drives the solar wind and where does the coronal magnetic field originate?; (2) How do solar transients drive heliospheric variability?; (3) How do solar eruptions produce energetic particle radiation that fills the heliosphere?; (4) How does the solar dynamo work and drive connections between the Sun and the heliosphere? Maximising the mission's science return requires considering the characteristics of each orbit, including the relative position of the spacecraft to Earth (affecting downlink rates), trajectory events (such as gravitational assist manoeuvres), and the phase of the solar activity cycle. Furthermore, since each orbit's science telemetry will be downloaded over the course of the following orbit, science operations must be planned at mission level, rather than at the level of individual orbits. It is important to explore the way in which those science questions are translated into an actual plan of observations that fits into the mission, thus ensuring that no opportunities are missed. First, the overarching goals are broken down into specific, answerable questions along with the required observations and the so-called Science Activity Plan (SAP) is developed to achieve this. The SAP groups objectives that require similar observations into Solar Orbiter Observing Plans, resulting in a strategic, top-level view of the optimal opportunities for science observations during the mission lifetime. This allows for all four mission goals to be addressed. In this paper, we introduce Solar Orbiter's SAP through a series of examples and the strategy being followed. Title: The Polarimetric and Helioseismic Imager on Solar Orbiter Authors: Solanki, S. K.; del Toro Iniesta, J. C.; Woch, J.; Gandorfer, A.; Hirzberger, J.; Alvarez-Herrero, A.; Appourchaux, T.; Martínez Pillet, V.; Pérez-Grande, I.; Sanchis Kilders, E.; Schmidt, W.; Gómez Cama, J. M.; Michalik, H.; Deutsch, W.; Fernandez-Rico, G.; Grauf, B.; Gizon, L.; Heerlein, K.; Kolleck, M.; Lagg, A.; Meller, R.; Müller, R.; Schühle, U.; Staub, J.; Albert, K.; Alvarez Copano, M.; Beckmann, U.; Bischoff, J.; Busse, D.; Enge, R.; Frahm, S.; Germerott, D.; Guerrero, L.; Löptien, B.; Meierdierks, T.; Oberdorfer, D.; Papagiannaki, I.; Ramanath, S.; Schou, J.; Werner, S.; Yang, D.; Zerr, A.; Bergmann, M.; Bochmann, J.; Heinrichs, J.; Meyer, S.; Monecke, M.; Müller, M. -F.; Sperling, M.; Álvarez García, D.; Aparicio, B.; Balaguer Jiménez, M.; Bellot Rubio, L. R.; Cobos Carracosa, J. P.; Girela, F.; Hernández Expósito, D.; Herranz, M.; Labrousse, P.; López Jiménez, A.; Orozco Suárez, D.; Ramos, J. L.; Barandiarán, J.; Bastide, L.; Campuzano, C.; Cebollero, M.; Dávila, B.; Fernández-Medina, A.; García Parejo, P.; Garranzo-García, D.; Laguna, H.; Martín, J. A.; Navarro, R.; Núñez Peral, A.; Royo, M.; Sánchez, A.; Silva-López, M.; Vera, I.; Villanueva, J.; Fourmond, J. -J.; de Galarreta, C. Ruiz; Bouzit, M.; Hervier, V.; Le Clec'h, J. C.; Szwec, N.; Chaigneau, M.; Buttice, V.; Dominguez-Tagle, C.; Philippon, A.; Boumier, P.; Le Cocguen, R.; Baranjuk, G.; Bell, A.; Berkefeld, Th.; Baumgartner, J.; Heidecke, F.; Maue, T.; Nakai, E.; Scheiffelen, T.; Sigwarth, M.; Soltau, D.; Volkmer, R.; Blanco Rodríguez, J.; Domingo, V.; Ferreres Sabater, A.; Gasent Blesa, J. L.; Rodríguez Martínez, P.; Osorno Caudel, D.; Bosch, J.; Casas, A.; Carmona, M.; Herms, A.; Roma, D.; Alonso, G.; Gómez-Sanjuan, A.; Piqueras, J.; Torralbo, I.; Fiethe, B.; Guan, Y.; Lange, T.; Michel, H.; Bonet, J. A.; Fahmy, S.; Müller, D.; Zouganelis, I. Bibcode: 2020A&A...642A..11S Altcode: 2019arXiv190311061S
Aims: This paper describes the Polarimetric and Helioseismic Imager on the Solar Orbiter mission (SO/PHI), the first magnetograph and helioseismology instrument to observe the Sun from outside the Sun-Earth line. It is the key instrument meant to address the top-level science question: How does the solar dynamo work and drive connections between the Sun and the heliosphere? SO/PHI will also play an important role in answering the other top-level science questions of Solar Orbiter, while hosting the potential of a rich return in further science.
Methods: SO/PHI measures the Zeeman effect and the Doppler shift in the Fe I 617.3 nm spectral line. To this end, the instrument carries out narrow-band imaging spectro-polarimetry using a tunable LiNbO3 Fabry-Perot etalon, while the polarisation modulation is done with liquid crystal variable retarders. The line and the nearby continuum are sampled at six wavelength points and the data are recorded by a 2k × 2k CMOS detector. To save valuable telemetry, the raw data are reduced on board, including being inverted under the assumption of a Milne-Eddington atmosphere, although simpler reduction methods are also available on board. SO/PHI is composed of two telescopes; one, the Full Disc Telescope, covers the full solar disc at all phases of the orbit, while the other, the High Resolution Telescope, can resolve structures as small as 200 km on the Sun at closest perihelion. The high heat load generated through proximity to the Sun is greatly reduced by the multilayer-coated entrance windows to the two telescopes that allow less than 4% of the total sunlight to enter the instrument, most of it in a narrow wavelength band around the chosen spectral line.
Results: SO/PHI was designed and built by a consortium having partners in Germany, Spain, and France. The flight model was delivered to Airbus Defence and Space, Stevenage, and successfully integrated into the Solar Orbiter spacecraft. A number of innovations were introduced compared with earlier space-based spectropolarimeters, thus allowing SO/PHI to fit into the tight mass, volume, power and telemetry budgets provided by the Solar Orbiter spacecraft and to meet the (e.g. thermal) challenges posed by the mission's highly elliptical orbit. Title: The Solar Orbiter SPICE instrument. An extreme UV imaging spectrometer Authors: SPICE Consortium; Anderson, M.; Appourchaux, T.; Auchère, F.; Aznar Cuadrado, R.; Barbay, J.; Baudin, F.; Beardsley, S.; Bocchialini, K.; Borgo, B.; Bruzzi, D.; Buchlin, E.; Burton, G.; Büchel, V.; Caldwell, M.; Caminade, S.; Carlsson, M.; Curdt, W.; Davenne, J.; Davila, J.; Deforest, C. E.; Del Zanna, G.; Drummond, D.; Dubau, J.; Dumesnil, C.; Dunn, G.; Eccleston, P.; Fludra, A.; Fredvik, T.; Gabriel, A.; Giunta, A.; Gottwald, A.; Griffin, D.; Grundy, T.; Guest, S.; Gyo, M.; Haberreiter, M.; Hansteen, V.; Harrison, R.; Hassler, D. M.; Haugan, S. V. H.; Howe, C.; Janvier, M.; Klein, R.; Koller, S.; Kucera, T. A.; Kouliche, D.; Marsch, E.; Marshall, A.; Marshall, G.; Matthews, S. A.; McQuirk, C.; Meining, S.; Mercier, C.; Morris, N.; Morse, T.; Munro, G.; Parenti, S.; Pastor-Santos, C.; Peter, H.; Pfiffner, D.; Phelan, P.; Philippon, A.; Richards, A.; Rogers, K.; Sawyer, C.; Schlatter, P.; Schmutz, W.; Schühle, U.; Shaughnessy, B.; Sidher, S.; Solanki, S. K.; Speight, R.; Spescha, M.; Szwec, N.; Tamiatto, C.; Teriaca, L.; Thompson, W.; Tosh, I.; Tustain, S.; Vial, J. -C.; Walls, B.; Waltham, N.; Wimmer-Schweingruber, R.; Woodward, S.; Young, P.; de Groof, A.; Pacros, A.; Williams, D.; Müller, D. Bibcode: 2020A&A...642A..14S Altcode: 2019arXiv190901183A; 2019arXiv190901183S
Aims: The Spectral Imaging of the Coronal Environment (SPICE) instrument is a high-resolution imaging spectrometer operating at extreme ultraviolet wavelengths. In this paper, we present the concept, design, and pre-launch performance of this facility instrument on the ESA/NASA Solar Orbiter mission.
Methods: The goal of this paper is to give prospective users a better understanding of the possible types of observations, the data acquisition, and the sources that contribute to the instrument's signal.
Results: The paper discusses the science objectives, with a focus on the SPICE-specific aspects, before presenting the instrument's design, including optical, mechanical, thermal, and electronics aspects. This is followed by a characterisation and calibration of the instrument's performance. The paper concludes with descriptions of the operations concept and data processing.
Conclusions: The performance measurements of the various instrument parameters meet the requirements derived from the mission's science objectives. The SPICE instrument is ready to perform measurements that will provide vital contributions to the scientific success of the Solar Orbiter mission. Title: On attempting to automate the identification of mixed dipole modes for subgiant stars Authors: Appourchaux, T. Bibcode: 2020A&A...642A.226A Altcode: 2020arXiv200810973A Context. The existence of mixed modes in stars is a marker of stellar evolution. Their detection serves for a better determination of stellar age.
Aims: The goal of this paper is to identify the dipole modes in an automatic manner without human intervention.
Methods: I used the power spectra obtained by the Kepler mission for the application of the method. I computed asymptotic dipole mode frequencies as a function of the coupling factor and dipole period spacing, as well as other parameters. For each star, I collapsed the power in an echelle diagramme aligned onto the monopole and dipole mixed modes. The power at the null frequency was used as a figure of merit. Using a genetic algorithm, I then optimised the figure of merit by adjusting the location of the dipole frequencies in the power spectrum. Using published frequencies, I compared the asymptotic dipole mode frequencies with published frequencies. I also used published frequencies to derive the coupling factor and dipole period spacing using a non-linear least squares fit. I used Monte-Carlo simulations of the non-linear least square fit to derive error bars for each parameter.
Results: From the 44 subgiants studied, the automatic identification allows one to retrieve within 3 μHz, at least 80% of the modes for 32 stars, and within 6 μHz, at least 90% of the modes for 37 stars. The optimised and fitted gravity-mode period spacing and coupling factor are in agreement with previous measurements. Random errors for the mixed-mode parameters deduced from the Monte-Carlo simulation are about 30-50 times smaller than previously determined errors, which are in fact systematic errors.
Conclusions: The period spacing and coupling factors of mixed modes in subgiants are confirmed. The current automated procedure will need to be improved upon using a more accurate asymptotic model and/or proper statistical tests. Title: The Solar Orbiter EUI instrument: The Extreme Ultraviolet Imager Authors: Rochus, P.; Auchère, F.; Berghmans, D.; Harra, L.; Schmutz, W.; Schühle, U.; Addison, P.; Appourchaux, T.; Aznar Cuadrado, R.; Baker, D.; Barbay, J.; Bates, D.; BenMoussa, A.; Bergmann, M.; Beurthe, C.; Borgo, B.; Bonte, K.; Bouzit, M.; Bradley, L.; Büchel, V.; Buchlin, E.; Büchner, J.; Cabé, F.; Cadiergues, L.; Chaigneau, M.; Chares, B.; Choque Cortez, C.; Coker, P.; Condamin, M.; Coumar, S.; Curdt, W.; Cutler, J.; Davies, D.; Davison, G.; Defise, J. -M.; Del Zanna, G.; Delmotte, F.; Delouille, V.; Dolla, L.; Dumesnil, C.; Dürig, F.; Enge, R.; François, S.; Fourmond, J. -J.; Gillis, J. -M.; Giordanengo, B.; Gissot, S.; Green, L. M.; Guerreiro, N.; Guilbaud, A.; Gyo, M.; Haberreiter, M.; Hafiz, A.; Hailey, M.; Halain, J. -P.; Hansotte, J.; Hecquet, C.; Heerlein, K.; Hellin, M. -L.; Hemsley, S.; Hermans, A.; Hervier, V.; Hochedez, J. -F.; Houbrechts, Y.; Ihsan, K.; Jacques, L.; Jérôme, A.; Jones, J.; Kahle, M.; Kennedy, T.; Klaproth, M.; Kolleck, M.; Koller, S.; Kotsialos, E.; Kraaikamp, E.; Langer, P.; Lawrenson, A.; Le Clech', J. -C.; Lenaerts, C.; Liebecq, S.; Linder, D.; Long, D. M.; Mampaey, B.; Markiewicz-Innes, D.; Marquet, B.; Marsch, E.; Matthews, S.; Mazy, E.; Mazzoli, A.; Meining, S.; Meltchakov, E.; Mercier, R.; Meyer, S.; Monecke, M.; Monfort, F.; Morinaud, G.; Moron, F.; Mountney, L.; Müller, R.; Nicula, B.; Parenti, S.; Peter, H.; Pfiffner, D.; Philippon, A.; Phillips, I.; Plesseria, J. -Y.; Pylyser, E.; Rabecki, F.; Ravet-Krill, M. -F.; Rebellato, J.; Renotte, E.; Rodriguez, L.; Roose, S.; Rosin, J.; Rossi, L.; Roth, P.; Rouesnel, F.; Roulliay, M.; Rousseau, A.; Ruane, K.; Scanlan, J.; Schlatter, P.; Seaton, D. B.; Silliman, K.; Smit, S.; Smith, P. J.; Solanki, S. K.; Spescha, M.; Spencer, A.; Stegen, K.; Stockman, Y.; Szwec, N.; Tamiatto, C.; Tandy, J.; Teriaca, L.; Theobald, C.; Tychon, I.; van Driel-Gesztelyi, L.; Verbeeck, C.; Vial, J. -C.; Werner, S.; West, M. J.; Westwood, D.; Wiegelmann, T.; Willis, G.; Winter, B.; Zerr, A.; Zhang, X.; Zhukov, A. N. Bibcode: 2020A&A...642A...8R Altcode: Context. The Extreme Ultraviolet Imager (EUI) is part of the remote sensing instrument package of the ESA/NASA Solar Orbiter mission that will explore the inner heliosphere and observe the Sun from vantage points close to the Sun and out of the ecliptic. Solar Orbiter will advance the "connection science" between solar activity and the heliosphere.
Aims: With EUI we aim to improve our understanding of the structure and dynamics of the solar atmosphere, globally as well as at high resolution, and from high solar latitude perspectives.
Methods: The EUI consists of three telescopes, the Full Sun Imager and two High Resolution Imagers, which are optimised to image in Lyman-α and EUV (17.4 nm, 30.4 nm) to provide a coverage from chromosphere up to corona. The EUI is designed to cope with the strong constraints imposed by the Solar Orbiter mission characteristics. Limited telemetry availability is compensated by state-of-the-art image compression, onboard image processing, and event selection. The imposed power limitations and potentially harsh radiation environment necessitate the use of novel CMOS sensors. As the unobstructed field of view of the telescopes needs to protrude through the spacecraft's heat shield, the apertures have been kept as small as possible, without compromising optical performance. This led to a systematic effort to optimise the throughput of every optical element and the reduction of noise levels in the sensor.
Results: In this paper we review the design of the two elements of the EUI instrument: the Optical Bench System and the Common Electronic Box. Particular attention is also given to the onboard software, the intended operations, the ground software, and the foreseen data products.
Conclusions: The EUI will bring unique science opportunities thanks to its specific design, its viewpoint, and to the planned synergies with the other Solar Orbiter instruments. In particular, we highlight science opportunities brought by the out-of-ecliptic vantage point of the solar poles, the high-resolution imaging of the high chromosphere and corona, and the connection to the outer corona as observed by coronagraphs. Title: The Evolution of Rotation and Magnetic Activity in 94 Aqr Aa from Asteroseismology with TESS Authors: Metcalfe, Travis S.; van Saders, Jennifer L.; Basu, Sarbani; Buzasi, Derek; Chaplin, William J.; Egeland, Ricky; Garcia, Rafael A.; Gaulme, Patrick; Huber, Daniel; Reinhold, Timo; Schunker, Hannah; Stassun, Keivan G.; Appourchaux, Thierry; Ball, Warrick H.; Bedding, Timothy R.; Deheuvels, Sébastien; González-Cuesta, Lucía; Handberg, Rasmus; Jiménez, Antonio; Kjeldsen, Hans; Li, Tanda; Lund, Mikkel N.; Mathur, Savita; Mosser, Benoit; Nielsen, Martin B.; Noll, Anthony; Çelik Orhan, Zeynep; Örtel, Sibel; Santos, Ângela R. G.; Yildiz, Mutlu; Baliunas, Sallie; Soon, Willie Bibcode: 2020ApJ...900..154M Altcode: 2020arXiv200712755M Most previous efforts to calibrate how rotation and magnetic activity depend on stellar age and mass have relied on observations of clusters, where isochrones from stellar evolution models are used to determine the properties of the ensemble. Asteroseismology employs similar models to measure the properties of an individual star by matching its normal modes of oscillation, yielding the stellar age and mass with high precision. We use 27 days of photometry from the Transiting Exoplanet Survey Satellite to characterize solar-like oscillations in the G8 subgiant of the 94 Aqr triple system. The resulting stellar properties, when combined with a reanalysis of 35 yr of activity measurements from the Mount Wilson HK project, allow us to probe the evolution of rotation and magnetic activity in the system. The asteroseismic age of the subgiant agrees with a stellar isochrone fit, but the rotation period is much shorter than expected from standard models of angular momentum evolution. We conclude that weakened magnetic braking may be needed to reproduce the stellar properties, and that evolved subgiants in the hydrogen shell-burning phase can reinvigorate large-scale dynamo action and briefly sustain magnetic activity cycles before ascending the red giant branch. Title: The Solaris Solar Polar Mission Authors: Hassler, Donald M.; Newmark, Jeff; Gibson, Sarah; Harra, Louise; Appourchaux, Thierry; Auchere, Frederic; Berghmans, David; Colaninno, Robin; Fineschi, Silvano; Gizon, Laurent; Gosain, Sanjay; Hoeksema, Todd; Kintziger, Christian; Linker, John; Rochus, Pierre; Schou, Jesper; Viall, Nicholeen; West, Matt; Woods, Tom; Wuelser, Jean-Pierre Bibcode: 2020EGUGA..2217703H Altcode: The solar poles are one of the last unexplored regions of the solar system. Although Ulysses flew over the poles in the 1990s, it did not have remote sensing instruments onboard to probe the Sun's polar magnetic field or surface/sub-surface flows.We will discuss Solaris, a proposed Solar Polar MIDEX mission to revolutionize our understanding of the Sun by addressing fundamental questions that can only be answered from a polar vantage point. Solaris uses a Jupiter gravity assist to escape the ecliptic plane and fly over both poles of the Sun to >75 deg. inclination, obtaining the first high-latitude, multi-month-long, continuous remote-sensing solar observations. Solaris will address key outstanding, breakthrough problems in solar physics and fill holes in our scientific understanding that will not be addressed by current missions.With focused science and a simple, elegant mission design, Solaris will also provide enabling observations for space weather research (e.g. polar view of CMEs), and stimulate future research through new unanticipated discoveries. Title: Age dating of an early Milky Way merger via asteroseismology of the naked-eye star ν Indi Authors: Chaplin, William J.; Serenelli, Aldo M.; Miglio, Andrea; Morel, Thierry; Mackereth, J. Ted; Vincenzo, Fiorenzo; Kjeldsen, Hans; Basu, Sarbani; Ball, Warrick H.; Stokholm, Amalie; Verma, Kuldeep; Mosumgaard, Jakob Rørsted; Silva Aguirre, Victor; Mazumdar, Anwesh; Ranadive, Pritesh; Antia, H. M.; Lebreton, Yveline; Ong, Joel; Appourchaux, Thierry; Bedding, Timothy R.; Christensen-Dalsgaard, Jørgen; Creevey, Orlagh; García, Rafael A.; Handberg, Rasmus; Huber, Daniel; Kawaler, Steven D.; Lund, Mikkel N.; Metcalfe, Travis S.; Stassun, Keivan G.; Bazot, Michäel; Beck, Paul G.; Bell, Keaton J.; Bergemann, Maria; Buzasi, Derek L.; Benomar, Othman; Bossini, Diego; Bugnet, Lisa; Campante, Tiago L.; Orhan, Zeynep çelik; Corsaro, Enrico; González-Cuesta, Lucía; Davies, Guy R.; Di Mauro, Maria Pia; Egeland, Ricky; Elsworth, Yvonne P.; Gaulme, Patrick; Ghasemi, Hamed; Guo, Zhao; Hall, Oliver J.; Hasanzadeh, Amir; Hekker, Saskia; Howe, Rachel; Jenkins, Jon M.; Jiménez, Antonio; Kiefer, René; Kuszlewicz, James S.; Kallinger, Thomas; Latham, David W.; Lundkvist, Mia S.; Mathur, Savita; Montalbán, Josefina; Mosser, Benoit; Bedón, Andres Moya; Nielsen, Martin Bo; Örtel, Sibel; Rendle, Ben M.; Ricker, George R.; Rodrigues, Thaíse S.; Roxburgh, Ian W.; Safari, Hossein; Schofield, Mathew; Seager, Sara; Smalley, Barry; Stello, Dennis; Szabó, Róbert; Tayar, Jamie; Themeßl, Nathalie; Thomas, Alexandra E. L.; Vanderspek, Roland K.; van Rossem, Walter E.; Vrard, Mathieu; Weiss, Achim; White, Timothy R.; Winn, Joshua N.; Yıldız, Mutlu Bibcode: 2020NatAs...4..382C Altcode: 2020NatAs.tmp....7C; 2020arXiv200104653C Over the course of its history, the Milky Way has ingested multiple smaller satellite galaxies1. Although these accreted stellar populations can be forensically identified as kinematically distinct structures within the Galaxy, it is difficult in general to date precisely the age at which any one merger occurred. Recent results have revealed a population of stars that were accreted via the collision of a dwarf galaxy, called Gaia-Enceladus1, leading to substantial pollution of the chemical and dynamical properties of the Milky Way. Here we identify the very bright, naked-eye star ν Indi as an indicator of the age of the early in situ population of the Galaxy. We combine asteroseismic, spectroscopic, astrometric and kinematic observations to show that this metal-poor, alpha-element-rich star was an indigenous member of the halo, and we measure its age to be 11.0 ±0.7 ? (stat) ±0.8 ? (sys) billion years. The star bears hallmarks consistent with having been kinematically heated by the Gaia-Enceladus collision. Its age implies that the earliest the merger could have begun was 11.6 and 13.2 billion years ago, at 68% and 95% confidence, respectively. Computations based on hierarchical cosmological models slightly reduce the above limits. Title: Jupiter atmospheric dynamics from ground-based Doppler imaging Authors: Schmider, François-Xavier; Guillot, Tristan; Gonçalves, Ivan; Jackiewicz, Jason; Underwood, Thomas; Voelz, David; Gaulme, Patrick; Boumier, Patrick; Appourchaux, Thierry; Morales-Juberias, Raùl; Ikoma, Masahiro; Sato, Bun'ei; Izumiura, Hideyuki Bibcode: 2019EPSC...13.1613S Altcode: We present velocity maps of Jupiter obtained from the ground with a dedicated Doppler imaging spectrograph. It demonstrates the potential of this method to study the motion in the atmosphere of gaseous planets. It proves to be complementary to cloud-tracking to understand the atmospheric dynamics Title: VizieR Online Data Catalog: High-precision radial velocities for HD 221416 (Huber+, 2019) Authors: Huber, D.; Chaplin, W. J.; Chontos, A.; Kjeldsen, H.; Christensen-Dalsgaard, J.; Bedding, T. R.; Ball, W.; Brahm, R.; Espinoza, N.; Henning, T.; Jordan, A.; Sarkis, P.; Knudstrup, E.; Albrecht, S.; Grundahl, F.; Andersen, M. F.; Palle, P. L.; Crossfield, I.; Fulton, B.; Howard, A. W.; Isaacson, H. T.; Weiss, L. M.; Handberg, R.; Lund, M. N.; Serenelli, A. M.; Rorsted Mosumgaard, J.; Stokholm, A.; Bieryla, A.; Buchhave, L. A.; Latham, D. W.; Quinn, S. N.; Gaidos, E.; Hirano, T.; Ricker, G. R.; Vanderspek, R. K.; Seager, S.; Jenkins, J. M.; Winn, J. N.; Antia, H. M.; Appourchaux, T.; Basu, S.; Bell, K. J.; Benomar, O.; Bonanno, A.; Buzasi, D. L.; Campante, T. L.; Celik Orhan, Z.; Corsaro, E.; Cunha, M. S.; Davies, G. R.; Deheuvels, S.; Grunblatt, S. K.; Hasanzadeh, A.; di Mauro, M. P.; Garcia, R. A.; Gaulme, P.; Girardi, L.; Guzik, J. A.; Hon, M.; Jiang, C.; Kallinger, T.; Kawaler, S. D.; Kuszlewicz, J. S.; Lebreton, Y.; Li, T.; Lucas, M.; Lundkvist, M. S.; Mann, A. W.; Mathis, S.; Mathur, S.; Mazumdar, A.; Metcalfe, T. S.; Miglio, A.; Monteiro, M. J. P. F. G.; Mosser, B.; Noll, A.; Nsamba, B.; Ong, J. M. J.; Ortel, S.; Pereira, F.; Ranadive, P.; Regulo, C.; Rodrigues, T. S.; Roxburgh, I. W.; Aguirre, V. S.; Smalley, B.; Schofield, M.; Sousa, S. G.; Stassun, K. G.; Stello, D.; Tayar, J.; White, T. R.; Verma, K.; Vrard, M.; Yildiz, M.; Baker, D.; Bazot, M.; Beichmann, C.; Bergmann, C.; Bugnet, L.; Cale, B.; Carlino, R.; Cartwright, S. M.; Christiansen, J. L.; Ciardi, D. R.; Creevey, O.; Dittmann, J. A.; Do Nascimento, J. -D., Jr.; van Eylen, V.; Furesz, G.; Gagne, J.; Gao, P.; Gazeas, K.; Giddens, F.; Hall, O. J.; Hekker, S.; Ireland, M. J.; Latouf, N.; Lebrun, D.; Levine, A. M.; Matzko, W.; Natinsky, E.; Page, E.; Plavchan, P.; Mansouri-Samani, M.; McCauliff, S.; Mullally, S. E.; Orenstein, B.; Soto, A. G.; Paegert, M.; van Saders, J. L.; Schnaible, C.; Soderblom, D. R.; Szabo, R.; Tanner, A.; Tinney, C. G.; Teske, J.; Thomas, A.; Trampedach, R.; Wright, D.; Yuan, T. T.; Zohrabi, F. Bibcode: 2019yCat..51570245H Altcode: We obtained high-resolution spectra of HD 221416 using several facilities within the TESS Follow-up Observation Program (TFOP), including HIRES (Vogt et al. 1994SPIE.2198..362V) on the 10 m telescope at Keck Observatory (Maunakea, Hawai'i); the Hertzsprung SONG Telescope at Teide Observatory (Tenerife; Grundahl et al. 2017ApJ...836..142G); HARPS (Mayor et al. 2003Msngr.114...20M), FEROS (Kaufer et al. 1999Msngr..95....8K), Coralie (Queloz et al. 2001Msngr.105....1Q), and FIDEOS (Vanzi et al. 2018MNRAS.477.5041V) on the MPG/ESO 3.6 m, 2.2 m, 1.2 m, and 1 m telescopes at La Silla Observatory (Chile); Veloce (Gilbert et al. 2018SPIE10702E..0YG) on the 3.9 m Anglo-Australian Telescope at Siding Spring Observatory (Australia); TRES (Furesz 2008, PhD thesis Univ. Szeged) on the 1.5 m Tillinghast reflector at the F. L. Whipple Observatory (Mt. Hopkins, Arizona); and iSHELL (Rayner et al. 2012SPIE.8446E..2CR) on the NASA IRTF Telescope (Maunakea, Hawai'i). All spectra used in this paper were obtained between 2018 November 11 and December 30 and have a minimum spectral resolution of R~44000.

(1 data file). Title: Damping rates and frequency corrections of Kepler LEGACY stars Authors: Houdek, G.; Lund, M. N.; Trampedach, R.; Christensen-Dalsgaard, J.; Handberg, R.; Appourchaux, T. Bibcode: 2019MNRAS.487..595H Altcode: 2019MNRAS.tmp.1157H; 2019arXiv190413170H Linear damping rates and modal frequency corrections of radial oscillation modes in selected LEGACY main-sequence stars are estimated by means of a non-adiabatic stability analysis. The selected stellar sample covers stars observed by Kepler with a large range of surface temperatures and surface gravities. A non-local, time-dependent convection model is perturbed to assess stability against pulsation modes. The mixing-length parameter is calibrated to the surface-convection-zone depth of a stellar model obtained from fitting adiabatic frequencies to the LEGACY observations, and two of the non-local convection parameters are calibrated to the corresponding LEGACY linewidth measurements. The remaining non-local convection parameters in the 1D calculations are calibrated so as to reproduce profiles of turbulent pressure and of the anisotropy of the turbulent velocity field of corresponding 3D hydrodynamical simulations. The atmospheric structure in the 1D stability analysis adopts a temperature-optical-depth relation derived from 3D hydrodynamical simulations. Despite the small number of parameters to adjust, we find good agreement with detailed shapes of both turbulent pressure profiles and anisotropy profiles with depth, and with damping rates as a function of frequency. Furthermore, we find the absolute modal frequency corrections, relative to a standard adiabatic pulsation calculation, to increase with surface temperature and surface gravity. Title: A Hot Saturn Orbiting an Oscillating Late Subgiant Discovered by TESS Authors: Huber, Daniel; Chaplin, William J.; Chontos, Ashley; Kjeldsen, Hans; Christensen-Dalsgaard, Jørgen; Bedding, Timothy R.; Ball, Warrick; Brahm, Rafael; Espinoza, Nestor; Henning, Thomas; Jordán, Andrés; Sarkis, Paula; Knudstrup, Emil; Albrecht, Simon; Grundahl, Frank; Fredslund Andersen, Mads; Pallé, Pere L.; Crossfield, Ian; Fulton, Benjamin; Howard, Andrew W.; Isaacson, Howard T.; Weiss, Lauren M.; Handberg, Rasmus; Lund, Mikkel N.; Serenelli, Aldo M.; Rørsted Mosumgaard, Jakob; Stokholm, Amalie; Bieryla, Allyson; Buchhave, Lars A.; Latham, David W.; Quinn, Samuel N.; Gaidos, Eric; Hirano, Teruyuki; Ricker, George R.; Vanderspek, Roland K.; Seager, Sara; Jenkins, Jon M.; Winn, Joshua N.; Antia, H. M.; Appourchaux, Thierry; Basu, Sarbani; Bell, Keaton J.; Benomar, Othman; Bonanno, Alfio; Buzasi, Derek L.; Campante, Tiago L.; Çelik Orhan, Z.; Corsaro, Enrico; Cunha, Margarida S.; Davies, Guy R.; Deheuvels, Sebastien; Grunblatt, Samuel K.; Hasanzadeh, Amir; Di Mauro, Maria Pia; García, Rafael A.; Gaulme, Patrick; Girardi, Léo; Guzik, Joyce A.; Hon, Marc; Jiang, Chen; Kallinger, Thomas; Kawaler, Steven D.; Kuszlewicz, James S.; Lebreton, Yveline; Li, Tanda; Lucas, Miles; Lundkvist, Mia S.; Mann, Andrew W.; Mathis, Stéphane; Mathur, Savita; Mazumdar, Anwesh; Metcalfe, Travis S.; Miglio, Andrea; Monteiro, Mário J. P. F. G.; Mosser, Benoit; Noll, Anthony; Nsamba, Benard; Ong, Jia Mian Joel; Örtel, S.; Pereira, Filipe; Ranadive, Pritesh; Régulo, Clara; Rodrigues, Thaíse S.; Roxburgh, Ian W.; Silva Aguirre, Victor; Smalley, Barry; Schofield, Mathew; Sousa, Sérgio G.; Stassun, Keivan G.; Stello, Dennis; Tayar, Jamie; White, Timothy R.; Verma, Kuldeep; Vrard, Mathieu; Yıldız, M.; Baker, David; Bazot, Michaël; Beichmann, Charles; Bergmann, Christoph; Bugnet, Lisa; Cale, Bryson; Carlino, Roberto; Cartwright, Scott M.; Christiansen, Jessie L.; Ciardi, David R.; Creevey, Orlagh; Dittmann, Jason A.; Do Nascimento, Jose-Dias, Jr.; Van Eylen, Vincent; Fürész, Gabor; Gagné, Jonathan; Gao, Peter; Gazeas, Kosmas; Giddens, Frank; Hall, Oliver J.; Hekker, Saskia; Ireland, Michael J.; Latouf, Natasha; LeBrun, Danny; Levine, Alan M.; Matzko, William; Natinsky, Eva; Page, Emma; Plavchan, Peter; Mansouri-Samani, Masoud; McCauliff, Sean; Mullally, Susan E.; Orenstein, Brendan; Garcia Soto, Aylin; Paegert, Martin; van Saders, Jennifer L.; Schnaible, Chloe; Soderblom, David R.; Szabó, Róbert; Tanner, Angelle; Tinney, C. G.; Teske, Johanna; Thomas, Alexandra; Trampedach, Regner; Wright, Duncan; Yuan, Thomas T.; Zohrabi, Farzaneh Bibcode: 2019AJ....157..245H Altcode: 2019arXiv190101643H We present the discovery of HD 221416 b, the first transiting planet identified by the Transiting Exoplanet Survey Satellite (TESS) for which asteroseismology of the host star is possible. HD 221416 b (HIP 116158, TOI-197) is a bright (V = 8.2 mag), spectroscopically classified subgiant that oscillates with an average frequency of about 430 μHz and displays a clear signature of mixed modes. The oscillation amplitude confirms that the redder TESS bandpass compared to Kepler has a small effect on the oscillations, supporting the expected yield of thousands of solar-like oscillators with TESS 2 minute cadence observations. Asteroseismic modeling yields a robust determination of the host star radius (R ⋆ = 2.943 ± 0.064 R ⊙), mass (M ⋆ = 1.212 ± 0.074 M ⊙), and age (4.9 ± 1.1 Gyr), and demonstrates that it has just started ascending the red-giant branch. Combining asteroseismology with transit modeling and radial-velocity observations, we show that the planet is a “hot Saturn” (R p = 9.17 ± 0.33 R ⊕) with an orbital period of ∼14.3 days, irradiance of F = 343 ± 24 F ⊕, and moderate mass (M p = 60.5 ± 5.7 M ⊕) and density (ρ p = 0.431 ± 0.062 g cm-3). The properties of HD 221416 b show that the host-star metallicity-planet mass correlation found in sub-Saturns (4-8 R ⊕) does not extend to larger radii, indicating that planets in the transition between sub-Saturns and Jupiters follow a relatively narrow range of densities. With a density measured to ∼15%, HD 221416 b is one of the best characterized Saturn-size planets to date, augmenting the small number of known transiting planets around evolved stars and demonstrating the power of TESS to characterize exoplanets and their host stars using asteroseismology. Title: Searching for g modes. II. Unconfirmed g-mode detection in the power spectrum of the time series of round-trip travel time Authors: Appourchaux, T.; Corbard, T. Bibcode: 2019A&A...624A.106A Altcode: 2019arXiv190303791A Context. The recent claims of g-mode detection have restarted the search for these potentially extremely important modes. The claimed detection of g modes was obtained from the analysis of the power spectrum of the time series of round-trip travel time of p modes.
Aims: The goal of this paper is to reproduce these results on which the claims are based for confirming or invalidating the detection of g modes with the method used to make the claims.
Methods: We computed the time series of round-trip travel time using the procedure given in Fossat et al. (2017, A&A, 604, A40), and used different variations of the times series for comparison. We used the recently calibrated GOLF data (published in Paper I) with different sampling, different photomultipliers, different length of data for reproducing the analysis. We also correlated the power spectrum with an asymptotic model of g-mode frequencies in a similar manner to Fossat and Schmider (2018, A&A, 612, L1). We devised a scheme for optimising the correlation both for pure noise and for the GOLF data.
Results: We confirm the analysis performed in Fossat et al. (2017) but draw different conclusions. Their claims of detection of g modes cannot be confirmed when changing parameters such as sampling interval, length of time series, or photomultipliers. Other instrument such as GONG and BiSON do not confirm their detection. We also confirm the analysis performed in Fossat and Schmider (2018), but again draw different conclusions. For GOLF, the correlation of the power spectrum with the asymptotic model of g-mode frequencies for l = 1 and l = 2 show a high correlation at lag=0 and at lag corresponding to the rotational splitting νl, but the same occurs for pure noise due to the large number of peaks present in the model. In addition, other very different parameters defining the asymptotic model also provide a high correlation at these lags. We conclude that the detection performed in Fossat and Schmider (2018) is an artefact of the methodology. Title: VizieR Online Data Catalog: Asymmetry of oscillations in 43 Kepler stars (Benomar+, 2018) Authors: Benomar, O.; Goupil, M.; Belkacem, K.; Appourchaux, T.; Nielsen, M. B.; Bazot, M.; Gizon, L.; Hanasoge, S.; Sreenivasan, K. R.; Marchand, B. Bibcode: 2019yCat..18570119B Altcode: In this work, the considered ensemble of stars is a subset of the Kepler LEGACY sample (Lund+ 2017, J/ApJ/835/172). We selected 43 stars for analysis out of 66 of the LEGACY sample. The current analysis uses the unweighted power spectra provided by the Kepler Asteroseismic Science Operations Center (KASOC) pipeline (http://kasoc.phys.au.dk/).

(2 data files). Title: The Asteroseismic Target List for Solar-like Oscillators Observed in 2 minute Cadence with the Transiting Exoplanet Survey Satellite Authors: Schofield, Mathew; Chaplin, William J.; Huber, Daniel; Campante, Tiago L.; Davies, Guy R.; Miglio, Andrea; Ball, Warrick H.; Appourchaux, Thierry; Basu, Sarbani; Bedding, Timothy R.; Christensen-Dalsgaard, Jørgen; Creevey, Orlagh; García, Rafael A.; Handberg, Rasmus; Kawaler, Steven D.; Kjeldsen, Hans; Latham, David W.; Lund, Mikkel N.; Metcalfe, Travis S.; Ricker, George R.; Serenelli, Aldo; Silva Aguirre, Victor; Stello, Dennis; Vanderspek, Roland Bibcode: 2019ApJS..241...12S Altcode: 2019arXiv190110148S We present the target list of solar-type stars to be observed in short-cadence (2 minute) for asteroseismology by the NASA Transiting Exoplanet Survey Satellite (TESS) during its 2 year nominal survey mission. The solar-like Asteroseismic Target List (ATL) is comprised of bright, cool main-sequence and subgiant stars and forms part of the larger target list of the TESS Asteroseismic Science Consortium. The ATL uses the Gaia Data Release 2 and the Extended Hipparcos Compilation (XHIP) to derive fundamental stellar properties, to calculate detection probabilities, and to produce a rank-ordered target list. We provide a detailed description of how the ATL was produced and calculate expected yields for solar-like oscillators based on the nominal photometric performance by TESS. We also provide a publicly available source code that can be used to reproduce the ATL, thereby enabling comparisons of asteroseismic results from TESS with predictions from synthetic stellar populations. Title: First measurements of Jupiter's zonal winds with visible imaging spectroscopy Authors: Gonçalves, Ivan; Schmider, F. X.; Gaulme, Patrick; Morales-Juberías, Raúl; Guillot, Tristan; Rivet, Jean-Pierre; Appourchaux, Thierry; Boumier, Patrick; Jackiewicz, Jason; Sato, Bun'ei; Ida, Shigeru; Ikoma, Masahiro; Mékarnia, Djamel; Underwood, Thomas A.; Voelz, David Bibcode: 2019Icar..319..795G Altcode: We present the first measurements of Jupiter's wind profile ever obtained with Doppler velocity measurements in the visible. Hitherto, knowledge about atmospheric dynamics has been obtained with cloud-tracking techniques, which consist of tracking visible features from images taken at different dates. However, cloud tracking indicates the motion of large cloud structures, which is an indication of the speed of iso-pressure regions, rather than the speed of the actual atmospheric particles. Doppler imaging is as challenging - motions are usually less than 100 m s-1 - as appealing because it measures the speed of cloud particles instead of large cloud structures. Significant difference could appear in the case of atmospheric waves interfering with cloud structures. Here we present the first scientific results of a Doppler imaging spectrometer that is dedicated to giant-planet seismology and atmospheric dynamics by providing instantaneous line-of-sight-velocity maps of the planets of the solar system. The instrument has been developed in the framework of the projects JOVIAL (Jovian Oscillations through Velocity Images At several Longitudes) and JIVE in NM (Jovian Interiors from Velocimetry Experiment in New Mexico). It is a Fourier transform spectrometer with a fixed optical path difference working in the mid-visible domain, which monitors the position of solar Fraunhofer lines that are reflected in the planets' upper atmospheres. After describing the instrument principle and the different steps of data reduction, we report measurement of the average zonal wind speed of Jupiter, as a function of latitude, from datasets obtained in 2015 and 2016 with two different telescopes, when the planet was close to its opposition. Our results are consistent between the two years. We compare the results with wind profiles obtained by cloud tracking on HST (Hubble Space Telescope) images taken at the same epoch, and identify a significant discrepancy in the North Equatorial Belt and northern part of the Equatorial Zone. Title: Searching for g modes. I. A new calibration of the GOLF instrument Authors: Appourchaux, T.; Boumier, P.; Leibacher, J. W.; Corbard, T. Bibcode: 2018A&A...617A.108A Altcode: 2018arXiv180700998A Context. The recent claims of g-mode detection have restarted the search for these potentially extremely important modes. These claims can be reassessed in view of the different data sets available from the SoHO instruments and ground-based instruments.
Aims: We produce a new calibration of the GOLF data with a more consistent p-mode amplitude and a more consistent time shift correction compared to the time series used in the past.
Methods: The calibration of 22 yr of GOLF data is done with a simpler approach that uses only the predictive radial velocity of the SoHO spacecraft as a reference. Using p modes, we measure and correct the time shift between ground- and space-based instruments and the GOLF instrument.
Results: The p-mode velocity calibration is now consistent to within a few percent with other instruments. The remaining time shifts are within ±5 s for 99.8% of the time series.

The new calibrated series (FITS) are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/617/A108 Title: First measurements of the Jovian zonal winds profile through visible Doppler spectroscopy Authors: Schmider, François-Xavier; Goncalves, Ivan; Gaulme, Patrick; Morales-Jubieras, Raul; Guillot, Tristan; Appourchaux, Thierry; Boumier, Patrick; Jackiewicz, Jason; Underwood, Thomas; Voelz, David; Sato, Bun'ei; Ida, Shigeru; Ikoma, Masahiro; Rivet, Jean-Pierre Bibcode: 2018EPSC...12..433S Altcode: We present the first measurements of Jupiter's wind profile ever obtained with radial-velocity measurements. We report measurement of the average zonal wind speed of Jupiter, as function of latitude, from datasets obtained in 2016 and 2017 during the planet's opposition. We compare our results with simultaneous wind profiles obtained by cloud tracking from Hubble-space-telescope images, and point out a significant discrepancy at the latitude of the hot spots in the northern equatorial band, around 5° N. Title: Asteroseismic and orbital analysis of the triple star system HD 188753 observed by Kepler Authors: Marcadon, F.; Appourchaux, T.; Marques, J. P. Bibcode: 2018A&A...617A...2M Altcode: 2018arXiv180409296M Context. The NASA Kepler space telescope has detected solar-like oscillations in several hundreds of single stars, thereby providing a way to determine precise stellar parameters using asteroseismology.
Aims: In this work, we aim to derive the fundamental parameters of a close triple star system, HD 188753, for which asteroseismic and astrometric observations allow independent measurements of stellar masses.
Methods: We used six months of Kepler photometry available for HD 188753 to detect the oscillation envelopes of the two brightest stars. For each star, we extracted the individual mode frequencies by fitting the power spectrum using a maximum likelihood estimation approach. We then derived initial guesses of the stellar masses and ages based on two seismic parameters and on a characteristic frequency ratio, and modelled the two components independently with the stellar evolution code CESTAM. In addition, we derived the masses of the three stars by applying a Bayesian analysis to the position and radial-velocity measurements of the system.
Results: Based on stellar modelling, the mean common age of the system is 10.8 ± 0.2 Gyr and the masses of the two seismic components are MA = 0.99 ± 0.01 M⊙ and MBa = 0.86 ± 0.01 M⊙. From the mass ratio of the close pair, MBb/MBa = 0.767 ± 0.006, the mass of the faintest star is MBb = 0.66 ± 0.01 M⊙ and the total seismic mass of the system is then Msyst = 2.51 ± 0.02 M⊙. This value agrees perfectly with the total mass derived from our orbital analysis, Msyst = 2.51-0.18+0.20 M⊙, and leads to the best current estimate of the parallax for the system, π = 21.9 ± 0.2 mas. In addition, the minimal relative inclination between the inner and outer orbits is 10.9° ± 1.5°, implying that the system does not have a coplanar configuration. Title: The High Resolution Telescope (HRT) of the Polarimetric and Helioseismic Imager (PHI) onboard Solar Orbiter Authors: Gandorfer, A.; Grauf, B.; Staub, J.; Bischoff, J.; Woch, J.; Hirzberger, J.; Solanki, S. K.; Álvarez-Herrero, A.; García Parejo, P.; Schmidt, W.; Volkmer, R.; Appourchaux, T.; del Toro Iniesta, J. C. Bibcode: 2018SPIE10698E..4NG Altcode: Solar Orbiter is a joint mission of ESA and NASA scheduled for launch in 2020. Solar Orbiter is a complete and unique heliophysics mission, combining remote sensing and in-situ analysis; its special elliptical orbit allows viewing the Sun from a distance of only 0.28 AU, and - leaving the ecliptic plane - to observe the solar poles from a hitherto unexplored vantage point. One of the key instruments for Solar Orbiter's science is the "Polarimetric and Helioseismic Imager" (PHI), which will provide maps of the solar surface magnetic fields and the gas flows on the visible solar surface. Two telescopes, a full disc imager, and a high resolution channel feed a common Fabry-Perot based tunable filter and thus allow sampling a single Fraunhofer line at 617.3 nm with high spectral resolution; a polarization modulation system makes the system sensitive to the full state of polarization. From the analysis of the Doppler shift and the magnetically induced Zeeman polarization in this line, the magnetic field and the line-of-sight gas motions can be detected for each point in the image. In this paper we describe the opto-mechanical system design of the high resolution telescope. It is based on a decentred Ritchey-Chrétien two-mirror telescope. The telescope includes a Barlow type magnifier lens group, which is used as in-orbit focus compensator, and a beam splitter, which sends a small fraction of the collected light onto a fast camera, which provides the error signals for the actively controlled secondary mirror compensating for spacecraft jitter and other disturbances. The elliptical orbit of the spacecraft poses high demands on the thermo-mechanical stability. The varying size of the solar disk image requires a special false-light suppression architecture, which is briefly described. In combination with a heat-rejecting entrance window, the optical energy impinging on the polarimetric and spectral analysis system is efficiently reduced. We show how the design can preserve the diffraction-limited imaging performance over the design temperature range of -20°C to +60°C. The decentred hyperbolical mirrors require special measures for the inter-alignment and their alignment with respect to the mechanical structure. A system of alignment flats and mechanical references is used for this purpose. We will describe the steps of the alignment procedure, and the dedicated optical ground support equipment, which are needed to reach the diffraction limited performance of the telescope. We will also report on the verification of the telescope performance, both - in ambient condition - and in vacuum at different temperatures. Title: VizieR Online Data Catalog: Sun velocities from GOLF instrument (Appourchaux+, 2018) Authors: Appourchaux, T.; Boumier, P.; Leibacher, J. W.; Corbard, T. Bibcode: 2018yCat..36170108A Altcode: Three time series as FITS file comprising 34797600 data points of GOLF velocity in m/s sampled at 20 sec (no time provided). The time series starts on April 11, 1996 0:00 UT and ends on April 10, 2018 23:59:40 UT. The time series are provided for the photomultipliers PM1 and PM2, and their arithmetic average.

(2 data files). Title: Exploring the poles of the Sun: POLAR Investigation of the Sun (POLARIS+) Authors: Appourchaux, Thierry Bibcode: 2018tess.conf11001A Altcode: The POLAR Investigation of the Sun (POLARIS+) idea is one that has been developed over a number of years, and is supported by scientists in Europe, US, India and Japan so far. It uses a combination of a gravity assist and solar sail propulsion to place a spacecraft in a 0.48 AU circular orbit around the Sun with an inclination of 75º with respect to solar equator. In this orbit, at least 59% of the time will be spent at latitudes higher than the maximum latitude reached by Solar Orbiter (»32º). This first extended view of the high-latitude regions of the Sun will enable crucial observations not possible from the ecliptic viewpoint or from Solar Orbiter. While Solar Orbiter will give the first glimpse of the high latitude magnetic field and flows to probe the solar dynamo, it does not have sufficient viewing of the polar regions to achieve POLARIS+ primary objective: determining the relation between the magnetism and dynamics of the Sun's polar regions and the solar cycle.

The scientific payload needed to achieve these objectives consists of a set of remote-sensing instruments. All instruments have a very high TRL being derived from past and current missions such as Solar Orbiter. The payload will consist of remote sensing instruments: <li>Dopplergraph and magnetograph imager</li> <li>White-light coronagraph (classical and heliospheric)</li> <li>EUV imager</li> <li>UV spectrograph</li> <li>Total Solar Irradiance monitor</li>

All imaging instruments will have a typical resolution of 2 to 4 arcseconds. In-situ instruments could also be considered as an interesting addition for following up on the success of the ESA's Ulysses mission.

Extended observations from high latitudes will revolutionize our understanding of the internal structure and dynamics of the Sun and its atmosphere. The rapid, 4-month polar orbit (allowed by the use of solar sails) combined with a suite of remote-sensing instrumentation further enables unprecedented studies of the physical connection between the Sun and the corona. Moreover, POLARIS+ serves as a pathfinder for a permanent solar polar sentinel for space-weather prediction in support of NASA's Vision for Space Exploration, of ESA's Space Situational Awareness and a broad range of other programs affected by space weather. Title: Asymmetry of Line Profiles of Stellar Oscillations Measured by Kepler for Ensembles of Solar-like Oscillators: Impact on Mode Frequencies and Dependence on Effective Temperature Authors: Benomar, O.; Goupil, Mjo.; Belkacem, K.; Appourchaux, T.; Nielsen, M. B.; Bazot, M.; Gizon, L.; Hanasoge, S.; Sreenivasan, K. R.; Marchand, B. Bibcode: 2018ApJ...857..119B Altcode: 2018arXiv180406117B Oscillation properties are usually measured by fitting symmetric Lorentzian profiles to the power spectra of Sun-like stars. However, the line profiles of solar oscillations have been observed to be asymmetrical for the Sun. The physical origin of this line asymmetry is not fully understood; though, it should depend on the depth dependence of the source of wave excitation (convective turbulence) and details of the observable (velocity or intensity). For oscillations of the Sun, it has been shown that neglecting the asymmetry leads to systematic errors in the frequency determination. This could subsequently affect the results of seismic inferences of the solar internal structure. Using light curves from the Kepler spacecraft, we have measured mode asymmetries in 43 stars. We confirm that neglecting the asymmetry leads to systematic errors that can exceed the 1σ confidence intervals for seismic observations longer than one year. Therefore, the application of an asymmetric Lorentzian profile should be favored to improve the accuracy of the internal stellar structure and stellar fundamental parameters. We also show that the asymmetry changes sign between cool Sun-like stars and hotter stars. This provides the best constraints to date on the location of the excitation sources across the Hertzsprung-Russel diagram. Title: Helioseismology: Observations and Space Missions Authors: Palle, P. L.; Appourchaux, T.; Christensen-Dalsgaard, J.; Garcia, R. A. Bibcode: 2018arXiv180200674P Altcode: The great success of Helioseismology resides in the remarkable progress achieved in the understanding of the structure and dynamics of the solar interior. This success mainly relies on the ability to conceive, implement, and operate specific instrumentation with enough sensitivity to detect and measure small fluctuations (in velocity and/or intensity) on the solar surface that are well below one meter per second or a few parts per million. Furthermore the limitation of the ground observations imposing the day-night cycle (thus a periodic discontinuity in the observations) was overcome with the deployment of ground-based networks --properly placed at different longitudes all over the Earth-- allowing longer and continuous observations of the Sun and consequently increasing their duty cycles. In this chapter, we start by a short historical overview of helioseismology. Then we describe the different techniques used to do helioseismic analyses along with a description of the main instrumental concepts. We in particular focus on the instruments that have been operating long enough to study the solar magnetic activity. Finally, we give a highlight of the main results obtained with such high-duty cycle observations (>80%) lasting over the last few decades. Title: VizieR Online Data Catalog: 61 main-sequence and subgiant oscillations (Appourchaux+, 2012) Authors: Appourchaux, T.; Chaplin, W. J.; Garcia, R. A.; Gruberbauer, M.; Verner, G. A.; Antia, H. M.; Benomar, O.; Campante, T. L.; Davies, G. R.; Deheuvels, S.; Handberg, R.; Hekker, S.; Howe, R.; Regulo, C.; Salabert, D.; Bedding, T. R.; White, T. R.; Ballot, J.; Mathur, S.; Silva Aguirre, V.; Elsworth, Y. P.; Basu, S.; Gilliland, R. L.; Christensen-Dalsgaard, J.; Kjeldsen, H.; Uddin, K.; Stumpe, M. C.; Barclay, T. Bibcode: 2017yCat..35430054A Altcode: Kepler observations are obtained in two different operating modes: long cadence (LC) and short cadence (SC) (Gilliland et al., 2010ApJ...713L.160G; Jenkins et al., 2010ApJ...713L..87J). This work is based on SC data. For the brightest stars (down to Kepler magnitude, Kp~=12), SC observations can be obtained for a limited number of stars (up to 512 at any given time) with a faster sampling cadence of 58.84876s (Nyquist frequency of ~8.5mHz), which permits a more precise transit timing and the performance of asteroseismology. Kepler observations are divided into three-month-long quarters (Q). A subset of 61 solar-type stars observed during quarters Q5-Q7 (March 22, 2010 to December 22, 2010) were chosen because they have oscillation modes with high signal-to-noise ratios. This length of data gives a frequency resolution of about 0.04uHz.

(2 data files). Title: Conception and test of Echoes, a spectro-imager dedicated to the seismology of Jupiter Authors: Soulat, L.; Schmider, F. -X.; Robbe-Dubois, S.; Appourchaux, T.; Gaulme, P.; Bresson, Y.; Gay, J.; Daban, J. -B.; Gouvret, C. Bibcode: 2017SPIE10564E..1VS Altcode: Echoes is a project of a spaceborne Doppler Spectro-Imager (DSI) which has been proposed as payload to the JUICE mission project selected in the Cosmic Vision program of the European Space Agency (ESA). It is a Fourier transform spectrometer which measures phase shifts in the interference patterns induced by Doppler shifts of spectral lines reflected at the surface of the planet. Dedicated to the seismology of Jupiter, the instrument is designed to analyze the periodic movements induced by internal acoustic modes of the planet. It will allow the knowledge of the internal structure of Jupiter, in particular of the central region, which is essential for the comprehension of the scenario of the giant planets' formation. The optical design is based on a modified Mach-Zehnder interferometer operating in the visible domain and takes carefully into account the sensitivity of the optical path difference to the temperature. The instrument produces simultaneously four images in quadrature which allows the measurement of the phase without being contaminated by the continuum component of the incident light. We expect a noise level less than 1 cm2s-2µHz-1 in the frequency range [0.5 -10] mHz. In this paper, we present the prototype implemented at the Observatoire de la Côte d'Azur (OCA) in collaboration with Institut d'Astrophysique Spatiale (IAS) to study the real performances in laboratory and to demonstrate the capability to reach the required Technology Readiness Level 5. Title: VizieR Online Data Catalog: Asterosismology for solar analogues 16 Cyg A/B (Davies+, 2015) Authors: Davies, G. R.; Chaplin, W. J.; Farr, W. M.; Garcia, R. A.; Lund, M. N.; Mathis, S.; Metcalfe, T. S.; Appourchaux, T.; Basu, S.; Benomar, O.; Campante, T. L.; Ceillier, T.; Elsworth, Y.; Handberg, R.; Salabert, D.; Stello, D. Bibcode: 2017yCat..74462959D Altcode: Both 16 Cyg A and B are brighter (V~6) than the saturation limit for which Kepler observations were designed. However, it was possible to capture the full stellar flux by using custom photometric aperture masks. Thus, 928 d of short-cadence observations (Gilliland et al. 2010ApJ...713L.160G) - from Quarter 7 to 16 - were generated using simple aperture photometry (Jenkins et al. 2010ApJ...713L..87J) and then corrected for instrumental perturbations following the methods described by Garcia et al. (2011MNRAS.414L...6G). The final light curves used for asteroseismic analyses were high-pass filtered using a triangular smooth of 4 d width and have a duty cycle of 90.5 per cent. The power density spectra were computed using a Lomb-Scargle algorithm.

(2 data files). Title: Definition of a metrology servo-system for a solar imaging fourier transform spectrometer working in the far UV (IFTSUV) Authors: Ruiz de Galarreta Fanju, C.; Philippon, A.; Bouzit, M.; Appourchaux, T.; Vial, J. -C.; Maillard, J. -P.; Lemaire, P. Bibcode: 2017SPIE10564E..3ER Altcode: The understanding of the solar outer atmosphere requires a simultaneous combination of imaging and spectral observations concerning the far UV lines that arise from the high chromospheres up to the corona. These observations must be performed with enough spectral, spatial and temporal resolution to reveal the small atmospheric structures and to resolve the solar dynamics. An Imaging Fourier Transform Spectrometer working in the far-UV (IFTSUV, Figure 1) is an attractive instrumental solution to fulfill these requirements. However, due to the short wavelength, to preserve IFTSUV spectral precision and Signal to Noise Ratio (SNR) requires a high optical surface quality and a very accurate (linear and angular) metrology to maintain the optical path difference (OPD) during the entire scanning process by: optical path difference sampling trigger; and dynamic alignment for tip/tilt compensation (Figure 2). Title: PLATO as it is : A legacy mission for Galactic archaeology Authors: Miglio, A.; Chiappini, C.; Mosser, B.; Davies, G. R.; Freeman, K.; Girardi, L.; Jofré, P.; Kawata, D.; Rendle, B. M.; Valentini, M.; Casagrande, L.; Chaplin, W. J.; Gilmore, G.; Hawkins, K.; Holl, B.; Appourchaux, T.; Belkacem, K.; Bossini, D.; Brogaard, K.; Goupil, M. -J.; Montalbán, J.; Noels, A.; Anders, F.; Rodrigues, T.; Piotto, G.; Pollacco, D.; Rauer, H.; Prieto, C. Allende; Avelino, P. P.; Babusiaux, C.; Barban, C.; Barbuy, B.; Basu, S.; Baudin, F.; Benomar, O.; Bienaymé, O.; Binney, J.; Bland-Hawthorn, J.; Bressan, A.; Cacciari, C.; Campante, T. L.; Cassisi, S.; Christensen-Dalsgaard, J.; Combes, F.; Creevey, O.; Cunha, M. S.; Jong, R. S.; Laverny, P.; Degl'Innocenti, S.; Deheuvels, S.; Depagne, É.; Ridder, J.; Matteo, P. Di; Mauro, M. P. Di; Dupret, M. -A.; Eggenberger, P.; Elsworth, Y.; Famaey, B.; Feltzing, S.; García, R. A.; Gerhard, O.; Gibson, B. K.; Gizon, L.; Haywood, M.; Handberg, R.; Heiter, U.; Hekker, S.; Huber, D.; Ibata, R.; Katz, D.; Kawaler, S. D.; Kjeldsen, H.; Kurtz, D. W.; Lagarde, N.; Lebreton, Y.; Lund, M. N.; Majewski, S. R.; Marigo, P.; Martig, M.; Mathur, S.; Minchev, I.; Morel, T.; Ortolani, S.; Pinsonneault, M. H.; Plez, B.; Moroni, P. G. Prada; Pricopi, D.; Recio-Blanco, A.; Reylé, C.; Robin, A.; Roxburgh, I. W.; Salaris, M.; Santiago, B. X.; Schiavon, R.; Serenelli, A.; Sharma, S.; Aguirre, V. Silva; Soubiran, C.; Steinmetz, M.; Stello, D.; Strassmeier, K. G.; Ventura, P.; Ventura, R.; Walton, N. A.; Worley, C. C. Bibcode: 2017AN....338..644M Altcode: 2017arXiv170603778M Deciphering the assembly history of the Milky Way is a formidable task, which becomes possible only if one can produce high-resolution chrono-chemo-kinematical maps of the Galaxy. Data from large-scale astrometric and spectroscopic surveys will soon provide us with a well-defined view of the current chemo-kinematical structure of the Milky Way, but will only enable a blurred view on the temporal sequence that led to the present-day Galaxy. As demonstrated by the (ongoing) exploitation of data from the pioneering photometric missions CoRoT, Kepler, and K2, asteroseismology provides the way forward: solar-like oscillating giants are excellent evolutionary clocks thanks to the availability of seismic constraints on their mass and to the tight age-initial-mass relation they adhere to. In this paper we identify five key outstanding questions relating to the formation and evolution of the Milky Way that will need precise and accurate ages for large samples of stars to be addressed, and we identify the requirements in terms of number of targets and the precision on the stellar properties that are needed to tackle such questions. By quantifying the asteroseismic yields expected from PLATO for red-giant stars, we demonstrate that these requirements are within the capabilities of the current instrument design, provided that observations are sufficiently long to identify the evolutionary state and allow robust and precise determination of acoustic-mode frequencies. This will allow us to harvest data of sufficient quality to reach a 10% precision in age. This is a fundamental pre-requisite to then reach the more ambitious goal of a similar level of accuracy, which will only be possible if we have to hand a careful appraisal of systematic uncertainties on age deriving from our limited understanding of stellar physics, a goal which conveniently falls within the main aims of PLATO's core science. Title: SOLARIS: Solar Sail Investigation of the Sun Authors: Appourchaux, Thierry; Auchère, Frédéric; Antonucci, Ester; Gizon, Laurent; MacDonald, Malcolm; Hara, Hirohisa; Sekii, Takashi; Moses, Daniel; Vourlidas, Angelos Bibcode: 2017arXiv170708193A Altcode: In this paper, we detail the scientific objectives and outline a strawman payload of the SOLAR sail Investigation of the Sun (SOLARIS). The science objectives are to study the 3D structure of the solar magnetic and velocity field, the variation of total solar irradiance with latitude, and the structure of the corona. We show how we can meet these science objective using solar-sail technologies currently under development. We provide a tentative mission profile considering several trade-off approaches. We also provide a tentative mass budget breakdown and a perspective for a programmatic implementation. Title: Kepler observations of the asteroseismic binary HD 176465 Authors: White, T. R.; Benomar, O.; Silva Aguirre, V.; Ball, W. H.; Bedding, T. R.; Chaplin, W. J.; Christensen-Dalsgaard, J.; Garcia, R. A.; Gizon, L.; Stello, D.; Aigrain, S.; Antia, H. M.; Appourchaux, T.; Bazot, M.; Campante, T. L.; Creevey, O. L.; Davies, G. R.; Elsworth, Y. P.; Gaulme, P.; Handberg, R.; Hekker, S.; Houdek, G.; Howe, R.; Huber, D.; Karoff, C.; Marques, J. P.; Mathur, S.; McQuillan, A.; Metcalfe, T. S.; Mosser, B.; Nielsen, M. B.; Régulo, C.; Salabert, D.; Stahn, T. Bibcode: 2017A&A...601A..82W Altcode: 2016arXiv160909581W; 2016A&A...601A..82W Binary star systems are important for understanding stellar structure and evolution, and are especially useful when oscillations can be detected and analysed with asteroseismology. However, only four systems are known in which solar-like oscillations are detected in both components. Here, we analyse the fifth such system, HD 176465, which was observed by Kepler. We carefully analysed the system's power spectrum to measure individual mode frequencies, adapting our methods where necessary to accommodate the fact that both stars oscillate in a similar frequency range. We also modelled the two stars independently by fitting stellar models to the frequencies and complementaryparameters. We are able to cleanly separate the oscillation modes in both systems. The stellar models produce compatible ages and initial compositions for the stars, as is expected from their common and contemporaneous origin. Combining the individual ages, the system is about 3.0 ± 0.5 Gyr old. The two components of HD 176465 are young physically-similar oscillating solar analogues, the first such system to be found, and provide important constraints for stellar evolution and asteroseismology. Title: Future Mission Concepts for Helioseismology Authors: Sekii, Takashi; Appourchaux, Thierry; Fleck, Bernhard; Turck-Chièze, Sylvaine Bibcode: 2017hdsi.book..291S Altcode: No abstract at ADS Title: Helioseismology with Solar Orbiter Authors: Löptien, Björn; Birch, Aaron C.; Gizon, Laurent; Schou, Jesper; Appourchaux, Thierry; Blanco Rodríguez, Julián; Cally, Paul S.; Dominguez-Tagle, Carlos; Gandorfer, Achim; Hill, Frank; Hirzberger, Johann; Scherrer, Philip H.; Solanki, Sami K. Bibcode: 2017hdsi.book..257L Altcode: No abstract at ADS Title: A Distant Mirror: Solar Oscillations Observed on Neptune by the Kepler K2 Mission Authors: Gaulme, P.; Rowe, J. F.; Bedding, T. R.; Benomar, O.; Corsaro, E.; Davies, G. R.; Hale, S. J.; Howe, R.; Garcia, R. A.; Huber, D.; Jiménez, A.; Mathur, S.; Mosser, B.; Appourchaux, T.; Boumier, P.; Jackiewicz, J.; Leibacher, J.; Schmider, F. -X.; Hammel, H. B.; Lissauer, J. J.; Marley, M. S.; Simon, A. A.; Chaplin, W. J.; Elsworth, Y.; Guzik, J. A.; Murphy, N.; Silva Aguirre, V. Bibcode: 2016ApJ...833L..13G Altcode: 2016arXiv161204287G Starting in 2014 December, Kepler K 2 observed Neptune continuously for 49 days at a 1 minute cadence. The goals consisted of studying its atmospheric dynamics, detecting its global acoustic oscillations, and those of the Sun, which we report on here. We present the first indirect detection of solar oscillations in intensity measurements. Beyond the remarkable technical performance, it indicates how Kepler would see a star like the Sun. The result from the global asteroseismic approach, which consists of measuring the oscillation frequency at maximum amplitude ν max and the mean frequency separation between mode overtones Δν, is surprising as the ν max measured from Neptune photometry is larger than the accepted value. Compared to the usual reference ν max,⊙ = 3100 μHz, the asteroseismic scaling relations therefore make the solar mass and radius appear larger by 13.8 ± 5.8% and 4.3 ± 1.9%, respectively. The higher ν max is caused by a combination of the value of ν max,⊙, being larger at the time of observations than the usual reference from SOHO/VIRGO/SPM data (3160 ± 10 μHz), and the noise level of the K 2 time series, being 10 times larger than VIRGO’s. The peak-bagging method provides more consistent results: despite a low signal-to-noise ratio (S/N), we model 10 overtones for degrees ℓ = 0, 1, 2. We compare the K 2 data with simultaneous SOHO/VIRGO/SPM photometry and BiSON velocity measurements. The individual frequencies, widths, and amplitudes mostly match those from VIRGO and BiSON within 1σ, except for the few peaks with the lowest S/N. Title: Far side Helioseismology with Solar Orbiter Authors: Appourchaux, T.; Birch, A.; Gizon, L. C.; Löptien, B.; Schou, J.; Solanki, S. K.; del Toro Iniesta, J. C.; Gandorfer, A.; Hirzberger, J.; Alvarez-Herrero, A.; Woch, J. G.; Schmidt, W. Bibcode: 2016AGUFMSH43A2554A Altcode: The Solar Orbiter mission, to be launched in October 2018, will carry a suite of remote sensing and in-situ instruments, including the Polarimetric and Helioseismic Imager (PHI). PHI will deliver high-cadence images of the Sun in intensity and Doppler velocity suitable for carrying out novel helioseismic studies. The orbit of the Solar Orbiter spacecraft will reach a solar latitude up to 34 degrees by the end of the extended mission and thus will enable the first local helioseismology studies of the polar regions. The full range of Earth-Sun-spacecraft angles provided by the orbit will enable helioseismology from two vantage points by combining PHI with another instrument: stereoscopic helioseismology will allow the study of the deep solar interior and a better understanding of the physics of solar oscillations in both quiet Sun and sunspots. In this paper we will review the helioseismic objectives achievable with PHI, and will also give a short status report of the development of the Flight Model of PHI. Title: Detection of Solar-like Oscillations, Observational Constraints, and Stellar Models for θ Cyg, the Brightest Star Observed By the Kepler Mission Authors: Guzik, J. A.; Houdek, G.; Chaplin, W. J.; Smalley, B.; Kurtz, D. W.; Gilliland, R. L.; Mullally, F.; Rowe, J. F.; Bryson, S. T.; Still, M. D.; Antoci, V.; Appourchaux, T.; Basu, S.; Bedding, T. R.; Benomar, O.; Garcia, R. A.; Huber, D.; Kjeldsen, H.; Latham, D. W.; Metcalfe, T. S.; Pápics, P. I.; White, T. R.; Aerts, C.; Ballot, J.; Boyajian, T. S.; Briquet, M.; Bruntt, H.; Buchhave, L. A.; Campante, T. L.; Catanzaro, G.; Christensen-Dalsgaard, J.; Davies, G. R.; Doğan, G.; Dragomir, D.; Doyle, A. P.; Elsworth, Y.; Frasca, A.; Gaulme, P.; Gruberbauer, M.; Handberg, R.; Hekker, S.; Karoff, C.; Lehmann, H.; Mathias, P.; Mathur, S.; Miglio, A.; Molenda-Żakowicz, J.; Mosser, B.; Murphy, S. J.; Régulo, C.; Ripepi, V.; Salabert, D.; Sousa, S. G.; Stello, D.; Uytterhoeven, K. Bibcode: 2016ApJ...831...17G Altcode: 2016arXiv160701035G θ Cygni is an F3 spectral type magnitude V = 4.48 main-sequence star that was the brightest star observed by the original Kepler spacecraft mission. Short-cadence (58.8 s) photometric data using a custom aperture were first obtained during Quarter 6 (2010 June-September) and subsequently in Quarters 8 and 12-17. We present analyses of solar-like oscillations based on Q6 and Q8 data, identifying angular degree l = 0, 1, and 2 modes with frequencies of 1000-2700 μHz, a large frequency separation of 83.9 ± 0.4 μHz, and maximum oscillation amplitude at frequency ν max = 1829 ± 54 μHz. We also present analyses of new ground-based spectroscopic observations, which, combined with interferometric angular diameter measurements, give T eff = 6697 ± 78 K, radius 1.49 ± 0.03 R ⊙, [Fe/H] = -0.02 ± 0.06 dex, and log g = 4.23 ± 0.03. We calculate stellar models matching these constraints using the Yale Rotating Evolution Code and the Asteroseismic Modeling Portal. The best-fit models have masses of 1.35-1.39 M ⊙ and ages of 1.0-1.6 Gyr. θ Cyg’s T eff and log g place it cooler than the red edge of the γ Doradus instability region established from pre-Kepler ground-based observations, but just at the red edge derived from pulsation modeling. The pulsation models show γ Dor gravity modes driven by the convective blocking mechanism, with frequencies of 1-3 cycles per day (11 to 33 μHz). However, gravity modes were not seen in Kepler data; one signal at 1.776 cycles per day (20.56 μHz) may be attributable to a faint, possibly background, binary. Title: Oscillation mode linewidths and heights of 23 main-sequence stars observed by Kepler (Corrigendum) Authors: Appourchaux, T.; Antia, H. M.; Benomar, O.; Campante, T. L.; Davies, G. R.; Handberg, R.; Howe, R.; Régulo, C.; Belkacem, K.; Houdek, G.; García, R. A.; Chaplin, W. J. Bibcode: 2016A&A...595C...2A Altcode: No abstract at ADS Title: The Asteroseismic Potential of TESS: Exoplanet-host Stars Authors: Campante, T. L.; Schofield, M.; Kuszlewicz, J. S.; Bouma, L.; Chaplin, W. J.; Huber, D.; Christensen-Dalsgaard, J.; Kjeldsen, H.; Bossini, D.; North, T. S. H.; Appourchaux, T.; Latham, D. W.; Pepper, J.; Ricker, G. R.; Stassun, K. G.; Vanderspek, R.; Winn, J. N. Bibcode: 2016ApJ...830..138C Altcode: 2016arXiv160801138C New insights on stellar evolution and stellar interior physics are being made possible by asteroseismology. Throughout the course of the Kepler mission, asteroseismology has also played an important role in the characterization of exoplanet-host stars and their planetary systems. The upcoming NASA Transiting Exoplanet Survey Satellite (TESS) will be performing a near all-sky survey for planets that transit bright nearby stars. In addition, its excellent photometric precision, combined with its fine time sampling and long intervals of uninterrupted observations, will enable asteroseismology of solar-type and red-giant stars. Here we develop a simple test to estimate the detectability of solar-like oscillations in TESS photometry of any given star. Based on an all-sky stellar and planetary synthetic population, we go on to predict the asteroseismic yield of the TESS mission, placing emphasis on the yield of exoplanet-host stars for which we expect to detect solar-like oscillations. This is done for both the target stars (observed at a 2-minute cadence) and the full-frame-image stars (observed at a 30-minute cadence). A similar exercise is also conducted based on a compilation of known host stars. We predict that TESS will detect solar-like oscillations in a few dozen target hosts (mainly subgiant stars but also in a smaller number of F dwarfs), in up to 200 low-luminosity red-giant hosts, and in over 100 solar-type and red-giant known hosts, thereby leading to a threefold improvement in the asteroseismic yield of exoplanet-host stars when compared to Kepler's. Title: Advances in the development of a Mach-Zehnder interferometric Doppler imager for seismology of giant planets Authors: Gonçalves, Ivan; Schmider, François-Xavier; Bresson, Yves; Dejonghe, Julien; Preis, Olivier; Robbe-Dubois, Sylvie; Appourchaux, Thierry; Boumier, Patrick; Leclec'h, Jean-Christophe; Morinaud, Gilles; Gaulme, Patrick; Jackiewicz, Jason Bibcode: 2016SPIE.9908E..3MG Altcode: The measurements of radial velocity fields on planets with a Doppler Spectro-Imager allow the study of atmospheric dynamics of giant planets and the detection of their acoustic oscillations. The frequencies of these oscillations lead to the determination of the internal structure by asteroseismology. A new imaging tachometer, based on a Mach-Zehnder interferometer, has been developed to monitor the Doppler shift of solar lines reflected at the surface of the planets. We present the principle of this instrument. A prototype was designed and built, following the specifications of a future space mission. The performance of the prototype, both at the laboratory and on the sky, is presented here. Title: Measuring the extent of convective cores in low-mass stars using Kepler data: toward a calibration of core overshooting Authors: Deheuvels, S.; Brandão, I.; Silva Aguirre, V.; Ballot, J.; Michel, E.; Cunha, M. S.; Lebreton, Y.; Appourchaux, T. Bibcode: 2016A&A...589A..93D Altcode: 2016arXiv160302332D Context. Our poor understanding of the boundaries of convective cores generates large uncertainties on the extent of these cores and thus on stellar ages. The detection and precise characterization of solar-like oscillations in hundreds of main-sequence stars by CoRoT and Kepler has given the opportunity to revisit this problem.
Aims: Our aim is to use asteroseismology to consistently measure the extent of convective cores in a sample of main-sequence stars whose masses lie around the mass limit for having a convective core.
Methods: We first tested and validated a seismic diagnostic that was proposed to probe the extent of convective cores in a model-dependent way using the so-called r010 ratios, which are built with l = 0 and l = 1 modes. We applied this procedure to 24 low-mass stars chosen among Kepler targets to optimize the efficiency of this diagnostic. For this purpose, we computed grids of stellar models with both the Cesam2k and mesa evolution codes, where the extensions of convective cores were modeled either by an instantaneous mixing or as a diffusion process.
Results: We found that 10 stars in our sample are in fact subgiants. Among the other targets, were able to unambiguously detect convective cores in eight stars, and we obtained seismic measurements of the extent of the mixed core in these targets with a good agreement between the Cesam2k and mesa codes. By performing optimizations using the Levenberg-Marquardt algorithm, we then obtained estimates of the amount of extra mixing beyond the core that is required in Cesam2k to reproduce seismic observations for these eight stars, and we showed that this can be used to propose a calibration of this quantity. This calibration depends on the prescription chosen for the extra mixing, but we found that it should also be valid for the code mesa, provided the same prescription is used.
Conclusions: This study constitutes a first step toward calibrating the extension of convective cores in low-mass stars, which will help reduce the uncertainties on the ages of these stars. Title: Helioseismology with Solar Orbiter Authors: Löptien, Björn; Birch, Aaron C.; Gizon, Laurent; Schou, Jesper; Appourchaux, Thierry; Blanco Rodríguez, Julián; Cally, Paul S.; Dominguez-Tagle, Carlos; Gandorfer, Achim; Hill, Frank; Hirzberger, Johann; Scherrer, Philip H.; Solanki, Sami K. Bibcode: 2015SSRv..196..251L Altcode: 2014arXiv1406.5435L; 2014SSRv..tmp...31L The Solar Orbiter mission, to be launched in July 2017, will carry a suite of remote sensing and in-situ instruments, including the Polarimetric and Helioseismic Imager (PHI). PHI will deliver high-cadence images of the Sun in intensity and Doppler velocity suitable for carrying out novel helioseismic studies. The orbit of the Solar Orbiter spacecraft will reach a solar latitude of up to 21∘ (up to 34∘ by the end of the extended mission) and thus will enable the first local helioseismology studies of the polar regions. Here we consider an array of science objectives to be addressed by helioseismology within the baseline telemetry allocation (51 Gbit per orbit, current baseline) and within the science observing windows (baseline 3×10 days per orbit). A particularly important objective is the measurement of large-scale flows at high latitudes (rotation and meridional flow), which are largely unknown but play an important role in flux transport dynamos. For both helioseismology and feature tracking methods convection is a source of noise in the measurement of longitudinally averaged large-scale flows, which decreases as T -1/2 where T is the total duration of the observations. Therefore, the detection of small amplitude signals (e.g., meridional circulation, flows in the deep solar interior) requires long observation times. As an example, one hundred days of observations at lower spatial resolution would provide a noise level of about three m/s on the meridional flow at 80∘ latitude. Longer time-series are also needed to study temporal variations with the solar cycle. The full range of Earth-Sun-spacecraft angles provided by the orbit will enable helioseismology from two vantage points by combining PHI with another instrument: stereoscopic helioseismology will allow the study of the deep solar interior and a better understanding of the physics of solar oscillations in both quiet Sun and sunspots. We have used a model of the PHI instrument to study its performance for helioseismology applications. As input we used a 6 hr time-series of realistic solar magneto-convection simulation (Stagger code) and the SPINOR radiative transfer code to synthesize the observables. The simulated power spectra of solar oscillations show that the instrument is suitable for helioseismology. In particular, the specified point spread function, image jitter, and photon noise are no obstacle to a successful mission. Title: Future Mission Concepts for Helioseismology Authors: Sekii, Takashi; Appourchaux, Thierry; Fleck, Bernhard; Turck-Chièze, Sylvaine Bibcode: 2015SSRv..196..285S Altcode: 2015SSRv..tmp...15S Future space-mission concepts currently discussed in the helioseismology community are reviewed. One popular idea is to observe the Sun from high latitudes, to explore the polar regions as well as to probe the deep interior using stereoscopic techniques, by combining observations from high latitudes with observations from within the ecliptic plane. Another idea is to stay within the ecliptic plane but still aim for stereoscopic helioseismology for deep layers. A new instrument and a novel mission concept for studying the solar core regions are also discussed. Title: A seismic and gravitationally bound double star observed by Kepler. Implication for the presence of a convective core Authors: Appourchaux, T.; Antia, H. M.; Ball, W.; Creevey, O.; Lebreton, Y.; Verma, K.; Vorontsov, S.; Campante, T. L.; Davies, G. R.; Gaulme, P.; Régulo, C.; Horch, E.; Howell, S.; Everett, M.; Ciardi, D.; Fossati, L.; Miglio, A.; Montalbán, J.; Chaplin, W. J.; García, R. A.; Gizon, L. Bibcode: 2015A&A...582A..25A Altcode: Context. Solar-like oscillations have been observed by Kepler and CoRoT in many solar-type stars, thereby providing a way to probe stars using asteroseismology.
Aims: The derivation of stellar parameters has usually been done with single stars. The aim of the paper is to derive the stellar parameters of a double-star system (HIP 93511), for which an interferometric orbit has been observed along with asteroseismic measurements.
Methods: We used a time series of nearly two years of data for the double star to detect the two oscillation-mode envelopes that appear in the power spectrum. Using a new scaling relation based on luminosity, we derived the radius and mass of each star. We derived the age of each star using two proxies: one based upon the large frequency separation and a new one based upon the small frequency separation. Using stellar modelling, the mode frequencies allowed us to derive the radius, the mass, and the age of each component. In addition, speckle interferometry performed since 2006 has enabled us to recover the orbit of the system and the total mass of the system.
Results: From the determination of the orbit, the total mass of the system is 2.34-0.33+0.45 M⊙. The total seismic mass using scaling relations is 2.47 ± 0.07 M⊙. The seismic age derived using the new proxy based upon the small frequency separation is 3.5 ± 0.3 Gyr. Based on stellar modelling, the mean common age of the system is 2.7-3.9 Gyr. The mean total seismic mass of the system is 2.34-2.53 M⊙ consistent with what we determined independently with the orbit. The stellar models provide the mean radius, mass, and age of the stars as RA = 1.82-1.87R⊙, MA = 1.25-1.39 M⊙, AgeA = 2.6-3.5 Gyr; RB = 1.22-1.25 R⊙, MB = 1.08-1.14 M⊙, AgeB = 3.35-4.21 Gyr. The models provide two sets of values for Star A: [1.25-1.27] M⊙ and [1.34-1.39] M⊙. We detect a convective core in Star A, while Star B does not have any. For the metallicity of the binary system of Z ≈ 0.02, we set the limit between stars having a convective core in the range [1.14-1.25] M⊙.

Appendices are available in electronic form at http://www.aanda.org Title: The Polarimetric and Helioseismic Imager for Solar Orbiter: SO/PHI Authors: Solanki, Sami K.; del Toro Iniesta, Jose Carlos; Woch, Joachim; Gandorfer, Achim; Hirzberger, Johann; Schmidt, Wolfgang; Appourchaux, Thierry; Alvarez-Herrero, Alberto Bibcode: 2015IAUS..305..108S Altcode: 2015arXiv150203368S The Solar Orbiter is the next solar physics mission of the European Space Agency, ESA, in collaboration with NASA, with a launch planned in 2018. The spacecraft is designed to approach the Sun to within 0.28 AU at perihelion of a highly eccentric orbit. The proximity with the Sun will also allow its observation at uniformly high resolution at EUV and visible wavelengths. Such observations are central for learning more about the magnetic coupling of the solar atmosphere. At a later phase in the mission the spacecraft will leave the ecliptic and study the enigmatic poles of the Sun from a heliographic latitude of up to 33°. Title: Asteroseismology of Solar-Type Stars with K2: Detection of Oscillations in C1 Data Authors: Chaplin, W. J.; Lund, M. N.; Handberg, R.; Basu, S.; Buchhave, L. A.; Campante, T. L.; Davies, G. R.; Huber, D.; Latham, D. W.; Latham, C. A.; Serenelli, A.; Antia, H. M.; Appourchaux, T.; Ball, W. H.; Benomar, O.; Casagrande, L.; Christensen-Dalsgaard, J.; Coelho, H. R.; Creevey, O. L.; Elsworth, Y.; García, R. A.; Gaulme, P.; Hekker, S.; Kallinger, T.; Karoff, C.; Kawaler, S. D.; Kjeldsen, H.; Lundkvist, M. S.; Marcadon, F.; Mathur, S.; Miglio, A.; Mosser, B.; Régulo, C.; Roxburgh, I. W.; Silva Aguirre, V.; Stello, D.; Verma, K.; White, T. R.; Bedding, T. R.; Barclay, T.; Buzasi, D. L.; Dehuevels, S.; Gizon, L.; Houdek, G.; Howell, S. B.; Salabert, D.; Soderblom, D. R. Bibcode: 2015PASP..127.1038C Altcode: 2015arXiv150701827C We present the first detections by the NASA K2 Mission of oscillations in solar-type stars, using short-cadence data collected during K2 Campaign\,1 (C1). We understand the asteroseismic detection thresholds for C1-like levels of photometric performance, and we can detect oscillations in subgiants having dominant oscillation frequencies around $1000\,\rm \mu Hz$. Changes to the operation of the fine-guidance sensors are expected to give significant improvements in the high-frequency performance from C3 onwards. A reduction in the excess high-frequency noise by a factor of two-and-a-half in amplitude would bring main-sequence stars with dominant oscillation frequencies as high as ${\simeq 2500}\,\rm \mu Hz$ into play as potential asteroseismic targets for K2. Title: Asteroseismic estimate of helium abundance of 16 Cyg A, B Authors: Verma, Kuldeep; Faria, João P.; Antia, H. M.; Basu, Sarbani; Mazumdar, Anwesh; Monteiro, Mário J. P. F. G.; Appourchaux, Thierry; Chaplin, William J.; García, Rafael A.; Metcalfe, Travis S. Bibcode: 2015EPJWC.10106066V Altcode: The helium ionization zone in a star leaves a characteristic signature on its oscillation frequencies, which can be used to estimate the helium content in the envelope of the star. We use the oscillation frequencies of 16 Cyg A and B, obtained using 2.5 years of Kepler data, to estimate the envelope helium abundance of these stars. We find the envelope helium abundance to lie in the range 0.231-0.251 for 16 Cyg A and 0.218-0.266 for 16 Cyg B. Title: An attempt to calibrate core overshooting using the seismic properties of low-mass stars Authors: Deheuvels, S.; Silva Aguirre, V.; Cunha, M. S.; Appourchaux, T.; Ballot, J.; Brandão, I.; Lebreton, Y.; Michel, E. Bibcode: 2015EPJWC.10101013D Altcode: The sizes of stellar convective cores remain uncertain because of our poor understanding of the interface between convective and radiative zones. The very high precision of the seismic data provided by the CoRoT and Kepler space missions offers a great opportunity to search for the signature of convective cores in main-sequence stars. We here validate the seismic diagnostic based on the r010 ratios, which has been proposed to probe the size of convective cores, and we use it on a sample of 24 specially chosen Kepler targets. We thus constrain the extension of the core in 14 targets and find a tendency of the core extension to increase with stellar mass in this mass range. These results will be presented in more detail in a paper in preparation. Title: Helioseismology: Observations and space missions Authors: Pallé, P. L.; Appourchaux, T.; Christensen-Dalsgaard, J.; Garcxía, I. A. Bibcode: 2015exse.book...25P Altcode: No abstract at ADS Title: Asteroseismology observations and space missions Authors: Appourchaux, T.; Grundahl, F. Bibcode: 2015exse.book...11A Altcode: No abstract at ADS Title: Asteroseismic inference on rotation, gyrochronology and planetary system dynamics of 16 Cygni Authors: Davies, G. R.; Chaplin, W. J.; Farr, W. M.; García, R. A.; Lund, M. N.; Mathis, S.; Metcalfe, T. S.; Appourchaux, T.; Basu, S.; Benomar, O.; Campante, T. L.; Ceillier, T.; Elsworth, Y.; Handberg, R.; Salabert, D.; Stello, D. Bibcode: 2015MNRAS.446.2959D Altcode: 2014arXiv1411.1359D The solar analogues 16 Cyg A and B are excellent asteroseismic targets in the Kepler field of view and together with a red dwarf and a Jovian planet form an interesting system. For these more evolved Sun-like stars we cannot detect surface rotation with the current Kepler data but instead use the technique of asteroseimology to determine rotational properties of both 16 Cyg A and B. We find the rotation periods to be 23.8^{+1.5}_{-1.8} and 23.2^{+11.5}_{-3.2} d, and the angles of inclination to be 56^{+6}_{-5}° and 36^{+17}_{-7}°, for A and B, respectively. Together with these results we use the published mass and age to suggest that, under the assumption of a solar-like rotation profile, 16 Cyg A could be used when calibrating gyrochronology relations. In addition, we discuss the known 16 Cyg B star-planet eccentricity and measured low obliquity which is consistent with Kozai cycling and tidal theory. Title: Building galaxies, stars, planets and the ingredients for life between the stars. The science behind the European Ultraviolet-Visible Observatory Authors: Gómez de Castro, Ana I.; Appourchaux, Thierry; Barstow, Martin A.; Barthelemy, Mathieu; Baudin, Frederic; Benetti, Stefano; Blay, Pere; Brosch, Noah; Bunce, Emma; de Martino, Domitilla; Deharveng, Jean-Michel; Ferlet, Roger; France, Kevin; García, Miriam; Gänsicke, Boris; Gry, Cecile; Hillenbrand, Lynne; Josselin, Eric; Kehrig, Carolina; Lamy, Laurent; Lapington, Jon; Lecavelier des Etangs, Alain; LePetit, Frank; López-Santiago, Javier; Milliard, Bruno; Monier, Richard; Naletto, Giampiero; Nazé, Yael; Neiner, Coralie; Nichols, Jonathan; Orio, Marina; Pagano, Isabella; Peroux, Céline; Rauw, Gregor; Shore, Steven; Spaans, Marco; Tovmassian, Gagik; ud-Doula, Asif; Vilchez, José Bibcode: 2014Ap&SS.354..229G Altcode: 2014Ap&SS.tmp..185G; 2013arXiv1306.3358G This contribution gathers the contents of the white paper submitted by the UV community to the Call issued by the European Space Agency in March 2013, for the definition of the L2 and L3 missions in the ESA science program. We outlined the key science that a large UV facility would make possible and the instrumentation to be implemented. The growth of luminous structures and the building blocks of life in the Universe began as primordial gas was processed in stars and mixed at galactic scales. The mechanisms responsible for this development are not well-understood and have changed over the intervening 13 billion years. To follow the evolution of matter over cosmic time, it is necessary to study the strongest (resonance) transitions of the most abundant species in the Universe. Most of them are in the ultraviolet (UV; 950 Å-3000 Å) spectral range that is unobservable from the ground. A versatile space observatory with UV sensitivity a factor of 50-100 greater than existing facilities will revolutionize our understanding of the Universe. Habitable planets grow in protostellar discs under ultraviolet irradiation, a by-product of the star-disk interaction that drives the physical and chemical evolution of discs and young planetary systems. The electronic transitions of the most abundant molecules are pumped by this UV field, providing unique diagnostics of the planet-forming environment that cannot be accessed from the ground. Earth's atmosphere is in constant interaction with the interplanetary medium and the solar UV radiation field. A 50-100 times improvement in sensitivity would enable the observation of the key atmospheric ingredients of Earth-like exoplanets (carbon, oxygen, ozone), provide crucial input for models of biologically active worlds outside the solar system, and provide the phenomenological baseline to understand the Earth atmosphere in context. Title: The PLATO 2.0 mission Authors: Rauer, H.; Catala, C.; Aerts, C.; Appourchaux, T.; Benz, W.; Brandeker, A.; Christensen-Dalsgaard, J.; Deleuil, M.; Gizon, L.; Goupil, M. -J.; Güdel, M.; Janot-Pacheco, E.; Mas-Hesse, M.; Pagano, I.; Piotto, G.; Pollacco, D.; Santos, Ċ.; Smith, A.; Suárez, J. -C.; Szabó, R.; Udry, S.; Adibekyan, V.; Alibert, Y.; Almenara, J. -M.; Amaro-Seoane, P.; Eiff, M. Ammler-von; Asplund, M.; Antonello, E.; Barnes, S.; Baudin, F.; Belkacem, K.; Bergemann, M.; Bihain, G.; Birch, A. C.; Bonfils, X.; Boisse, I.; Bonomo, A. S.; Borsa, F.; Brandão, I. M.; Brocato, E.; Brun, S.; Burleigh, M.; Burston, R.; Cabrera, J.; Cassisi, S.; Chaplin, W.; Charpinet, S.; Chiappini, C.; Church, R. P.; Csizmadia, Sz.; Cunha, M.; Damasso, M.; Davies, M. B.; Deeg, H. J.; Díaz, R. F.; Dreizler, S.; Dreyer, C.; Eggenberger, P.; Ehrenreich, D.; Eigmüller, P.; Erikson, A.; Farmer, R.; Feltzing, S.; de Oliveira Fialho, F.; Figueira, P.; Forveille, T.; Fridlund, M.; García, R. A.; Giommi, P.; Giuffrida, G.; Godolt, M.; Gomes da Silva, J.; Granzer, T.; Grenfell, J. L.; Grotsch-Noels, A.; Günther, E.; Haswell, C. A.; Hatzes, A. P.; Hébrard, G.; Hekker, S.; Helled, R.; Heng, K.; Jenkins, J. M.; Johansen, A.; Khodachenko, M. L.; Kislyakova, K. G.; Kley, W.; Kolb, U.; Krivova, N.; Kupka, F.; Lammer, H.; Lanza, A. F.; Lebreton, Y.; Magrin, D.; Marcos-Arenal, P.; Marrese, P. M.; Marques, J. P.; Martins, J.; Mathis, S.; Mathur, S.; Messina, S.; Miglio, A.; Montalban, J.; Montalto, M.; Monteiro, M. J. P. F. G.; Moradi, H.; Moravveji, E.; Mordasini, C.; Morel, T.; Mortier, A.; Nascimbeni, V.; Nelson, R. P.; Nielsen, M. B.; Noack, L.; Norton, A. J.; Ofir, A.; Oshagh, M.; Ouazzani, R. -M.; Pápics, P.; Parro, V. C.; Petit, P.; Plez, B.; Poretti, E.; Quirrenbach, A.; Ragazzoni, R.; Raimondo, G.; Rainer, M.; Reese, D. R.; Redmer, R.; Reffert, S.; Rojas-Ayala, B.; Roxburgh, I. W.; Salmon, S.; Santerne, A.; Schneider, J.; Schou, J.; Schuh, S.; Schunker, H.; Silva-Valio, A.; Silvotti, R.; Skillen, I.; Snellen, I.; Sohl, F.; Sousa, S. G.; Sozzetti, A.; Stello, D.; Strassmeier, K. G.; Švanda, M.; Szabó, Gy. M.; Tkachenko, A.; Valencia, D.; Van Grootel, V.; Vauclair, S. D.; Ventura, P.; Wagner, F. W.; Walton, N. A.; Weingrill, J.; Werner, S. C.; Wheatley, P. J.; Zwintz, K. Bibcode: 2014ExA....38..249R Altcode: 2014ExA...tmp...41R; 2013arXiv1310.0696R PLATO 2.0 has recently been selected for ESA's M3 launch opportunity (2022/24). Providing accurate key planet parameters (radius, mass, density and age) in statistical numbers, it addresses fundamental questions such as: How do planetary systems form and evolve? Are there other systems with planets like ours, including potentially habitable planets? The PLATO 2.0 instrument consists of 34 small aperture telescopes (32 with 25 s readout cadence and 2 with 2.5 s candence) providing a wide field-of-view (2232 deg 2) and a large photometric magnitude range (4-16 mag). It focusses on bright (4-11 mag) stars in wide fields to detect and characterize planets down to Earth-size by photometric transits, whose masses can then be determined by ground-based radial-velocity follow-up measurements. Asteroseismology will be performed for these bright stars to obtain highly accurate stellar parameters, including masses and ages. The combination of bright targets and asteroseismology results in high accuracy for the bulk planet parameters: 2 %, 4-10 % and 10 % for planet radii, masses and ages, respectively. The planned baseline observing strategy includes two long pointings (2-3 years) to detect and bulk characterize planets reaching into the habitable zone (HZ) of solar-like stars and an additional step-and-stare phase to cover in total about 50 % of the sky. PLATO 2.0 will observe up to 1,000,000 stars and detect and characterize hundreds of small planets, and thousands of planets in the Neptune to gas giant regime out to the HZ. It will therefore provide the first large-scale catalogue of bulk characterized planets with accurate radii, masses, mean densities and ages. This catalogue will include terrestrial planets at intermediate orbital distances, where surface temperatures are moderate. Coverage of this parameter range with statistical numbers of bulk characterized planets is unique to PLATO 2.0. The PLATO 2.0 catalogue allows us to e.g.: - complete our knowledge of planet diversity for low-mass objects, - correlate the planet mean density-orbital distance distribution with predictions from planet formation theories,- constrain the influence of planet migration and scattering on the architecture of multiple systems, and - specify how planet and system parameters change with host star characteristics, such as type, metallicity and age. The catalogue will allow us to study planets and planetary systems at different evolutionary phases. It will further provide a census for small, low-mass planets. This will serve to identify objects which retained their primordial hydrogen atmosphere and in general the typical characteristics of planets in such low-mass, low-density range. Planets detected by PLATO 2.0 will orbit bright stars and many of them will be targets for future atmosphere spectroscopy exploring their atmosphere. Furthermore, the mission has the potential to detect exomoons, planetary rings, binary and Trojan planets. The planetary science possible with PLATO 2.0 is complemented by its impact on stellar and galactic science via asteroseismology as well as light curves of all kinds of variable stars, together with observations of stellar clusters of different ages. This will allow us to improve stellar models and study stellar activity. A large number of well-known ages from red giant stars will probe the structure and evolution of our Galaxy. Asteroseismic ages of bright stars for different phases of stellar evolution allow calibrating stellar age-rotation relationships. Together with the results of ESA's Gaia mission, the results of PLATO 2.0 will provide a huge legacy to planetary, stellar and galactic science. Title: Filtergraph Calibration for the Polarimetric and Helioseismic Imager Authors: Dominguez-Tagle, Carlos; Appourchaux, Thierry; Fourmond, Jean-Jacques; Philippon, Anne; Le Clec'h, Jean-Christophe; Bouzit, Mehdi; Le Cocguen, Regis Bibcode: 2014JSAST..12.Tk25D Altcode: Solar Orbiter mission will study the Sun to the proximity of 0.28 AU, reaching solar latitudes up to 34°. This spacecraft will be launched in 2017 and will represent a complete approach to heliophysics. The Polarimetric and Helioseismic Imager (PHI), on board of Solar Orbiter, will provide the most important data for helioseismology. PHI will measure the photospheric vector magnetic field and the line-of-sight velocity observing the FeI 6173 A absorption line with a narrowband filtergraph (FG). At different spectral positions, the polarization state of the incoming light will be analyzed. The FG will provide a tuning range to compensate the spacecraft radial velocity and to scan the continuum at both sides of the absorption line. Thus, the fine tuning of the FG is essential for the instrument performance. Here we present the FG characterization and calibration status as they represent an important milestone in the development of the instrument. Title: Optical characterization of the breadboard narrowband prefilters for Solar Orbiter PHI Authors: Dominguez-Tagle, Carlos; Appourchaux, Thierry; Ruiz de Galarreta, Claudia; Fourmond, Jean-Jacques; Philippon, Anne; Le Clec'h, Jean-Christophe; Bouzit, Mehdi; Bommier, Véronique; Le Cocguen, Regis; Crussaire, Daniel; Malherbe, Jean-Marie Bibcode: 2014SPIE.9143E..5GD Altcode: The Polarimetric and Helioseismic Imager (PHI) on board of Solar Orbiter will observe the Sun to measure the photospheric vector magnetic field and the line-of-sight velocity. It will employ a narrowband filtergraph (FG) to scan the FeI 6173 Å absorption line. At different spectral positions, the polarization state of the incoming light will be analyzed. The FG will provide a tuning range to scan the line, the continuum, and to compensate for the spacecraft radial velocity, as it will approach to the Sun down to 0.28 AU. The FG includes a Fabry-Perot etalon and two narrowband prefilters. The bandpass of the narrowest one has a nominal Full Width at Half Maximum (FWHM) of 2.7 Å. The measurement of the prefilters characteristics is essential for the instrument calibration. Here we present the results of the breadboard prefilters characterization, which is an important milestone in the development of the instrument. Title: Asteroseismic Estimate of Helium Abundance of a Solar Analog Binary System Authors: Verma, Kuldeep; Faria, João P.; Antia, H. M.; Basu, Sarbani; Mazumdar, Anwesh; Monteiro, Mário J. P. F. G.; Appourchaux, Thierry; Chaplin, William J.; García, Rafael A.; Metcalfe, Travis S. Bibcode: 2014ApJ...790..138V Altcode: 2014arXiv1405.7512V 16 Cyg A and B are among the brightest stars observed by Kepler. What makes these stars more interesting is that they are solar analogs. 16 Cyg A and B exhibit solar-like oscillations. In this work we use oscillation frequencies obtained using 2.5 yr of Kepler data to determine the current helium abundance of these stars. For this we use the fact that the helium ionization zone leaves a signature on the oscillation frequencies and that this signature can be calibrated to determine the helium abundance of that layer. By calibrating the signature of the helium ionization zone against models of known helium abundance, the helium abundance in the envelope of 16 Cyg A is found to lie in the range of 0.231 to 0.251 and that of 16 Cyg B lies in the range of 0.218 to 0.266. Title: Oscillation mode linewidths and heights of 23 main-sequence stars observed by Kepler Authors: Appourchaux, T.; Antia, H. M.; Benomar, O.; Campante, T. L.; Davies, G. R.; Handberg, R.; Howe, R.; Régulo, C.; Belkacem, K.; Houdek, G.; García, R. A.; Chaplin, W. J. Bibcode: 2014A&A...566A..20A Altcode: 2014arXiv1403.7046A Context. Solar-like oscillations have been observed by Kepler and CoRoT in many solar-type stars, thereby providing a way to probe the stars using asteroseismology.
Aims: We provide the mode linewidths and mode heights of the oscillations of various stars as a function of frequency and of effective temperature.
Methods: We used a time series of nearly two years of data for each star. The 23 stars observed belong to the simple or F-like category. The power spectra of the 23 main-sequence stars were analysed using both maximum likelihood estimators and Bayesian estimators, providing individual mode characteristics such as frequencies, linewidths, and mode heights. We study the source of systematic errors in the mode linewidths and mode heights, and we present a way to correct these errors with respect to a common reference fit.
Results: Using the correction, we can explain all sources of systematic errors, which could be reduced to less than ±15% for mode linewidths and heights, and less than ±5% for amplitude, when compared to the reference fit. The effect of a different estimated stellar background and a different estimated splitting will provide frequency-dependent systematic errors that might affect the comparison with theoretical mode linewidth and mode height, therefore affecting the understanding of the physical nature of these parameters. All other sources of relative systematic errors are less dependent upon frequency. We also provide the dependence of the so-called linewidth dip in the middle of the observed frequency range as a function of effective temperature. We show that the depth of the dip decreases with increasing effective temperature. The dependence of the dip on effective temperature may imply that the mixing length parameter α or the convective flux may increase with effective temperature.

Tables 4-27 and Appendices are available in electronic form at http://www.aanda.org Title: Surface Activity and Oscillation Amplitudes of Red Giants in Eclipsing Binaries Authors: Gaulme, P.; Jackiewicz, J.; Appourchaux, T.; Mosser, B. Bibcode: 2014ApJ...785....5G Altcode: 2014arXiv1402.3027G Among the 19 red-giant stars belonging to eclipsing binary systems that have been identified in Kepler data, 15 display solar-like oscillations. We study whether the absence of mode detection in the remaining 4 is an observational bias or possibly evidence of mode damping that originates from tidal interactions. A careful analysis of the corresponding Kepler light curves shows that modes with amplitudes that are usually observed in red giants would have been detected if they were present. We observe that mode depletion is strongly associated with short-period systems, in which stellar radii account for 16%-24% of the semi-major axis, and where red-giant surface activity is detected. We suggest that when the rotational and orbital periods synchronize in close binaries, the red-giant component is spun up, so that a dynamo mechanism starts and generates a magnetic field, leading to observable stellar activity. Pressure modes would then be damped as acoustic waves dissipate in these fields. Title: Seismic analysis of HD 43587Aa, a solar-like oscillator in a multiple system Authors: Boumier, P.; Benomar, O.; Baudin, F.; Verner, G.; Appourchaux, T.; Lebreton, Y.; Gaulme, P.; Chaplin, W.; García, R. A.; Hekker, S.; Regulo, C.; Salabert, D.; Stahn, T.; Elsworth, Y.; Gizon, L.; Hall, M.; Mathur, S.; Michel, E.; Morel, T.; Mosser, B.; Poretti, E.; Rainer, M.; Roxburgh, I.; do Nascimento, J. -D., Jr.; Samadi, R.; Auvergne, M.; Chaintreuil, S.; Baglin, A.; Catala, C. Bibcode: 2014A&A...564A..34B Altcode: 2014arXiv1402.5053B Context. The object HD 43587Aa is a G0V star observed during the 145-day LRa03 run of the COnvection, ROtation and planetary Transits space mission (CoRoT), for which complementary High Accuracy Radial velocity Planet Searcher (HARPS) spectra with S/N > 300 were also obtained. Its visual magnitude is 5.71, and its effective temperature is close to 5950 K. It has a known companion in a highly eccentric orbit and is also coupled with two more distant companions.
Aims: We undertake a preliminary investigation of the internal structure of HD 43587Aa.
Methods: We carried out a seismic analysis of the star, using maximum likelihood estimators and Markov chain Monte Carlo methods.
Results: We established the first table of the eigenmode frequencies, widths, and heights for HD 43587Aa. The star appears to have a mass and a radius slightly larger than the Sun, and is slightly older (5.6 Gyr). Two scenarios are suggested for the geometry of the star: either its inclination angle is very low, or the rotation velocity of the star is very low.
Conclusions: A more detailed study of the rotation and of the magnetic and chromospheric activity for this star is needed, and will be the subject of a further study. New high resolution spectrometric observations should be performed for at least several months in duration. Title: Seismic constraints on the radial dependence of the internal rotation profiles of six Kepler subgiants and young red giants Authors: Deheuvels, S.; Doğan, G.; Goupil, M. J.; Appourchaux, T.; Benomar, O.; Bruntt, H.; Campante, T. L.; Casagrande, L.; Ceillier, T.; Davies, G. R.; De Cat, P.; Fu, J. N.; García, R. A.; Lobel, A.; Mosser, B.; Reese, D. R.; Regulo, C.; Schou, J.; Stahn, T.; Thygesen, A. O.; Yang, X. H.; Chaplin, W. J.; Christensen-Dalsgaard, J.; Eggenberger, P.; Gizon, L.; Mathis, S.; Molenda-Żakowicz, J.; Pinsonneault, M. Bibcode: 2014A&A...564A..27D Altcode: 2014arXiv1401.3096D Context. We still do not understand which physical mechanisms are responsible for the transport of angular momentum inside stars. The recent detection of mixed modes that contain the clear signature of rotation in the spectra of Kepler subgiants and red giants gives us the opportunity to make progress on this question.
Aims: Our aim is to probe the radial dependence of the rotation profiles for a sample of Kepler targets. For this purpose, subgiants and early red giants are particularly interesting targets because their rotational splittings are more sensitive to the rotation outside the deeper core than is the case for their more evolved counterparts.
Methods: We first extracted the rotational splittings and frequencies of the modes for six young Kepler red giants. We then performed a seismic modeling of these stars using the evolutionary codes Cesam2k and astec. By using the observed splittings and the rotational kernels of the optimal models, we inverted the internal rotation profiles of the six stars.
Results: We obtain estimates of the core rotation rates for these stars, and upper limits to the rotation in their convective envelope. We show that the rotation contrast between the core and the envelope increases during the subgiant branch. Our results also suggest that the core of subgiants spins up with time, while their envelope spins down. For two of the stars, we show that a discontinuous rotation profile with a deep discontinuity reproduces the observed splittings significantly better than a smooth rotation profile. Interestingly, the depths that are found to be most probable for the discontinuities roughly coincide with the location of the H-burning shell, which separates the layers that contract from those that expand.
Conclusions: We characterized the differential rotation pattern of six young giants with a range of metallicities, and with both radiative and convective cores on the main sequence. This will bring observational constraints to the scenarios of angular momentum transport in stars. Moreover, if the existence of sharp gradients in the rotation profiles of young red giants is confirmed, it is expected to help in distinguishing between the physical processes that could transport angular momentum in the subgiant and red giant branches.

Appendices and Tables 3-9 are available in electronic form at http://www.aanda.org Title: The PLATO 2.0 Mission Authors: Pagano, I.; Rauer, H.; Aerts, C.; Appourchaux, T.; Benz, W.; Brandeker, A.; Christensen-Dalsgaard, J.; Deleuil, M.; Gizon, L.; Goupil, M. -J.; Guedel, M.; Heras, A.; Janot-Pacheco, E.; Mas-Hesse, M.; Piotto, G.; Pollaco, D.; Ragazzoni, R.; Santos, N. C.; Smith, A.; Suarez, J. C.; Szabo, R.; Udry, S. Bibcode: 2014EPSC....9..789P Altcode: PLATO 2.0 is the M class mission selected by ESA for its M3 launch slot in the framework of the Cosmic Vision 2015-2025 program. The main goals of PLATO 2.0 are the detection of terrestrial exoplanets in the habitable zone of solar-type stars and the characterization of their bulk properties needed to determine their habitability. Moreover, PLATO 2.0 will be key in understanding the formation, architecture, and evolution of planetary systems thanks to a thorough inventory of the physical properties of thousands of rocky, icy, and gaseous giant planets. We will illustrate the PLATO 2.0 science goals, how the instrument is conceived to fulfil the science requirements, and how the project is organized to implement the instrument, plan the observations, and exploit the resulting data. Title: Prospects for Detecting Asteroseismic Binaries in Kepler Data Authors: Miglio, A.; Chaplin, W. J.; Farmer, R.; Kolb, U.; Girardi, L.; Elsworth, Y.; Appourchaux, T.; Handberg, R. Bibcode: 2014ApJ...784L...3M Altcode: 2014arXiv1402.2480M Asteroseismology may in principle be used to detect unresolved stellar binary systems comprised of solar-type stars and/or red giants. This novel method relies on the detection of the presence of two solar-like oscillation spectra in the frequency spectrum of a single light curve. Here, we make predictions of the numbers of systems that may be detectable in data already collected by the NASA Kepler Mission. Our predictions, which are based upon TRILEGAL and BiSEPS simulations of the Kepler field of view, indicate that as many as 200 or more "asteroseismic binaries" may be detectable in this manner. Most of these binaries should be comprised of two He-core-burning red giants. Owing largely to the limited numbers of targets with the requisite short-cadence Kepler data, we expect only a small number of detected binaries containing solar-type stars. The predicted yield of detections is sensitive to the assumed initial mass ratio distribution (IMRD) of the binary components and therefore represents a sensitive calibration of the much debated IMRD near mass ratio unity. Title: A crash course on data analysis in asteroseismology Authors: Appourchaux, Thierry Bibcode: 2014aste.book..123A Altcode: 2011arXiv1103.5352A In this course, I try to provide a few basics required for performing data analysis in asteroseismology. First, I address how one can properly treat times series: the sampling, the filtering effect, the use of Fourier transform, the associated statistics. Second, I address how one can apply statistics for decision making and for parameter estimation either in a frequentist of a Bayesian framework. Last, I review how these basic principle have been applied (or not) in asteroseismology. Title: VizieR Online Data Catalog: Asteroseismic study of solar-type stars (Chaplin+, 2014) Authors: Chaplin, W. J.; Basu, S.; Huber, D.; Serenelli, A.; Casagrande, L.; Silva Aguirre, V.; Ball, W. H.; Creevey, O. L.; Gizon, L.; Handberg, R.; Karoff, C.; Lutz, R.; Marques, J. P.; Miglio, A.; Stello, D.; Suran, M. D.; Pricopi, D.; Metcalfe, T. S.; Monteiro, M. J. P. F. G.; Molenda-Zakowicz, J.; Appourchaux, T.; Christensen-Dalsgaard, J.; Elsworth, Y.; Garcia, R. A.; Houdek, G.; Kjeldsen, H.; Bonanno, A.; Campante, T. L.; Corsaro, E.; Gaulme, P.; Hekker, S.; Mathur, S.; Mosser, B.; Regulo, C.; Salabert, D. Bibcode: 2014yCat..22100001C Altcode: During the first 10 months of science operations more than 2000 solar-type stars were selected by the Kepler Asteroseismic Science Consortium (KASC) to be observed as part of an asteroseismic survey of the Sun-like population in the Kepler field of view. Solar-like oscillations were detected by Kepler in more than 500 stars (Chaplin et al. 2011Sci...332..213C), and from these data robust global or average asteroseismic parameters were determined for all targets in the sample. These asteroseismic parameters allow us to estimate fundamental properties of the stars. In this paper we present stellar properties - namely masses, radii, surface gravities, mean densities and ages - of this asteroseismic sample of main-sequence and subgiant stars.

(5 data files). Title: Asteroseismic Fundamental Properties of Solar-type Stars Observed by the NASA Kepler Mission Authors: Chaplin, W. J.; Basu, S.; Huber, D.; Serenelli, A.; Casagrande, L.; Silva Aguirre, V.; Ball, W. H.; Creevey, O. L.; Gizon, L.; Handberg, R.; Karoff, C.; Lutz, R.; Marques, J. P.; Miglio, A.; Stello, D.; Suran, M. D.; Pricopi, D.; Metcalfe, T. S.; Monteiro, M. J. P. F. G.; Molenda-Żakowicz, J.; Appourchaux, T.; Christensen-Dalsgaard, J.; Elsworth, Y.; García, R. A.; Houdek, G.; Kjeldsen, H.; Bonanno, A.; Campante, T. L.; Corsaro, E.; Gaulme, P.; Hekker, S.; Mathur, S.; Mosser, B.; Régulo, C.; Salabert, D. Bibcode: 2014ApJS..210....1C Altcode: 2013arXiv1310.4001C We use asteroseismic data obtained by the NASA Kepler mission to estimate the fundamental properties of more than 500 main-sequence and sub-giant stars. Data obtained during the first 10 months of Kepler science operations were used for this work, when these solar-type targets were observed for one month each in survey mode. Stellar properties have been estimated using two global asteroseismic parameters and complementary photometric and spectroscopic data. Homogeneous sets of effective temperatures, T eff, were available for the entire ensemble from complementary photometry; spectroscopic estimates of T eff and [Fe/H] were available from a homogeneous analysis of ground-based data on a subset of 87 stars. We adopt a grid-based analysis, coupling six pipeline codes to 11 stellar evolutionary grids. Through use of these different grid-pipeline combinations we allow implicitly for the impact on the results of stellar model dependencies from commonly used grids, and differences in adopted pipeline methodologies. By using just two global parameters as the seismic inputs we are able to perform a homogenous analysis of all solar-type stars in the asteroseismic cohort, including many targets for which it would not be possible to provide robust estimates of individual oscillation frequencies (due to a combination of low signal-to-noise ratio and short dataset lengths). The median final quoted uncertainties from consolidation of the grid-based analyses are for the full ensemble (spectroscopic subset) approximately 10.8% (5.4%) in mass, 4.4% (2.2%) in radius, 0.017 dex (0.010 dex) in log g, and 4.3% (2.8%) in mean density. Around 36% (57%) of the stars have final age uncertainties smaller than 1 Gyr. These ages will be useful for ensemble studies, but should be treated carefully on a star-by-star basis. Future analyses using individual oscillation frequencies will offer significant improvements on up to 150 stars, in particular for estimates of the ages, where having the individual frequency data is most important. Title: On the development of a Fourier Transform Spectrometer for Solar Physics Authors: Ruiz de Galarreta, Claudia; Vial, Jean-Claude; Appourchaux, Thierry; Philippon, Anne Bibcode: 2014cosp...40E2793R Altcode: The origin and the evolution of the different structures that inhabit beyond the Sun’s photosphere, as well as the processes involved in the dynamics and the heating of the corona remain quite unknown. The inextricable complexity of the physical phenomena that govern the solar outer atmosphere is accompanied by the lack of suitable data adapted to the scientific need. Indeed, the interpretation and the models of the mechanisms that connect the exchanges between the chromosphere and the corona depend on critical observational parameters. It is for example essential to measure broad bands of vertical temperature and density ranges that fit the multiple spatial and temporal scales that are characteristic of the different events that take place in the Sun. The understanding of the dynamics of the plasma must be also based on the Doppler analysis of the observed scene. That implies the ability to combine time resolved spectroscopic and imaging technologies. Moreover, space is the place to observe the far UV corona and that implies a real technical challenge. Despite excellent advances in technology and instrumentation, the study of the Sun in the far UV is a fairly recent science. To date, no solar space mission could provide a combined and simultaneous diagnostic of both observables in the spectral range of interest. It is because of these expectations that the study of a new device called IFTSUV (the acronym of Imaging Fourier Transform Spectrometer working in the far UV) is presented in this paper. We start from the definition of the scientific requirements that lead to the technical choice, the first objective of this study is to develop a preliminary instrumental model of the IFTSUV. The overall technical and design specifications are based in theoretical calculations that have been expressed in terms of spectral accuracy, image quality and signal to noise ratio. Throughout the identification of difficult points, the realization of a servo-metrology system to control the sampling mirror appears naturally as an intrinsic need of proof of concept. Indeed, the wavenumbers from the raw spectra are set by the interferogram. That implies that acquisition must be rigorously constant and that the sampling steps must be known with high accuracy. Therefore, the mockup of a metrological solution that has been developped at IAS will is also presented. The results on the damonstrator that validate and converge to the optimization and prototyping of a system that could be integrated in a space based application will be discussed. Finally we propose a discussion on the possible future space mission opportunities in which this innovative project could be framed. Title: The History of the g-mode Quest Authors: Appourchaux, T.; Pallé, P. L. Bibcode: 2013ASPC..478..125A Altcode: 2013arXiv1309.3835A The quest for the solar gravity modes (or g modes) is key for the understanding of the structure and dynamics of the solar core. We review the history of the solar g-mode searches which is separated in three nearly distinct eras which correspond to: the theory of g modes, the search from the ground and the search from space. The prospects of definitive solar g-mode detection are also discussed. Title: The JOVIAL Project for Jovian Seismology Authors: Schmider, F. X.; Appourchaux, T.; Gaulme, P.; Guillot, T.; Sato, B.; Murphy, N.; Daban, J. B.; Gay, J.; Soulat, L.; Baudin, F.; Boumier, P.; Ollivier, M.; Bordé. P.; Jackiewicz, J.; Ida, S.; Showman, A. P. Bibcode: 2013ASPC..478..119S Altcode: Jovian seismology is a unique tool to determine the internal structure of the giant planet. It could uncover the size and mass of the core, if any, the existence of a “plasma phase transition” between the molecular and the metallic hydrogen envelope, reveal the internal dynamic, and more generally address the formation and evolution of giant planets in the solar system giving a point of comparison for extra solar planets. Jovian seismology requires special observing tool. SYMPA (Schmider et al. 2007; Gaulme et al. 2008) was the first project specially designed for those objectives. A new type of instrument, a Doppler Imager, had been developed. The project permitted for the first time the measurement of the fundamental acoustic frequency of Jupiter (Gaulme et al. 2011). It also validated the principle of the instrument. However, several limitations appeared during the observations. The main one was the poor temporal coverage. A new version of the Doppler Spectro Imager (DSI) has been studied extensively in the framework of the development of a space instrument for the JUICE mission. A prototype of this new device is presently developed in the laboratory (Soulat et al. 2011) and shows excellent sensitivity and stability. It will be tested on the sky in January 2014. The JOVIAL project foresees the installation of three similar instruments on three telescopes around the Earth (Japan, France, and USA) that will provide the necessary continuity in the observations. We expect to observe winds in the Jovian atmosphere with a precision better than 2 m/s and to detect modes with amplitude as low as 5 cm/s up to the degree ℓ = 10 at least. The main objective of the project is the detection of the Jovian core. Title: Asteroseismology observations and space missions Authors: Appourchaux, T.; Grundahl, F. Bibcode: 2013arXiv1312.6993A Altcode: Contribution to a book entitled "Extraterrestrial seismology". Title: Mode Line Widths in Red-Giant Stars Authors: Baudin, F.; Elsworth, Y.; Hekker, S.; Kallinger, T.; Stello, D.; Mosser, B.; Appourchaux, T.; Belkacem, K.; Benomar, O.; Barban, C.; Chaplin, W. J. Bibcode: 2013ASPC..479..179B Altcode: Mode line widths and amplitudes provide valuable information on stellar oscillation excitation and damping, and thus on physical processes such as convection, radiative losses and convection/pulsation coupling. We present preliminary results for mode line widths obtained by fitting mode spectra from Kepler observations. The difficulties of such fitting are discussed as well as these preliminary estimates in the context of models. Title: Kepler White Paper: Asteroseismology of Solar-Like Oscillators in a 2-Wheel Mission Authors: Chaplin, W. J; Kjeldsen, H.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Kawaler, S. D.; Basu, S.; De Ridder, J.; Huber, D.; Arentoft, T.; Schou, J.; Garcia, R. A.; Metcalfe, T. S.; Brogaard, K.; Campante, T. L.; Elsworth, Y.; Miglio, A.; Appourchaux, T.; Bedding, T. R.; Hekker, S.; Houdek, G.; Karoff, C.; Molenda-Zakowicz, J.; Monteiro, M. J. P. F. G.; Silva Aguirre, V.; Stello, D.; Ball, W.; Beck, P. G.; Birch, A. C.; Buzasi, D. L.; Casagrande, L.; Cellier, T.; Corsaro, E.; Creevey, O. L.; Davies, G. R.; Deheuvels, S.; Dogan, G.; Gizon, L.; Grundahl, F.; Guzik, J.; Handberg, R.; Jimenez, A.; Kallinger, T.; Lund, M. N.; Lundkvist, M.; Mathis, S.; Mathur, S.; Mazumdar, A.; Mosser, B.; Neiner, C.; Nielsen, M. B.; Palle, P. L.; Pinsonneault, M. H.; Salabert, D.; Serenelli, A. M.; Shunker, H.; White, T. R. Bibcode: 2013arXiv1309.0702C Altcode: We comment on the potential for continuing asteroseismology of solar-type and red-giant stars in a 2-wheel Kepler Mission. Our main conclusion is that by targeting stars in the ecliptic it should be possible to perform high-quality asteroseismology, as long as favorable scenarios for 2-wheel pointing performance are met. Targeting the ecliptic would potentially facilitate unique science that was not possible in the nominal Mission, notably from the study of clusters that are significantly brighter than those in the Kepler field. Our conclusions are based on predictions of 2-wheel observations made by a space photometry simulator, with information provided by the Kepler Project used as input to describe the degraded pointing scenarios. We find that elevated levels of frequency-dependent noise, consistent with the above scenarios, would have a significant negative impact on our ability to continue asteroseismic studies of solar-like oscillators in the Kepler field. However, the situation may be much more optimistic for observations in the ecliptic, provided that pointing resets of the spacecraft during regular desaturations of the two functioning reaction wheels are accurate at the < 1 arcsec level. This would make it possible to apply a post-hoc analysis that would recover most of the lost photometric precision. Without this post-hoc correction---and the accurate re-pointing it requires---the performance would probably be as poor as in the Kepler-field case. Critical to our conclusions for both fields is the assumed level of pointing noise (in the short-term jitter and the longer-term drift). We suggest that further tests will be needed to clarify our results once more detail and data on the expected pointing performance becomes available, and we offer our assistance in this work. Title: Seismic constraints on rotation of Sun-like star and mass of exoplanet Authors: Gizon, L.; Ballot, J.; Michel, E.; Stahn, T.; Vauclair, G.; Bruntt, H.; Quirion, P. -O.; Benomar, O.; Vauclair, S.; Appourchaux, T.; Auvergne, M.; Baglin, A.; Barban, C.; Baudin, F.; Bazot, M.; Campante, T.; Catala, C.; Chaplin, W.; Creevey, O.; Deheuvels, S.; Dolez, N.; Elsworth, Y.; Garcia, R.; Gaulme, P.; Mathis, S.; Mathur, S.; Mosser, B.; Regulo, C.; Roxburgh, I.; Salabert, D.; Samadi, R.; Sato, K.; Verner, G.; Hanasoge, S.; Sreenivasan, K. R. Bibcode: 2013PNAS..11013267G Altcode: 2013arXiv1308.4352G Rotation is thought to drive cyclic magnetic activity in the Sun and Sun-like stars. Stellar dynamos, however, are poorly understood owing to the scarcity of observations of rotation and magnetic fields in stars. Here, inferences are drawn on the internal rotation of a distant Sun-like star by studying its global modes of oscillation. We report asteroseismic constraints imposed on the rotation rate and the inclination of the spin axis of the Sun-like star HD 52265, a principal target observed by the CoRoT satellite that is known to host a planetary companion. These seismic inferences are remarkably consistent with an independent spectroscopic observation (rotational line broadening) and with the observed rotation period of star spots. Furthermore, asteroseismology constrains the mass of exoplanet HD 52265b. Under the standard assumption that the stellar spin axis and the axis of the planetary orbit coincide, the minimum spectroscopic mass of the planet can be converted into a true mass of 1.85 (+0.52,-0.42) M_Jupiter, which implies that it is a planet, not a brown dwarf. Title: Filtergraph Calibration for the Polarimetric and Helioseismic Imager Authors: Dominguez-Tagle, Carlos; Appourchaux, Thierry; Fourmond, Jean-Jacques; Philippon, Anne; Le Clec'h, Jean-Christophe; Bouzit, Mehdi; Le Cocguen, Regis Bibcode: 2013ists.conf...46D Altcode: ESA's Solar Orbiter mission will study the Sun to the proximity of 0.28 AU, reaching solar latitudes up to 34deg. This spacecraft will be launched in 2017 and will represent a complete approach to heliophysics. The Polarimetric and Helioseismic Imager (PHI), on board of Solar Orbiter, will provide the most important data for helioseismology. PHI will measure the photospheric vector magnetic field and the line-of-sight velocity observing the FeI 6173A absorption line with a narrowband filtergraph (FG). At different spectral positions, the polarisation state of the incoming light will be analysed. The FG will provide a tuning range to compensate the spacecraft radial velocity and to scan the continuum at both sides the absorption line. Thus, the fine tuning of the FG is essential for the instrument performance. Here we present the FG characterisation and calibration status as they represent an important milestone in the development of the instrument. Title: Helioseismology with PICARD Authors: Corbard, T.; Salabert, D.; Boumier, P.; Appourchaux, T.; Hauchecorne, A.; Journoud, P.; Nunge, A.; Gelly, B.; Hochedez, J. F.; Irbah, A.; Meftah, M.; Renaud, C.; Turck-Chièze, S. Bibcode: 2013JPhCS.440a2025C Altcode: 2013arXiv1301.6940C PICARD is a CNES micro-satellite launched in June 2010 [17]. Its main goal is to measure the solar shape, total and spectral irradiance during the ascending phase of the activity cycle. The SODISM telescope onboard PICARD also allows us to conduct a program for helioseismology in intensity at 535.7 nm [5]. One-minute cadence low-resolution full images are available for a so-called medium-l program, and high-resolution images of the limb recorded every 2 minutes are used to study mode amplification near the limb in the perspective of g-mode search. First analyses and results from these two programs are presented here. Title: Stellar Ages and Convective Cores in Field Main-sequence Stars: First Asteroseismic Application to Two Kepler Targets Authors: Silva Aguirre, V.; Basu, S.; Brandão, I. M.; Christensen-Dalsgaard, J.; Deheuvels, S.; Doğan, G.; Metcalfe, T. S.; Serenelli, A. M.; Ballot, J.; Chaplin, W. J.; Cunha, M. S.; Weiss, A.; Appourchaux, T.; Casagrande, L.; Cassisi, S.; Creevey, O. L.; García, R. A.; Lebreton, Y.; Noels, A.; Sousa, S. G.; Stello, D.; White, T. R.; Kawaler, S. D.; Kjeldsen, H. Bibcode: 2013ApJ...769..141S Altcode: 2013arXiv1304.2772S Using asteroseismic data and stellar evolution models we obtain the first detection of a convective core in a Kepler field main-sequence star, putting a stringent constraint on the total size of the mixed zone and showing that extra mixing beyond the formal convective boundary exists. In a slightly less massive target the presence of a convective core cannot be conclusively discarded, and thus its remaining main-sequence lifetime is uncertain. Our results reveal that best-fit models found solely by matching individual frequencies of oscillations corrected for surface effects do not always properly reproduce frequency combinations. Moreover, slightly different criteria to define what the best-fit model is can lead to solutions with similar global properties but very different interior structures. We argue that the use of frequency ratios is a more reliable way to obtain accurate stellar parameters, and show that our analysis in field main-sequence stars can yield an overall precision of 1.5%, 4%, and 10% in radius, mass, and age, respectively. We compare our results with those obtained from global oscillation properties, and discuss the possible sources of uncertainties in asteroseismic stellar modeling where further studies are still needed. Title: Mode lifetime and associated scaling relations Authors: Belkacem, K.; Appourchaux, T.; Baudin, F.; Dupret, M. A.; Goupil, M. J.; Marques, J. P.; Noels, A.; Samadi, R. Bibcode: 2013EPJWC..4303009B Altcode: Thanks to the CoRoT and Kepler spacecrafts, scaling relations (linking seismic indices and global stellar parameters) are becoming the cornerstone of ensemble asteroseismology. Among them, the relation between the cut-off frequency and the frequency of the maximum in the power spectrum of solar-like pulsators as well as the relation between mode lifetime and the effective temperature remain poorly understood. However, a solid theoretical background is essential to assess the accuracy of those relations and subsequently of the derived stellar parameters. We will thus present recent advances on the understanding of the underlying mechanisms governing those relations and show that the physics of mode lifetime (thus of mode damping) plays a major role. Title: VizieR Online Data Catalog: Abundances of 93 solar-type Kepler targets (Bruntt+, 2012) Authors: Bruntt, H.; Basu, S.; Smalley, B.; Chaplin, W. J.; Verner, G. A.; Bedding, T. R.; Catala, C.; Gazzano, J. -C.; Molenda-Zakowicz, J.; Thygesen, A. O.; Uytterhoeven, K.; Hekker, S.; Huber, D.; Karoff, C.; Mathur, S.; Mosser, B.; Appourchaux, T.; Campante, T. L.; Elsworth, Y.; Garcia, R. A.; Handberg, R.; Metcalfe, T. S.; Quirion, P. -O.; Regulo, C.; Roxburgh, I. W.; Stello, D.; Christensen-Dalsgaard, J.; Kawaler, S. D.; Kjeldsen, H.; Morris, R. L.; Quintana, E. V.; Sanderfer, D. T. Bibcode: 2013yCat..74230122B Altcode: The spectra were obtained with the ESPaDOnS spectrograph at the 3.6-m Canada-France-Hawaii Telescope (CFHT) in USA and with the NARVAL spectrograph mounted on the 2-m Bernard Lyot Telescope at the Pic du Midi Observatory in France. In both the facilities, the observations were carried out as service observations from May to September in 2010.

(3 data files). Title: Metrology for a solar imaging Fourier transform spectrometer working in the far UV: from the instrumental concept to the first experimental results Authors: Ruiz de Galarreta Fanjul, C.; Bouzit, M.; Appourchaux, T.; Dassas, K.; Viale, T.; Philippon, A.; Vial, J. -C.; Maillard, J. -P. Bibcode: 2012SPIE.8450E..0DR Altcode: The spectroscopy of the far UV emission lines of the solar spectrum combined with an imaging capability is essential to understand the physics of the outer solar atmosphere. An imaging Fourier transform spectrometer (IFTSUV) is an attractive instrumental solution to perform such far-UV solar observations. Working in the far UV involves high precision metrology to maintain the optical path difference (OPD) during the entire scanning process of the interferogram. It also involves a compact all-reflection design for UV applications. We present the specification of a servo-system that enables dynamic tip/tilt alignment compensation and OPD sampling measurement of the IFTSUV scanning mirror. We also discuss the first experimental results of a breadboard as well as the preliminary design of a space-based device. Title: Echoes: a new instrumental concept of spectro-imaging for Jovian seismology Authors: Soulat, L.; Schmider, F. -X.; Robbe-Dubois, S.; Appourchaux, T.; Bresson, Y.; Daban, J. -B.; Gaulme, P.; Gay, J.; Gouvret, C. Bibcode: 2012SPIE.8442E..4MS Altcode: Echoes is a project of a space-borne instrument which has been proposed as part of the JUICE mission which is selected in the Cosmic Vision program of the European Space Agency (ESA) to perform seismic and dynamics studies of Jupiter's interior and atmosphere. Based on an original Mach-Zehnder design, the instrument aims to measure Doppler shifts of solar spectral lines, which are reflected by cloud layers of Jupiter's upper troposphere, coupled with imaging capabilities. It is specified to detect global oscillations with degree up to l = 50 and amplitude as low as 1 cm/s at the surface of Jupiter. In order to check the compliance of the instrument, and its capability to operate in representative environment (TRL5), we build a prototype to perform tests. In this paper, we present the prototype implemented at Observatoire de la Côte d'Azur in collaboration with Institut d'Astrophysique Spatiale. We describe the design of the Mach-Zehnder and the procedure of control and adjustment. We present the necessary tests and we show on simulation that the measurements will provide the required precision. In conclusion, we will explain the perspective for such a new instrument. Title: Seismic Analysis of Four Solar-like Stars Observed during More Than Eight Months by Kepler Authors: Mathur, S.; Campante, T. L.; Handberg, R.; García, R. A.; Appourchaux, T.; Bedding, T. R.; Mosser, B.; Chaplin, W. J.; Ballot, J.; Benomar, O.; Bonanno, A.; Corsaro, E.; Gaulme, P.; Hekker, S.; Régulo, C.; Salabert, D.; Verner, G.; White, T. R.; Brandão, I. M.; Creevey, O. L.; Dogan, G.; Bazot, M.; Cunha, M. S.; Elsworth, Y.; Huber, D.; Hale, S. J.; Houdek, G.; Karoff, C.; Lundkvist, M.; Metcalfe, T. S.; Molenda-Zakowicz, J.; Monteiro, M. J. P. F. G.; Thompson, M. J.; Stello, D.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Kawaler, S. D.; Kjeldsen, H.; Clarke, B. D.; Girouard, F. R.; Hall, J. R.; Quintana, E. V.; Sanderfer, D. T.; Seader, S. E. Bibcode: 2012ASPC..462..180M Altcode: 2011arXiv1110.0135M Having started science operations in May 2009, the Kepler photometer has been able to provide exquisite data for solar-like stars. Five out of the 42 stars observed continuously during the survey phase show evidence of oscillations, even though they are rather faint (magnitudes from 10.5 to 12). In this paper, we present an overview of the results of the seismic analysis of 4 of these stars observed during more than eight months. Title: The EUI instrument on board the Solar Orbiter mission: from breadboard and prototypes to instrument model validation Authors: Halain, J. -P.; Rochus, P.; Renotte, E.; Appourchaux, T.; Berghmans, D.; Harra, L.; Schühle, U.; Schmutz, W.; Auchère, F.; Zhukov, A.; Dumesnil, C.; Delmotte, F.; Kennedy, T.; Mercier, R.; Pfiffner, D.; Rossi, L.; Tandy, J.; BenMoussa, A.; Smith, P. Bibcode: 2012SPIE.8443E..07H Altcode: The Solar Orbiter mission will explore the connection between the Sun and its heliosphere, taking advantage of an orbit approaching the Sun at 0.28 AU. As part of this mission, the Extreme Ultraviolet Imager (EUI) will provide full-sun and high-resolution image sequences of the solar atmosphere at selected spectral emission lines in the extreme and vacuum ultraviolet. To achieve the required scientific performances under the challenging constraints of the Solar Orbiter mission it was required to further develop existing technologies. As part of this development, and of its maturation of technology readiness, a set of breadboard and prototypes of critical subsystems have thus been realized to improve the overall instrument design. The EUI instrument architecture, its major components and sub-systems are described with their driving constraints and the expected performances based on the breadboard and prototype results. The instrument verification and qualification plan will also be discussed. We present the thermal and mechanical model validation, the instrument test campaign with the structural-thermal model (STM), followed by the other instrument models in advance of the flight instrument manufacturing and AIT campaign. Title: Seismic Evidence for a Rapidly Rotating Core in a Lower-giant-branch Star Observed with Kepler Authors: Deheuvels, S.; García, R. A.; Chaplin, W. J.; Basu, S.; Antia, H. M.; Appourchaux, T.; Benomar, O.; Davies, G. R.; Elsworth, Y.; Gizon, L.; Goupil, M. J.; Reese, D. R.; Regulo, C.; Schou, J.; Stahn, T.; Casagrande, L.; Christensen-Dalsgaard, J.; Fischer, D.; Hekker, S.; Kjeldsen, H.; Mathur, S.; Mosser, B.; Pinsonneault, M.; Valenti, J.; Christiansen, J. L.; Kinemuchi, K.; Mullally, F. Bibcode: 2012ApJ...756...19D Altcode: 2012arXiv1206.3312D Rotation is expected to have an important influence on the structure and the evolution of stars. However, the mechanisms of angular momentum transport in stars remain theoretically uncertain and very complex to take into account in stellar models. To achieve a better understanding of these processes, we desperately need observational constraints on the internal rotation of stars, which until very recently was restricted to the Sun. In this paper, we report the detection of mixed modes—i.e., modes that behave both as g modes in the core and as p modes in the envelope—in the spectrum of the early red giant KIC 7341231, which was observed during one year with the Kepler spacecraft. By performing an analysis of the oscillation spectrum of the star, we show that its non-radial modes are clearly split by stellar rotation and we are able to determine precisely the rotational splittings of 18 modes. We then find a stellar model that reproduces very well the observed atmospheric and seismic properties of the star. We use this model to perform inversions of the internal rotation profile of the star, which enables us to show that the core of the star is rotating at least five times faster than the envelope. This will shed new light on the processes of transport of angular momentum in stars. In particular, this result can be used to place constraints on the angular momentum coupling between the core and the envelope of early red giants, which could help us discriminate between the theories that have been proposed over the last few decades. Title: Oscillation mode frequencies of 61 main-sequence and subgiant stars observed by Kepler Authors: Appourchaux, T.; Chaplin, W. J.; García, R. A.; Gruberbauer, M.; Verner, G. A.; Antia, H. M.; Benomar, O.; Campante, T. L.; Davies, G. R.; Deheuvels, S.; Handberg, R.; Hekker, S.; Howe, R.; Régulo, C.; Salabert, D.; Bedding, T. R.; White, T. R.; Ballot, J.; Mathur, S.; Silva Aguirre, V.; Elsworth, Y. P.; Basu, S.; Gilliland, R. L.; Christensen-Dalsgaard, J.; Kjeldsen, H.; Uddin, K.; Stumpe, M. C.; Barclay, T. Bibcode: 2012A&A...543A..54A Altcode: 2012arXiv1204.3147A Context. Solar-like oscillations have been observed by Kepler and CoRoT in several solar-type stars, thereby providing a way to probe the stars using asteroseismology
Aims: We provide the mode frequencies of the oscillations of various stars required to perform a comparison with those obtained from stellar modelling.
Methods: We used a time series of nine months of data for each star. The 61 stars observed were categorised in three groups: simple, F-like, and mixed-mode. The simple group includes stars for which the identification of the mode degree is obvious. The F-like group includes stars for which the identification of the degree is ambiguous. The mixed-mode group includes evolved stars for which the modes do not follow the asymptotic relation of low-degree frequencies. Following this categorisation, the power spectra of the 61 main-sequence and subgiant stars were analysed using both maximum likelihood estimators and Bayesian estimators, providing individual mode characteristics such as frequencies, linewidths, and mode heights. We developed and describe a methodology for extracting a single set of mode frequencies from multiple sets derived by different methods and individual scientists. We report on how one can assess the quality of the fitted parameters using the likelihood ratio test and the posterior probabilities.
Results: We provide the mode frequencies of 61 stars (with their 1-σ error bars), as well as their associated échelle diagrams.

Appendices are available in electronic form at http://www.aanda.org Title: Accurate fundamental parameters and detailed abundance patterns from spectroscopy of 93 solar-type Kepler targets Authors: Bruntt, H.; Basu, S.; Smalley, B.; Chaplin, W. J.; Verner, G. A.; Bedding, T. R.; Catala, C.; Gazzano, J. -C.; Molenda-Żakowicz, J.; Thygesen, A. O.; Uytterhoeven, K.; Hekker, S.; Huber, D.; Karoff, C.; Mathur, S.; Mosser, B.; Appourchaux, T.; Campante, T. L.; Elsworth, Y.; García, R. A.; Handberg, R.; Metcalfe, T. S.; Quirion, P. -O.; Régulo, C.; Roxburgh, I. W.; Stello, D.; Christensen-Dalsgaard, J.; Kawaler, S. D.; Kjeldsen, H.; Morris, R. L.; Quintana, E. V.; Sanderfer, D. T. Bibcode: 2012MNRAS.423..122B Altcode: 2012arXiv1203.0611B; 2012MNRAS.tmp.3037B We present a detailed spectroscopic study of 93 solar-type stars that are targets of the NASA/Kepler mission and provide detailed chemical composition of each target. We find that the overall metallicity is well represented by Fe lines. Relative abundances of light elements (CNO) and α elements are generally higher for low-metallicity stars. Our spectroscopic analysis benefits from the accurately measured surface gravity from the asteroseismic analysis of the Kepler light curves. The accuracy on the log g parameter is better than 0.03 dex and is held fixed in the analysis. We compare our Teff determination with a recent colour calibration of VT-KS [TYCHO V magnitude minus Two Micron All Sky Survey (2MASS) KS magnitude] and find very good agreement and a scatter of only 80 K, showing that for other nearby Kepler targets, this index can be used. The asteroseismic log g values agree very well with the classical determination using Fe I-Fe II balance, although we find a small systematic offset of 0.08 dex (asteroseismic log g values are lower). The abundance patterns of metals, α elements and the light elements (CNO) show that a simple scaling by [Fe/H] is adequate to represent the metallicity of the stars, except for the stars with metallicity below -0.3, where α-enhancement becomes important. However, this is only important for a very small fraction of the Kepler sample. We therefore recommend that a simple scaling with [Fe/H] be employed in the asteroseismic analyses of large ensembles of solar-type stars. Title: Solving the Mode Identification Problem in Asteroseismology of F Stars Observed with Kepler Authors: White, Timothy R.; Bedding, Timothy R.; Gruberbauer, Michael; Benomar, Othman; Stello, Dennis; Appourchaux, Thierry; Chaplin, William J.; Christensen-Dalsgaard, Jørgen; Elsworth, Yvonne P.; García, Rafael A.; Hekker, Saskia; Huber, Daniel; Kjeldsen, Hans; Mosser, Benoît; Kinemuchi, Karen; Mullally, Fergal; Still, Martin Bibcode: 2012ApJ...751L..36W Altcode: 2012arXiv1205.0544W Asteroseismology of F-type stars has been hindered by an ambiguity in identification of their oscillation modes. The regular mode pattern that makes this task trivial in cooler stars is masked by increased line widths. The absolute mode frequencies, encapsulated in the asteroseismic variable epsilon, can help solve this impasse because the values of epsilon implied by the two possible mode identifications are distinct. We find that the correct epsilon can be deduced from the effective temperature and the line widths and we apply these methods to a sample of solar-like oscillators observed with Kepler. Title: Damping rates of solar-like oscillations across the HR diagram. Theoretical calculations confronted to CoRoT and Kepler observations Authors: Belkacem, K.; Dupret, M. A.; Baudin, F.; Appourchaux, T.; Marques, J. P.; Samadi, R. Bibcode: 2012A&A...540L...7B Altcode: 2012arXiv1203.1737B The space-borne missions CoRoT and Kepler are providing a rich harvest of high-quality constraints on solar-like pulsators. Among the seismic parameters, mode damping rates remains poorly understood and are thus barely used to infer the physical properties of stars. Nevertheless, thanks to the CoRoT and Kepler spacecrafts it is now possible to measure damping rates for hundreds of main-sequence and thousands of red-giant stars with unprecedented precision. By using a non-adiabatic pulsation code including a time-dependent convection treatment, we compute damping rates for stellar models that are representative of solar-like pulsators from the main-sequence to the red-giant phase. This allows us to reproduce the observations of both CoRoT and Kepler, which validates our modeling of mode damping rates and thus the underlying physical mechanisms included in the modeling. By considering the perturbations of turbulent pressure and entropy (including the perturbation of the dissipation rate of turbulent energy into heat) by the oscillation in our computation, we succeed in reproducing the observed relation between damping rates and effective temperature. Moreover, we discuss the physical reasons for mode damping rates to scale with effective temperature, as observationally exhibited. Finally, this opens the way for the use of mode damping rates to probe turbulent convection in solar-like stars. Title: A Uniform Asteroseismic Analysis of 22 Solar-type Stars Observed by Kepler Authors: Mathur, S.; Metcalfe, T. S.; Woitaszek, M.; Bruntt, H.; Verner, G. A.; Christensen-Dalsgaard, J.; Creevey, O. L.; Doǧan, G.; Basu, S.; Karoff, C.; Stello, D.; Appourchaux, T.; Campante, T. L.; Chaplin, W. J.; García, R. A.; Bedding, T. R.; Benomar, O.; Bonanno, A.; Deheuvels, S.; Elsworth, Y.; Gaulme, P.; Guzik, J. A.; Handberg, R.; Hekker, S.; Herzberg, W.; Monteiro, M. J. P. F. G.; Piau, L.; Quirion, P. -O.; Régulo, C.; Roth, M.; Salabert, D.; Serenelli, A.; Thompson, M. J.; Trampedach, R.; White, T. R.; Ballot, J.; Brandão, I. M.; Molenda-Żakowicz, J.; Kjeldsen, H.; Twicken, J. D.; Uddin, K.; Wohler, B. Bibcode: 2012ApJ...749..152M Altcode: 2012arXiv1202.2844M Asteroseismology with the Kepler space telescope is providing not only an improved characterization of exoplanets and their host stars, but also a new window on stellar structure and evolution for the large sample of solar-type stars in the field. We perform a uniform analysis of 22 of the brightest asteroseismic targets with the highest signal-to-noise ratio observed for 1 month each during the first year of the mission, and we quantify the precision and relative accuracy of asteroseismic determinations of the stellar radius, mass, and age that are possible using various methods. We present the properties of each star in the sample derived from an automated analysis of the individual oscillation frequencies and other observational constraints using the Asteroseismic Modeling Portal (AMP), and we compare them to the results of model-grid-based methods that fit the global oscillation properties. We find that fitting the individual frequencies typically yields asteroseismic radii and masses to ~1% precision, and ages to ~2.5% precision (respectively, 2, 5, and 8 times better than fitting the global oscillation properties). The absolute level of agreement between the results from different approaches is also encouraging, with model-grid-based methods yielding slightly smaller estimates of the radius and mass and slightly older values for the stellar age relative to AMP, which computes a large number of dedicated models for each star. The sample of targets for which this type of analysis is possible will grow as longer data sets are obtained during the remainder of the mission. Title: Asteroseismology of the Solar Analogs 16 Cyg A and B from Kepler Observations Authors: Metcalfe, T. S.; Chaplin, W. J.; Appourchaux, T.; García, R. A.; Basu, S.; Brandão, I.; Creevey, O. L.; Deheuvels, S.; Doǧan, G.; Eggenberger, P.; Karoff, C.; Miglio, A.; Stello, D.; Yıldız, M.; Çelik, Z.; Antia, H. M.; Benomar, O.; Howe, R.; Régulo, C.; Salabert, D.; Stahn, T.; Bedding, T. R.; Davies, G. R.; Elsworth, Y.; Gizon, L.; Hekker, S.; Mathur, S.; Mosser, B.; Bryson, S. T.; Still, M. D.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Kawaler, S. D.; Kjeldsen, H.; Ibrahim, K. A.; Klaus, T. C.; Li, J. Bibcode: 2012ApJ...748L..10M Altcode: 2012arXiv1201.5966M The evolved solar-type stars 16 Cyg A and B have long been studied as solar analogs, yielding a glimpse into the future of our own Sun. The orbital period of the binary system is too long to provide meaningful dynamical constraints on the stellar properties, but asteroseismology can help because the stars are among the brightest in the Kepler field. We present an analysis of three months of nearly uninterrupted photometry of 16 Cyg A and B from the Kepler space telescope. We extract a total of 46 and 41 oscillation frequencies for the two components, respectively, including a clear detection of octupole (l = 3) modes in both stars. We derive the properties of each star independently using the Asteroseismic Modeling Portal, fitting the individual oscillation frequencies and other observational constraints simultaneously. We evaluate the systematic uncertainties from an ensemble of results generated by a variety of stellar evolution codes and fitting methods. The optimal models derived by fitting each component individually yield a common age (t = 6.8 ± 0.4 Gyr) and initial composition (Z i = 0.024 ± 0.002, Y i = 0.25 ± 0.01) within the uncertainties, as expected for the components of a binary system, bolstering our confidence in the reliability of asteroseismic techniques. The longer data sets that will ultimately become available will allow future studies of differential rotation, convection zone depths, and long-term changes due to stellar activity cycles. Title: Acoustic spectrum fitting for a large set of solar-like pulsators Authors: Benomar, O.; Baudin, F.; Chaplin, W. J.; Elsworth, Y.; Appourchaux, T. Bibcode: 2012MNRAS.420.2178B Altcode: 2011MNRAS.tmp.2149B Asteroseismology provides the means both to constrain the global properties and to probe the internal structures of stars. Asteroseismic data are now available on large numbers of solar-type stars, thanks in particular to the CoRoT and Kepler space missions, and automated data-analysis pipelines are needed to provide efficient and timely results. Here, we present an automated algorithm that is able to extract mode parameters under low signal-to-noise ratio conditions. We use a Bayesian framework to ensure the robustness of the algorithm. We discuss the efficiency of the method and test it using Variability of Solar Irradiance and Gravity Oscillations (VIRGO) Sun-as-a-star photometry data and the artificial Astero Fitting at Low Angular degree Group (asteroFLAG) Kepler ensemble. Analysis of the VIRGO data shows that it is possible to track variations of the individual mode parameters (frequency, height, width) through the solar cycle, using short time series (30 days). The present analysis also revealed a modulation of the degree l = 2 relative height through the solar cycle. Applied on asteroFLAG data, we show that the pipeline extracts accurately the central frequency and the large separation. It is also able to identify the degree of the modes in 78 per cent of stars. Title: Kepler-21b: A 1.6 R Earth Planet Transiting the Bright Oscillating F Subgiant Star HD 179070 Authors: Howell, Steve B.; Rowe, Jason F.; Bryson, Stephen T.; Quinn, Samuel N.; Marcy, Geoffrey W.; Isaacson, Howard; Ciardi, David R.; Chaplin, William J.; Metcalfe, Travis S.; Monteiro, Mario J. P. F. G.; Appourchaux, Thierry; Basu, Sarbani; Creevey, Orlagh L.; Gilliland, Ronald L.; Quirion, Pierre-Olivier; Stello, Denis; Kjeldsen, Hans; Christensen-Dalsgaard, Jörgen; Elsworth, Yvonne; García, Rafael A.; Houdek, Günter; Karoff, Christoffer; Molenda-Żakowicz, Joanna; Thompson, Michael J.; Verner, Graham A.; Torres, Guillermo; Fressin, Francois; Crepp, Justin R.; Adams, Elisabeth; Dupree, Andrea; Sasselov, Dimitar D.; Dressing, Courtney D.; Borucki, William J.; Koch, David G.; Lissauer, Jack J.; Latham, David W.; Buchhave, Lars A.; Gautier, Thomas N., III; Everett, Mark; Horch, Elliott; Batalha, Natalie M.; Dunham, Edward W.; Szkody, Paula; Silva, David R.; Mighell, Ken; Holberg, Jay; Ballot, Jerôme; Bedding, Timothy R.; Bruntt, Hans; Campante, Tiago L.; Handberg, Rasmus; Hekker, Saskia; Huber, Daniel; Mathur, Savita; Mosser, Benoit; Régulo, Clara; White, Timothy R.; Christiansen, Jessie L.; Middour, Christopher K.; Haas, Michael R.; Hall, Jennifer R.; Jenkins, Jon M.; McCaulif, Sean; Fanelli, Michael N.; Kulesa, Craig; McCarthy, Don; Henze, Christopher E. Bibcode: 2012ApJ...746..123H Altcode: 2011arXiv1112.2165H We present Kepler observations of the bright (V = 8.3), oscillating star HD 179070. The observations show transit-like events which reveal that the star is orbited every 2.8 days by a small, 1.6 R Earth object. Seismic studies of HD 179070 using short cadence Kepler observations show that HD 179070 has a frequency-power spectrum consistent with solar-like oscillations that are acoustic p-modes. Asteroseismic analysis provides robust values for the mass and radius of HD 179070, 1.34 ± 0.06 M ⊙ and 1.86 ± 0.04 R ⊙, respectively, as well as yielding an age of 2.84 ± 0.34 Gyr for this F5 subgiant. Together with ground-based follow-up observations, analysis of the Kepler light curves and image data, and blend scenario models, we conservatively show at the >99.7% confidence level (3σ) that the transit event is caused by a 1.64 ± 0.04 R Earth exoplanet in a 2.785755 ± 0.000032 day orbit. The exoplanet is only 0.04 AU away from the star and our spectroscopic observations provide an upper limit to its mass of ~10 M Earth (2σ). HD 179070 is the brightest exoplanet host star yet discovered by Kepler.

Based in part on observations obtained at the W. M. Keck Observatory, which is operated by the University of California and the California Institute of Technology, the Mayall telescope at Kitt Peak National Observatory, and the WIYN Observatory which is a joint facility of NOAO, University of Wisconsin-Madison, Indiana University, and Yale University. Title: Oscillation mode linewidths of main-sequence and subgiant stars observed by Kepler Authors: Appourchaux, T.; Benomar, O.; Gruberbauer, M.; Chaplin, W. J.; García, R. A.; Handberg, R.; Verner, G. A.; Antia, H. M.; Campante, T. L.; Davies, G. R.; Deheuvels, S.; Hekker, S.; Howe, R.; Salabert, D.; Bedding, T. R.; White, T. R.; Houdek, G.; Silva Aguirre, V.; Elsworth, Y. P.; van Cleve, J.; Clarke, B. D.; Hall, J. R.; Kjeldsen, H. Bibcode: 2012A&A...537A.134A Altcode: 2011arXiv1112.3295A Context. Solar-like oscillations have been observed by Kepler and CoRoT in several solar-type stars.
Aims: We study the variations in the stellar p-mode linewidth as a function of effective temperature.
Methods: We study a time series of nine months of Kepler data. We analyse the power spectra of 42 cool main-sequence stars and subgiants using both maximum likelihood estimators and Bayesian estimators to recover individual mode characteristics such as frequencies, linewidths, and mode heights.
Results: We report on the mode linewidth at both maximum power and maximum mode height for these 42 stars as a function of effective temperature.
Conclusions: We show that the mode linewidth at either maximum mode height or maximum amplitude follows a scaling relation with effective temperature, which is a combination of a power law and a lower bound. The typical power-law index is about 13 for the linewidth derived from the maximum mode height, and about 16 for the linewidth derived from the maximum amplitude, while the lower bound is about 0.3 μHz and 0.7 μHz, respectively. We stress that this scaling relation is only valid for cool main-sequence stars and subgiants, and does not have any predictive power outside the temperature range of these stars. Title: Testing Scaling Relations for Solar-like Oscillations from the Main Sequence to Red Giants Using Kepler Data Authors: Huber, D.; Bedding, T. R.; Stello, D.; Hekker, S.; Mathur, S.; Mosser, B.; Verner, G. A.; Bonanno, A.; Buzasi, D. L.; Campante, T. L.; Elsworth, Y. P.; Hale, S. J.; Kallinger, T.; Silva Aguirre, V.; Chaplin, W. J.; De Ridder, J.; García, R. A.; Appourchaux, T.; Frandsen, S.; Houdek, G.; Molenda-Żakowicz, J.; Monteiro, M. J. P. F. G.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Kawaler, S. D.; Kjeldsen, H.; Broomhall, A. M.; Corsaro, E.; Salabert, D.; Sanderfer, D. T.; Seader, S. E.; Smith, J. C. Bibcode: 2011ApJ...743..143H Altcode: 2011arXiv1109.3460H We have analyzed solar-like oscillations in ~1700 stars observed by the Kepler Mission, spanning from the main sequence to the red clump. Using evolutionary models, we test asteroseismic scaling relations for the frequency of maximum power (νmax), the large frequency separation (Δν), and oscillation amplitudes. We show that the difference of the Δν-νmax relation for unevolved and evolved stars can be explained by different distributions in effective temperature and stellar mass, in agreement with what is expected from scaling relations. For oscillation amplitudes, we show that neither (L/M) s scaling nor the revised scaling relation by Kjeldsen & Bedding is accurate for red-giant stars, and demonstrate that a revised scaling relation with a separate luminosity-mass dependence can be used to calculate amplitudes from the main sequence to red giants to a precision of ~25%. The residuals show an offset particularly for unevolved stars, suggesting that an additional physical dependency is necessary to fully reproduce the observed amplitudes. We investigate correlations between amplitudes and stellar activity, and find evidence that the effect of amplitude suppression is most pronounced for subgiant stars. Finally, we test the location of the cool edge of the instability strip in the Hertzsprung-Russell diagram using solar-like oscillations and find the detections in the hottest stars compatible with a domain of hybrid stochastically excited and opacity driven pulsation. Title: Asteroseismic Diagrams from a Survey of Solar-like Oscillations with Kepler Authors: White, Timothy R.; Bedding, Timothy R.; Stello, Dennis; Appourchaux, Thierry; Ballot, Jérôme; Benomar, Othman; Bonanno, Alfio; Broomhall, Anne-Marie; Campante, Tiago L.; Chaplin, William J.; Christensen-Dalsgaard, Jørgen; Corsaro, Enrico; Doǧan, Gülnur; Elsworth, Yvonne P.; Fletcher, Stephen T.; García, Rafael A.; Gaulme, Patrick; Handberg, Rasmus; Hekker, Saskia; Huber, Daniel; Karoff, Christoffer; Kjeldsen, Hans; Mathur, Savita; Mosser, Benoit; Monteiro, Mario J. P. F. G.; Régulo, Clara; Salabert, David; Silva Aguirre, Victor; Thompson, Michael J.; Verner, Graham; Morris, Robert L.; Sanderfer, Dwight T.; Seader, Shawn E. Bibcode: 2011ApJ...742L...3W Altcode: 2011arXiv1110.1375W Photometric observations made by the NASA Kepler Mission have led to a dramatic increase in the number of main-sequence and subgiant stars with detected solar-like oscillations. We present an ensemble asteroseismic analysis of 76 solar-type stars. Using frequencies determined from the Kepler time-series photometry, we have measured three asteroseismic parameters that characterize the oscillations: the large frequency separation (Δν), the small frequency separation between modes of l = 0 and l = 2 (δν02), and the dimensionless offset (epsilon). These measurements allow us to construct asteroseismic diagrams, namely the so-called Christensen-Dalsgaard diagram of δν02 versus Δν, and the recently re-introduced epsilon diagram. We compare the Kepler results with previously observed solar-type stars and with theoretical models. The positions of stars in these diagrams places constraints on their masses and ages. Additionally, we confirm the observational relationship between epsilon and T eff that allows for the unambiguous determination of radial order and should help resolve the problem of mode identification in F stars. Title: Constructing a One-solar-mass Evolutionary Sequence Using Asteroseismic Data from Kepler Authors: Silva Aguirre, V.; Chaplin, W. J.; Ballot, J.; Basu, S.; Bedding, T. R.; Serenelli, A. M.; Verner, G. A.; Miglio, A.; Monteiro, M. J. P. F. G.; Weiss, A.; Appourchaux, T.; Bonanno, A.; Broomhall, A. M.; Bruntt, H.; Campante, T. L.; Casagrande, L.; Corsaro, E.; Elsworth, Y.; García, R. A.; Gaulme, P.; Handberg, R.; Hekker, S.; Huber, D.; Karoff, C.; Mathur, S.; Mosser, B.; Salabert, D.; Schönrich, R.; Sousa, S. G.; Stello, D.; White, T. R.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Kawaler, S. D.; Kjeldsen, H.; Houdek, G.; Metcalfe, T. S.; Molenda-Żakowicz, J.; Thompson, M. J.; Caldwell, D. A.; Christiansen, J. L.; Wohler, B. Bibcode: 2011ApJ...740L...2S Altcode: 2011arXiv1108.2031S Asteroseismology of solar-type stars has entered a new era of large surveys with the success of the NASA Kepler mission, which is providing exquisite data on oscillations of stars across the Hertzsprung-Russell diagram. From the time-series photometry, the two seismic parameters that can be most readily extracted are the large frequency separation (Δν) and the frequency of maximum oscillation power (νmax). After the survey phase, these quantities are available for hundreds of solar-type stars. By scaling from solar values, we use these two asteroseismic observables to identify for the first time an evolutionary sequence of 1 M sun field stars, without the need for further information from stellar models. Comparison of our determinations with the few available spectroscopic results shows an excellent level of agreement. We discuss the potential of the method for differential analysis throughout the main-sequence evolution and the possibility of detecting twins of very well-known stars. Title: Asteroseismology from multi-month Kepler photometry: the evolved Sun-like stars KIC 10273246 and KIC 10920273 Authors: Campante, T. L.; Handberg, R.; Mathur, S.; Appourchaux, T.; Bedding, T. R.; Chaplin, W. J.; García, R. A.; Mosser, B.; Benomar, O.; Bonanno, A.; Corsaro, E.; Fletcher, S. T.; Gaulme, P.; Hekker, S.; Karoff, C.; Régulo, C.; Salabert, D.; Verner, G. A.; White, T. R.; Houdek, G.; Brandão, I. M.; Creevey, O. L.; Doǧan, G.; Bazot, M.; Christensen-Dalsgaard, J.; Cunha, M. S.; Elsworth, Y.; Huber, D.; Kjeldsen, H.; Lundkvist, M.; Molenda-Żakowicz, J.; Monteiro, M. J. P. F. G.; Stello, D.; Clarke, B. D.; Girouard, F. R.; Hall, J. R. Bibcode: 2011A&A...534A...6C Altcode: 2011arXiv1108.3807C Context. The evolved main-sequence Sun-like stars KIC 10273246 (F-type) and KIC 10920273 (G-type) were observed with the NASA Kepler satellite for approximately ten months with a duty cycle in excess of 90%. Such continuous and long observations are unprecedented for solar-type stars other than the Sun.
Aims: We aimed mainly at extracting estimates of p-mode frequencies - as well as of other individual mode parameters - from the power spectra of the light curves of both stars, thus providing scope for a full seismic characterization.
Methods: The light curves were corrected for instrumental effects in a manner independent of the Kepler science pipeline. Estimation of individual mode parameters was based both on the maximization of the likelihood of a model describing the power spectrum and on a classic prewhitening method. Finally, we employed a procedure for selecting frequency lists to be used in stellar modeling.
Results: A total of 30 and 21 modes of degree l = 0,1,2 - spanning at least eight radial orders - have been identified for KIC 10273246 and KIC 10920273, respectively. Two avoided crossings (l = 1 ridge) have been identified for KIC 10273246, whereas one avoided crossing plus another likely one have been identified for KIC 10920273. Good agreement is found between observed and predicted mode amplitudes for the F-type star KIC 10273246, based on a revised scaling relation. Estimates are given of the rotational periods, the parameters describing stellar granulation and the global asteroseismic parameters Δν and νmax. Title: Verification of the Kepler Input Catalog from Asteroseismology of Solar-type Stars Authors: Verner, G. A.; Chaplin, W. J.; Basu, S.; Brown, T. M.; Hekker, S.; Huber, D.; Karoff, C.; Mathur, S.; Metcalfe, T. S.; Mosser, B.; Quirion, P. -O.; Appourchaux, T.; Bedding, T. R.; Bruntt, H.; Campante, T. L.; Elsworth, Y.; García, R. A.; Handberg, R.; Régulo, C.; Roxburgh, I. W.; Stello, D.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Kawaler, S. D.; Kjeldsen, H.; Allen, C.; Clarke, B. D.; Girouard, F. R. Bibcode: 2011ApJ...738L..28V Altcode: 2011arXiv1109.0869V We calculate precise stellar radii and surface gravities from the asteroseismic analysis of over 500 solar-type pulsating stars observed by the Kepler space telescope. These physical stellar properties are compared with those given in the Kepler Input Catalog (KIC), determined from ground-based multi-color photometry. For the stars in our sample, we find general agreement but we detect an average overestimation bias of 0.23 dex in the KIC determination of log (g) for stars with log (g)KIC > 4.0 dex, and a resultant underestimation bias of up to 50% in the KIC radii estimates for stars with R KIC < 2 R sun. Part of the difference may arise from selection bias in the asteroseismic sample; nevertheless, this result implies there may be fewer stars characterized in the KIC with R ~ 1 R sun than is suggested by the physical properties in the KIC. Furthermore, if the radius estimates are taken from the KIC for these affected stars and then used to calculate the size of transiting planets, a similar underestimation bias may be applied to the planetary radii. Title: Global asteroseismic properties of solar-like oscillations observed by Kepler: a comparison of complementary analysis methods Authors: Verner, G. A.; Elsworth, Y.; Chaplin, W. J.; Campante, T. L.; Corsaro, E.; Gaulme, P.; Hekker, S.; Huber, D.; Karoff, C.; Mathur, S.; Mosser, B.; Appourchaux, T.; Ballot, J.; Bedding, T. R.; Bonanno, A.; Broomhall, A. -M.; García, R. A.; Handberg, R.; New, R.; Stello, D.; Régulo, C.; Roxburgh, I. W.; Salabert, D.; White, T. R.; Caldwell, D. A.; Christiansen, J. L.; Fanelli, M. N. Bibcode: 2011MNRAS.415.3539V Altcode: 2011MNRAS.tmp..892V; 2011arXiv1105.0571V We present the asteroseismic analysis of 1948 F-, G- and K-type main-sequence and subgiant stars observed by the National Aeronautics and Space Administration Kepler mission. We detect and characterize solar-like oscillations in 642 of these stars. This represents the largest cohort of main-sequence and subgiant solar-like oscillators observed to date. The photometric observations are analysed using the methods developed by nine independent research teams. The results are combined to validate the determined global asteroseismic parameters and calculate the relative precision by which the parameters can be obtained. We correlate the relative number of detected solar-like oscillators with stellar parameters from the Kepler Input Catalogue and find a deficiency for stars with effective temperatures in the range 5300 ≲Teff≲ 5700 K and a drop-off in detected oscillations in stars approaching the red edge of the classical instability strip. We compare the power-law relationships between the frequency of peak power, νmax, the mean large frequency separation, Δν, and the maximum mode amplitude, Amax, and show that there are significant method-dependent differences in the results obtained. This illustrates the need for multiple complementary analysis methods to be used to assess the robustness and reproducibility of results derived from global asteroseismic parameters. Title: Solar-like Oscillations in KIC 11395018 and KIC 11234888 from 8 Months of Kepler Data Authors: Mathur, S.; Handberg, R.; Campante, T. L.; García, R. A.; Appourchaux, T.; Bedding, T. R.; Mosser, B.; Chaplin, W. J.; Ballot, J.; Benomar, O.; Bonanno, A.; Corsaro, E.; Gaulme, P.; Hekker, S.; Régulo, C.; Salabert, D.; Verner, G.; White, T. R.; Brandão, I. M.; Creevey, O. L.; Doǧan, G.; Elsworth, Y.; Huber, D.; Hale, S. J.; Houdek, G.; Karoff, C.; Metcalfe, T. S.; Molenda-Żakowicz, J.; Monteiro, M. J. P. F. G.; Thompson, M. J.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Kawaler, S. D.; Kjeldsen, H.; Quintana, E. V.; Sanderfer, D. T.; Seader, S. E. Bibcode: 2011ApJ...733...95M Altcode: 2011arXiv1103.4085M We analyze the photometric short-cadence data obtained with the Kepler mission during the first 8 months of observations of two solar-type stars of spectral types G and F: KIC 11395018 and KIC 11234888, respectively, the latter having a lower signal-to-noise ratio (S/N) compared with the former. We estimate global parameters of the acoustic (p) modes such as the average large and small frequency separations, the frequency of the maximum of the p-mode envelope, and the average line width of the acoustic modes. We were able to identify and to measure 22 p-mode frequencies for the first star and 16 for the second one even though the S/N of these stars are rather low. We also derive some information about the stellar rotation periods from the analyses of the low-frequency parts of the power spectral densities. A model-independent estimation of the mean density, mass, and radius is obtained using the scaling laws. We emphasize the importance of continued observations for the stars with low S/N for an improved characterization of the oscillation modes. Our results offer a preview of what will be possible for many stars with the long data sets obtained during the remainder of the mission. Title: Preparation of Kepler light curves for asteroseismic analyses Authors: García, R. A.; Hekker, S.; Stello, D.; Gutiérrez-Soto, J.; Handberg, R.; Huber, D.; Karoff, C.; Uytterhoeven, K.; Appourchaux, T.; Chaplin, W. J.; Elsworth, Y.; Mathur, S.; Ballot, J.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Houdek, G.; Jenkins, J. M.; Kjeldsen, H.; McCauliff, S.; Metcalfe, T.; Middour, C. K.; Molenda-Zakowicz, J.; Monteiro, M. J. P. F. G.; Smith, J. C.; Thompson, M. J. Bibcode: 2011MNRAS.414L...6G Altcode: 2011arXiv1103.0382G The Kepler mission is providing photometric data of exquisite quality for the asteroseismic study of different classes of pulsating stars. These analyses place particular demands on the pre-processing of the data, over a range of time-scales from minutes to months. Here, we describe processing procedures developed by the Kepler Asteroseismic Science Consortium to prepare light curves that are optimized for the asteroseismic study of solar-like oscillating stars in which outliers, jumps and drifts are corrected. Title: Accurate p-mode measurements of the G0V metal-rich CoRoT target HD 52265 Authors: Ballot, J.; Gizon, L.; Samadi, R.; Vauclair, G.; Benomar, O.; Bruntt, H.; Mosser, B.; Stahn, T.; Verner, G. A.; Campante, T. L.; García, R. A.; Mathur, S.; Salabert, D.; Gaulme, P.; Régulo, C.; Roxburgh, I. W.; Appourchaux, T.; Baudin, F.; Catala, C.; Chaplin, W. J.; Deheuvels, S.; Michel, E.; Bazot, M.; Creevey, O.; Dolez, N.; Elsworth, Y.; Sato, K. H.; Vauclair, S.; Auvergne, M.; Baglin, A. Bibcode: 2011A&A...530A..97B Altcode: 2011arXiv1105.3551B Context. The star HD 52265 is a G0V metal-rich exoplanet-host star observed in the seismology field of the CoRoT space telescope from November 2008 to March 2009. The satellite collected 117 days of high-precision photometric data on this star, showing that it presents solar-like oscillations. HD 52265 was also observed in spectroscopy with the Narval spectrograph at the same epoch.
Aims: We characterise HD 52265 using both spectroscopic and seismic data.
Methods: The fundamental stellar parameters of HD 52265 were derived with the semi-automatic software VWA, and the projected rotational velocity was estimated by fitting synthetic profiles to isolated lines in the observed spectrum. The parameters of the observed p modes were determined with a maximum-likelihood estimation. We performed a global fit of the oscillation spectrum, over about ten radial orders, for degrees l = 0 to 2. We also derived the properties of the granulation, and analysed a signature of the rotation induced by the photospheric magnetic activity.
Results: Precise determinations of fundamental parameters have been obtained: Teff = 6100 ± 60 K, log g = 4.35 ± 0.09, [M/H] = 0.19 ± 0.05, as well as vsini=3.6+0.3-1.0kms. We have measured a mean rotation period Prot = 12.3 ± 0.15 days, and find a signature of differential rotation. The frequencies of 31 modes are reported in the range 1500-2550 μHz. The large separation exhibits a clear modulation around the mean value Dnu=98.3 ± 0.1 μHz. Mode widths vary with frequency along an S-shape with a clear local maximum around 1800 μHz. We deduce lifetimes ranging between 0.5 and 3 days for these modes. Finally, we find a maximal bolometric amplitude of about 3.96 ± 0.24 ppm for radial modes.

The CoRoT space mission, launched on December 27th 2006, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA (RSSD and Science Programme), Germany and Spain. Title: Predicting the Detectability of Oscillations in Solar-type Stars Observed by Kepler Authors: Chaplin, W. J.; Kjeldsen, H.; Bedding, T. R.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Kawaler, S. D.; Appourchaux, T.; Elsworth, Y.; García, R. A.; Houdek, G.; Karoff, C.; Metcalfe, T. S.; Molenda-Żakowicz, J.; Monteiro, M. J. P. F. G.; Thompson, M. J.; Verner, G. A.; Batalha, N.; Borucki, W. J.; Brown, T. M.; Bryson, S. T.; Christiansen, J. L.; Clarke, B. D.; Jenkins, J. M.; Klaus, T. C.; Koch, D.; An, D.; Ballot, J.; Basu, S.; Benomar, O.; Bonanno, A.; Broomhall, A. -M.; Campante, T. L.; Corsaro, E.; Creevey, O. L.; Esch, L.; Gai, N.; Gaulme, P.; Hale, S. J.; Handberg, R.; Hekker, S.; Huber, D.; Mathur, S.; Mosser, B.; New, R.; Pinsonneault, M. H.; Pricopi, D.; Quirion, P. -O.; Régulo, C.; Roxburgh, I. W.; Salabert, D.; Stello, D.; Suran, M. D. Bibcode: 2011ApJ...732...54C Altcode: 2011arXiv1103.0702C Asteroseismology of solar-type stars has an important part to play in the exoplanet program of the NASA Kepler Mission. Precise and accurate inferences on the stellar properties that are made possible by the seismic data allow very tight constraints to be placed on the exoplanetary systems. Here, we outline how to make an estimate of the detectability of solar-like oscillations in any given Kepler target, using rough estimates of the temperature and radius, and the Kepler apparent magnitude. Title: Evidence for the Impact of Stellar Activity on the Detectability of Solar-like Oscillations Observed by Kepler Authors: Chaplin, W. J.; Bedding, T. R.; Bonanno, A.; Broomhall, A. -M.; García, R. A.; Hekker, S.; Huber, D.; Verner, G. A.; Basu, S.; Elsworth, Y.; Houdek, G.; Mathur, S.; Mosser, B.; New, R.; Stevens, I. R.; Appourchaux, T.; Karoff, C.; Metcalfe, T. S.; Molenda-Żakowicz, J.; Monteiro, M. J. P. F. G.; Thompson, M. J.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Kawaler, S. D.; Kjeldsen, H.; Ballot, J.; Benomar, O.; Corsaro, E.; Campante, T. L.; Gaulme, P.; Hale, S. J.; Handberg, R.; Jarvis, E.; Régulo, C.; Roxburgh, I. W.; Salabert, D.; Stello, D.; Mullally, F.; Li, J.; Wohler, W. Bibcode: 2011ApJ...732L...5C Altcode: 2011arXiv1103.5570C We use photometric observations of solar-type stars, made by the NASA Kepler Mission, to conduct a statistical study of the impact of stellar surface activity on the detectability of solar-like oscillations. We find that the number of stars with detected oscillations falls significantly with increasing levels of activity. The results present strong evidence for the impact of magnetic activity on the properties of near-surface convection in the stars, which appears to inhibit the amplitudes of the stochastically excited, intrinsically damped solar-like oscillations. Title: Ensemble Asteroseismology of Solar-Type Stars with the NASA Kepler Mission Authors: Chaplin, W. J.; Kjeldsen, H.; Christensen-Dalsgaard, J.; Basu, S.; Miglio, A.; Appourchaux, T.; Bedding, T. R.; Elsworth, Y.; García, R. A.; Gilliland, R. L.; Girardi, L.; Houdek, G.; Karoff, C.; Kawaler, S. D.; Metcalfe, T. S.; Molenda-Żakowicz, J.; Monteiro, M. J. P. F. G.; Thompson, M. J.; Verner, G. A.; Ballot, J.; Bonanno, A.; Brandão, I. M.; Broomhall, A. -M.; Bruntt, H.; Campante, T. L.; Corsaro, E.; Creevey, O. L.; Doğan, G.; Esch, L.; Gai, N.; Gaulme, P.; Hale, S. J.; Handberg, R.; Hekker, S.; Huber, D.; Jiménez, A.; Mathur, S.; Mazumdar, A.; Mosser, B.; New, R.; Pinsonneault, M. H.; Pricopi, D.; Quirion, P. -O.; Régulo, C.; Salabert, D.; Serenelli, A. M.; Silva Aguirre, V.; Sousa, S. G.; Stello, D.; Stevens, I. R.; Suran, M. D.; Uytterhoeven, K.; White, T. R.; Borucki, W. J.; Brown, T. M.; Jenkins, J. M.; Kinemuchi, K.; Van Cleve, J.; Klaus, T. C. Bibcode: 2011Sci...332..213C Altcode: 2011arXiv1109.4723C In addition to its search for extrasolar planets, the NASA Kepler mission provides exquisite data on stellar oscillations. We report the detections of oscillations in 500 solar-type stars in the Kepler field of view, an ensemble that is large enough to allow statistical studies of intrinsic stellar properties (such as mass, radius, and age) and to test theories of stellar evolution. We find that the distribution of observed masses of these stars shows intriguing differences to predictions from models of synthetic stellar populations in the Galaxy. Title: The Solar Orbiter Mission and its Polarimetric and Helioseismic Imager (SO/PHI) Authors: Gandorfer, Achim; Solanki, Sami K.; Woch, Joachim; Martínez Pillet, Valentin; Álvarez Herrero, Alberto; Appourchaux, Thierry Bibcode: 2011JPhCS.271a2086G Altcode: We briefly outline the scientific and instrumental aspects of ESA's Solar Orbiter mission. Special emphasis is given to the Polarimetric and Helioseismic Imager, the instrument with the highest relevance for helioseismology applications, which will observe gas motions and the vector magnetic field in the photosphere at high spatial and temporal resolution. Title: PLATO : PLAnetary Transits and Oscillations of stars Authors: Catala, Claude; Appourchaux, Thierry; Plato Mission Consortium Bibcode: 2011JPhCS.271a2084C Altcode: PLATO is a M-class candidate in the ESA Cosmic Vision program. PLATO's objective is to characterize exoplanets and their host stars in the solar neighbourhood. While it builds on the heritage from CoRoT and Kepler, the major breakthrough will come from its strong focus on bright targets (mV <= 11). The PLATO targets will also include a large number of very bright (mV <= 8) and nearby stars.

The prime science goals of PLATO are: (i) the detection and characterization of exoplanetary systems of all kinds, including both the planets and their host stars, reaching down to small, terrestrial planets in the habitable zone; (ii) the identification of suitable targets for future, more detailed characterization, including a spectroscopic search for bio-markers in nearby habitable exoplanets.

These ambitious goals will be reached by ultra-high precision, long (few years), uninterrupted photometric monitoring in the visible of very large samples of bright stars, which can only be done from space. The resulting high quality light curves will be used on the one hand to detect planetary transits, as well as to measure their characteristics, and on the other hand to provide a seismic analysis of the host stars of the detected planets, from which precise measurements of their radii, masses, and ages will be derived.

The PLATO space-based data will be complemented by ground-based follow-up observations, in particular very precise radial velocity monitoring, which will be used to confirm the planetary nature of the detected events and to measure the planet masses.

The full set of parameters of exoplanetary systems will thus be measured, including all characteristics of the host stars and the orbits, radii, masses, and ages of the planets, allowing us to derive planet mean densities, and estimate their temperature and radiation environment. Finally, the knowledge of the age of the exoplanetary systems will allow us to put them in an evolutionary perspective. Title: FOREWORD Foreword Authors: Appourchaux, Thierry Bibcode: 2011JPhCS.271a1001A Altcode: Volume 271 (2011) of the Journal of Physics: Conference Series provides a record of the invited and contributed talks, and of the posters presented at the GONG2010-SoHO24 conference entitled 'A new era of seismology of the Sun and solar-like stars'. The conference was held from 27 June 2010 to 2 July 2010 in Aix-en-Provence, France. More than 120 scientists from all over the world attended the conference.

I would like to express my gratitude for the the financial support from the following organisations: Université Paris-Sud; the Centre National d'Etudes Spatiales (CNES); the Programme National des Relations Soleil-Terre (PNST) and the Programme National de Physique Stellaire (PNPS) (both programmes under the umbrella of the Institut National des Sciences de l'Univers, INSU); INSU of the Centre National de la Recherche Scientifique (CNRS); the SoHO project of the European Space Agency (ESA), and the Science Programme of ESA; the Global Oscillations Network Group (GONG); and finally the European Aeronautic Defence and Space Company (EADS).

The Scientific Organizing Committee comprised Thierry Appourchaux (chairman, Institut d'Astrophysique Spatiale, Orsay, France), Frank Hill (co-chairman, GONG / National Solar Observatory, Tucson, Arizona, United States), Annie Baglin (Observatoire de Paris-Meudon, France), William Chaplin (University of Birmingham, United Kingdom), Jørgen Christensen-Dalsgaard (Aarhus Universitet, Denmark), Thierry Corbard (Observatoire de la Côte d'Azur, Nice, France), Bernhard Fleck (European Space Agency), Laurent Gizon (Max-Planck-Institut für Sonnensystemforschung, Lindau, Germany), Travis Metcalfe (National Center for Atmospheric Research, Boulder, Colorado, United States), Michael Thompson (Sheffied University, United Kingdom; High Altitude Observatory, Boulder, Colorado, United States) and Jesper Schou (Stanford University, California, United States).

The Editorial Committee of these proceedings was composed of Thierry Appourchaux (chairman), Annie Baglin, William Chaplin, Jørgen Christensen-Dalsgaard, Laurent Gizon, Michael Thompson, Takashi Sekii (National Astronomical Observatory of Japan, Tokyo) and John Leibacher (IAS, Orsay, France; GONG / NSO, Tucson, Arizona, United States).

This volume consists of 86 articles organised in sections reflecting the scientific programme of the conference:

012001-012024 Local helioseismology 012025-012030 Solar diameter, irradiance and activity 012031-012044 Solar and stellar modelling 012045-012056 Low degree stellar seismology 012057-012063 First results from space missions 012064-012082 Convection, dynamo and flows 012083-012086 Prospective

All papers are freely accessible on the internet, in colour, at http://iopscience.iop.org/1742-6596/271/1, and an interactive picture of the conference is available in the attached PDF.

I am also grateful to the Local Organizing Committee for making this conference a success: Catherine Cougrand (secretary), Stéphane Caminade (web designer), Delphine Prival (administration) and Jean-Paul Rozet (logistics). I could not have done it without your help!

Last but not least, let me also thank the official photographer of the conference, Pierre Assus, for producing excellent photographs, including the group photo. Please feel free to send me an e-mail at Thierry.Appourchaux@ias.u-psud.fr if you would like copies of these pictures.

Thierry Appourchaux Editor

Orsay, France 24 December 2010

Conference photograph

IAS logo  Université Paris-Sud logo  CNRS logo  SOHO logo

ESA logo  NASA logo  Gong logo  EADS ASTRIUM logo Title: HD 46375: seismic and spectropolarimetric analysis of a young Sun hosting a Saturn-like planet Authors: Gaulme, P.; Deheuvels, S.; Weiss, W. W.; Mosser, B.; Moutou, C.; Bruntt, H.; Donati, J. -F.; Vannier, M.; Guillot, T.; Appourchaux, T.; Michel, E.; Auvergne, M.; Samadi, R.; Baudin, F.; Catala, C.; Baglin, A. Bibcode: 2010A&A...524A..47G Altcode: 2010arXiv1011.2671G Context. HD 46375 is known to host a Saturn-like exoplanet orbiting at 0.04 AU from its host star. Stellar light reflected by the planet was tentatively identified in the 34-day CoRoT run acquired in October-November 2008.
Aims: We constrain the properties of the magnetic field of HD 46375 based on spectropolarimetric observations with the NARVAL spectrograph at the Pic du Midi observatory. In addition, we use a high-resolution NARVAL flux spectrum to contrain the atmospheric parameters. With these constraints, we perform an asteroseismic analysis and modelling of HD 46375 using the frequencies extracted from the CoRoT light curve.
Methods: We used Zeeman Doppler imaging to reconstruct the magnetic map of the stellar surface. In the spectroscopic analysis we fitted isolated lines using 1D LTE atmosphere models. This analysis was used to constrain the effective temperature, surface gravity, and chemical composition of the star. To extract information about the p-mode oscillations, we used a technique based on the envelope autocorrelation function (EACF).
Results: From the Zeeman Doppler imaging observations, we observe a magnetic field of ≈ 5 Gauss. From the spectral analysis, HD 46375 is inferred to be an unevolved K0 type star with high metallicity [Fe/H] = +0.39. Owing to the relative faintness of the star (mhip = 8.05), the signal-to-noise ratio is too low to identify individual modes. However, we measure the p-mode excess power and large separation Δν0 = 153.0±0.7 μHz.
Conclusions: We are able do constrain the fundamental parameters of the star thanks to spectrometric and seismic analyses. We conclude that HD 46375 is similar to a young version of α Cen B. This work is of special interest because of its combination of exoplanetary science and asteroseismology, which are the subjects of the current Kepler mission and the proposed Plato mission.

The CoRoT space mission, launched on 2006 December 27, was developed and is operated by the CNES, with participation of the Science Programs of ESA, ESA's RSSD, Austria, Belgium, Brazil, Germany and Spain. Title: Asteroseismology of solar-type stars with Kepler I: Data analysis Authors: Karoff, C.; Chaplin, W. J.; Appourchaux, T.; Elsworth, Y.; Garcia, R. A.; Houdek, G.; Metcalfe, T. S.; Molenda-Żakowicz, J.; Monteiro, M. J. P. F. G.; Thompson, M. J.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Kjeldsen, H.; Basu, S.; Bedding, T. R.; Campante, T. L.; Eggenberger, P.; Fletcher, S. T.; Gaulme, P.; Handberg, R.; Hekker, S.; Martic, M.; Mathur, S.; Mosser, B.; Regulo, C.; Roxburgh, I. W.; Salabert, D.; Stello, D.; Verner, G. A.; Belkacem, K.; Biazzo, K.; Cunha, M. S.; Gruberbauer, M.; Guzik, J. A.; Kupka, F.; Leroy, B.; Ludwig, H. -G.; Mathis, S.; Noels, A.; Noyes, R. W.; Roca Cortes, T.; Roth, M.; Sato, K. H.; Schmitt, J.; Suran, M. D.; Trampedach, R.; Uytterhoeven, K.; Ventura, R. Bibcode: 2010AN....331..972K Altcode: 2010arXiv1005.0507K We report on the first asteroseismic analysis of solar-type stars observed by Kepler. Observations of three G-type stars, made at one-minute cadence during the first 33.5 days of science operations, reveal high signal-to-noise solar-like oscillation spectra in all three stars: About 20 modes of oscillation can clearly be distinguished in each star. We discuss the appearance of the oscillation spectra, including the presence of a possible signature of faculae, and the presence of mixed modes in one of the three stars. Title: Turbulent eddy-time-correlation in the solar convective zone Authors: Belkacem, K.; Samadi, R.; Goupil, M. J.; Baudin, F.; Salabert, D.; Appourchaux, T. Bibcode: 2010A&A...522L...2B Altcode: 2010arXiv1010.2682B Theoretical modeling of the driving processes of solar-like oscillations is a powerful way of understanding the properties of the convective zones of solar-type stars. In this framework, the description of the temporal correlation between turbulent eddies is an essential ingredient to model mode amplitudes. However, there is a debate between a Gaussian or Lorentzian description of the eddy-time correlation function (Samadi et al. 2003b, A&A, 403, 303; Chaplin et al. 2005, MNRAS, 360, 859). Indeed, a Gaussian description reproduces the low-frequency shape of the mode amplitude for the Sun, but is unsatisfactory from a theoretical point of view (Houdek 2010, Ap&SS, 328, 237) and leads to other disagreements with observations (Samadi et al. 2007, A&A, 463, 297). These are solved by using a Lorentzian description, but there the low-frequency shape of the solar observations is not correctly reproduced. We reconcile the two descriptions by adopting the sweeping approximation, which consists in assuming that the eddy-time-correlation function is dominated by the advection of eddies, in the inertial range, by energy-bearing eddies. Using a Lorentzian function together with a cut-off frequency derived from the sweeping assumption allows us to reproduce the low-frequency shape of the observations. This result also constitutes a validation of the sweeping assumption for highly turbulent flows as in the solar case. Title: A Precise Asteroseismic Age and Radius for the Evolved Sun-like Star KIC 11026764 Authors: Metcalfe, T. S.; Monteiro, M. J. P. F. G.; Thompson, M. J.; Molenda-Żakowicz, J.; Appourchaux, T.; Chaplin, W. J.; Doǧan, G.; Eggenberger, P.; Bedding, T. R.; Bruntt, H.; Creevey, O. L.; Quirion, P. -O.; Stello, D.; Bonanno, A.; Silva Aguirre, V.; Basu, S.; Esch, L.; Gai, N.; Di Mauro, M. P.; Kosovichev, A. G.; Kitiashvili, I. N.; Suárez, J. C.; Moya, A.; Piau, L.; García, R. A.; Marques, J. P.; Frasca, A.; Biazzo, K.; Sousa, S. G.; Dreizler, S.; Bazot, M.; Karoff, C.; Frandsen, S.; Wilson, P. A.; Brown, T. M.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Kjeldsen, H.; Campante, T. L.; Fletcher, S. T.; Handberg, R.; Régulo, C.; Salabert, D.; Schou, J.; Verner, G. A.; Ballot, J.; Broomhall, A. -M.; Elsworth, Y.; Hekker, S.; Huber, D.; Mathur, S.; New, R.; Roxburgh, I. W.; Sato, K. H.; White, T. R.; Borucki, W. J.; Koch, D. G.; Jenkins, J. M. Bibcode: 2010ApJ...723.1583M Altcode: 2010arXiv1010.4329M The primary science goal of the Kepler Mission is to provide a census of exoplanets in the solar neighborhood, including the identification and characterization of habitable Earth-like planets. The asteroseismic capabilities of the mission are being used to determine precise radii and ages for the target stars from their solar-like oscillations. Chaplin et al. published observations of three bright G-type stars, which were monitored during the first 33.5 days of science operations. One of these stars, the subgiant KIC 11026764, exhibits a characteristic pattern of oscillation frequencies suggesting that it has evolved significantly. We have derived asteroseismic estimates of the properties of KIC 11026764 from Kepler photometry combined with ground-based spectroscopic data. We present the results of detailed modeling for this star, employing a variety of independent codes and analyses that attempt to match the asteroseismic and spectroscopic constraints simultaneously. We determine both the radius and the age of KIC 11026764 with a precision near 1%, and an accuracy near 2% for the radius and 15% for the age. Continued observations of this star promise to reveal additional oscillation frequencies that will further improve the determination of its fundamental properties. Title: A comparison of frequentist and Bayesian inference: searching for low-frequency p modes and g modes in Sun-as-a-star data Authors: Broomhall, A. -M.; Chaplin, W. J.; Elsworth, Y.; Appourchaux, T.; New, R. Bibcode: 2010MNRAS.406..767B Altcode: 2010MNRAS.tmp..680B; 2010arXiv1004.4505B We describe and use two different statistical approaches to try and detect low-frequency solar oscillations in Sun-as-a-star data: a frequentist approach and a Bayesian approach. We have used frequentist statistics to search contemporaneous Sun-as-a-star data for coincident, statistically prominent features. However, we find that this approach leads to numerous false detections. We have also used Bayesian statistics to search for evidence of low-frequency p modes and g modes in Sun-as-a-star data. We describe how Bayesian statistics can be used to search near-contemporaneous data for coincident prominent features. Near-contemporaneous data were used to circumvent the difficulties in deriving probabilities that occur when common noise is present in the data. We find that the Bayesian approach, which is reliant on the assumptions made when determining the posterior probability, leads to significantly fewer false detections and those that are observed can be discredited using a priori knowledge. Therefore, we have more confidence in the mode candidates found with Bayesian statistics. Title: Possible detection of phase changes from the non-transiting planet HD 46375b by CoRoT Authors: Gaulme, P.; Vannier, M.; Guillot, T.; Mosser, B.; Mary, D.; Weiss, W. W.; Schmider, F. -X.; Bourguignon, S.; Deeg, H. J.; Régulo, C.; Aigrain, S.; Schneider, J.; Bruntt, H.; Deheuvels, S.; Donati, J. -F.; Appourchaux, T.; Auvergne, M.; Baglin, A.; Baudin, F.; Catala, C.; Michel, E.; Samadi, R. Bibcode: 2010A&A...518L.153G Altcode: 2010arXiv1011.2690G Context. The present work deals with the detection of phase changes in an exoplanetary system. HD 46375 is a solar analog known to host a non-transiting Saturn-mass exoplanet with a 3.0236 day period. It was observed by the CoRoT satellite for 34 days during the fall of 2008.
Aims: We attempt to identify at optical wavelengths, the changing phases of the planet as it orbits its star. We then try to improve the star model by means of a seismic analysis of the same light curve and the use of ground-based spectropolarimetric observations.
Methods: The data analysis relies on the Fourier spectrum and the folding of the time series.
Results: We find evidence of a sinusoidal signal compatible in terms of both amplitude and phase with light reflected by the planet. Its relative amplitude is Δ Fp/Fstar = [13.0, 26.8] ppm, implying an albedo A = [0.16, 0.33] or a dayside visible brightness temperature Tb ≃ [1880, 2030] K by assuming a radius R = 1.1 RJup and an inclination i = 45°. Its orbital phase differs from that of the radial-velocity signal by at most 2 σ_RV. However, the tiny planetary signal is strongly blended by another signal, which we attribute to a telluric signal with a 1 day period. We show that this signal is suppressed, but not eliminated, when using the time series for HD 46179 from the same CoRoT run as a reference.
Conclusions: This detection of reflected light from a non-transiting planet should be confirmable with a longer CoRoT observation of the same field. In any case, it demonstrates that non-transiting planets can be characterized using ultra-precise photometric lightcurves with present-day observations by CoRoT and Kepler. The combined detection of solar-type oscillations on the same targets (Gaulme et al. 2010a) highlights the overlap between exoplanetary science and asteroseismology and shows the high potential of a mission such as Plato.

The CoRoT space mission, launched on 2006 December 27, was developed and is operated by the CNES, with participation of the Science Programs of ESA, ESA's RSSD, Austria, Belgium, Brazil, Germany and Spain.Figure 6 is only available in electronic form at http://www.aanda.org Title: The solar-like CoRoT target HD 170987: spectroscopic and seismic observations Authors: Mathur, S.; García, R. A.; Catala, C.; Bruntt, H.; Mosser, B.; Appourchaux, T.; Ballot, J.; Creevey, O. L.; Gaulme, P.; Hekker, S.; Huber, D.; Karoff, C.; Piau, L.; Régulo, C.; Roxburgh, I. W.; Salabert, D.; Verner, G. A.; Auvergne, M.; Baglin, A.; Chaplin, W. J.; Elsworth, Y.; Michel, E.; Samadi, R.; Sato, K.; Stello, D. Bibcode: 2010A&A...518A..53M Altcode: 2010arXiv1004.4891M Context. The CoRoT mission is in its third year of observation and the data from the second long run in the galactic centre direction are being analysed. The solar-like oscillating stars that have been observed up to now have given some interesting results, specially concerning the amplitudes that are lower than predicted. We present here the results from the analysis of the star HD 170987.
Aims: The goal of this research work is to characterise the global parameters of HD 170987. We look for global seismic parameters such as the mean large separation, maximum amplitude of the modes, and surface rotation because the signal-to-noise ratio in the observations does not allow us to measure individual modes. We also aim to retrieve the parameters of the star and its chemical composition.
Methods: We studied the chemical composition of the star through ground-based observations performed with the NARVAL spectrograph. We used several methods to calculate the global parameters from the acoustic oscillations based on CoRoT data. The light curve of the star has been interpolated with inpainting algorithms to reduce the effect of data gaps.
Results: We found the power excess related to p modes in the range [400-1200] μHz with a mean large separation of 55.2 ± 0.8 μHz with a probability above 95 % that increases to 55.9 ± 0.2 μHz in a higher frequency range [500-1250] μHz and a rejection level of 1%. A hint of the variation of this quantity with frequency was also found. The rotation period of the star is estimated to be around 4.3 days with an inclination axis of i = 50° +20-13. We measured a bolometric amplitude per radial mode in a range [2.4-2.9] ppm around 1000 μHz. Finally we estimate the stellar mass with a grid of models, M = 1.43 ± 0.05 M_⊙, the radius, R = 1.96 ± 0.046 R_⊙, and the age ~2.4 Gyr.

The CoRoT space mission, launched on 2006 December 27, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA (RSSD and Science Programme), Germany and Spain. Title: The technical challenges of the Solar-Orbiter EUI instrument Authors: Halain, Jean-Philippe; Rochus, Pierre; Appourchaux, Thierry; Berghmans, David; Harra, Louise; Schühle, Udo; Auchère, Frédéric; Zhukov, Andrei; Renotte, Etienne; Defise, Jean-Marc; Rossi, Laurence; Fleury-Frenette, Karl; Jacques, Lionel; Hochedez, Jean-François; Ben Moussa, Ali Bibcode: 2010SPIE.7732E..0RH Altcode: 2010SPIE.7732E..20H The Extreme Ultraviolet Imager (EUI) onboard Solar Orbiter consists of a suite of two high-resolution imagers (HRI) and one dual-band full Sun imager (FSI) that will provide EUV and Lyman-α images of the solar atmospheric layers above the photosphere. The EUI instrument is based on a set of challenging new technologies allowing to reach the scientific objectives and to cope with the hard space environment of the Solar Orbiter mission. The mechanical concept of the EUI instrument is based on a common structure supporting the HRI and FSI channels, and a separated electronic box. A heat rejection baffle system is used to reduce the Sun heat load and provide a first protection level against the solar disk straylight. The spectral bands are selected by thin filters and multilayer mirror coatings. The detectors are 10μm pitch back illuminated CMOS Active Pixel Sensors (APS), best suited for the EUI science requirements and radiation hardness. This paper presents the EUI instrument concept and its major sub-systems. The current developments of the instrument technologies are also summarized. Title: Definition of an imaging spectrometer meeting the needs of UV solar physics Authors: Ruiz de Galarreta Fanjul, C.; Philippon, A.; Vial, J. -C.; Lemaire, P.; Maillard, J. -P.; Buisset, C.; Appourchaux, T.; Auchère, F. Bibcode: 2010SPIE.7732E..36R Altcode: 2010SPIE.7732E..99R The study of the outer solar atmosphere requires combining imaging and spectroscopy in the UV lines formed in the high chromosphere, the transition region and the corona. We start from the science requirements and we define the instrumental specifications in terms of field-of-view (FOV), spatial, temporal and spectral resolution and bandpass. We propose two different all-reflection optical architectures based on interferometric techniques: Spatial Heterodyne Spectroscopy (SHS); and Imaging Transform Spectrometer (IFTS). We describe the different set-ups and compare the potential performances of the two types of solutions, and discuss their feasibility. We conclude that IFTS appears to be the best solution, meeting the needs of UV solar physics. However, we point out the many difficulties to be encountered, especially as far as metrology is concerned. Title: Seismic and spectroscopic characterization of the solar-like pulsating CoRoT target HD 49385 Authors: Deheuvels, S.; Bruntt, H.; Michel, E.; Barban, C.; Verner, G.; Régulo, C.; Mosser, B.; Mathur, S.; Gaulme, P.; Garcia, R. A.; Boumier, P.; Appourchaux, T.; Samadi, R.; Catala, C.; Baudin, F.; Baglin, A.; Auvergne, M.; Roxburgh, I. W.; Pérez Hernández, F. Bibcode: 2010A&A...515A..87D Altcode: 2010arXiv1003.4368D Context. The star HD 49385 is the first G-type solar-like pulsator observed in the seismology field of the space telescope CoRoT. The satellite collected 137 days of high-precision photometric data on this star, confirming that it presents solar-like oscillations. HD 49385 was also observed in spectroscopy with the NARVAL spectrograph in January 2009.
Aims: Our goal is to characterize HD 49385 using both spectroscopic and seismic data.
Methods: The fundamental stellar parameters of HD 49385 are derived with the semi-automatic software VWA, and the projected rotational velocity is estimated by fitting synthetic profiles to isolated lines in the observed spectrum. A maximum likelihood estimation is used to determine the parameters of the observed p modes. We perform a global fit, in which modes are fitted simultaneously over nine radial orders, with degrees ranging from ℓ = 0 to ℓ = 3 (36 individual modes).
Results: Precise estimates of the atmospheric parameters (Teff, [M/H], log g) and of the ν sin i of HD 49385 are obtained. The seismic analysis of the star leads to a clear identification of the modes for degrees ℓ = 0,1,2. Around the maximum of the signal (ν ≃ 1013 μHz), some peaks are found significant and compatible with the expected characteristics of ℓ = 3 modes. Our fit yields robust estimates of the frequencies, linewidths and amplitudes of the modes. We find amplitudes of ~5.6 ± 0.8 ppm for radial modes at the maximum of the signal. The lifetimes of the modes range from one day (at high frequency) to a bit more than two days (at low frequency). Significant peaks are found outside the identified ridges and are fitted. They are attributed to mixed modes.

Based on data obtained from the CoRoT (Convection, Rotation and planetary Transits) space mission, developed by the French Space agency CNES in collaboration with the Science Programs of ESA, Austria, Belgium, Brazil, Germany and Spain.Based on data obtained using the Télescope Bernard Lyot at Observatoire du Pic du Midi, CNRS and Université Paul Sabatier, France. Title: An automated pipeline for asteroseismology based on the autocorrelation of stellar time series Authors: Mosser, Benoit; Appourchaux, Thierry Bibcode: 2010arXiv1006.5079M Altcode: The autocorrelation of an asteroseismic time series has been identified as a powerful tool capable of providing measurements of the large frequency separations. The performance of this method has been assessed and quantified by Mosser & Appourchaux (2009). We propose now an automated pipeline based on it and describe its performance. Title: A Multi-Site Campaign to Measure Solar-Like Oscillations in Procyon. II. Mode Frequencies Authors: Bedding, Timothy R.; Kjeldsen, Hans; Campante, Tiago L.; Appourchaux, Thierry; Bonanno, Alfio; Chaplin, William J.; Garcia, Rafael A.; Martić, Milena; Mosser, Benoit; Butler, R. Paul; Bruntt, Hans; Kiss, László L.; O'Toole, Simon J.; Kambe, Eiji; Ando, Hiroyasu; Izumiura, Hideyuki; Sato, Bun'ei; Hartmann, Michael; Hatzes, Artie; Barban, Caroline; Berthomieu, Gabrielle; Michel, Eric; Provost, Janine; Turck-Chièze, Sylvaine; Lebrun, Jean-Claude; Schmitt, Jerome; Bertaux, Jean-Loup; Benatti, Serena; Claudi, Riccardo U.; Cosentino, Rosario; Leccia, Silvio; Frandsen, Søren; Brogaard, Karsten; Glowienka, Lars; Grundahl, Frank; Stempels, Eric; Arentoft, Torben; Bazot, Michaël; Christensen-Dalsgaard, Jørgen; Dall, Thomas H.; Karoff, Christoffer; Lundgreen-Nielsen, Jens; Carrier, Fabien; Eggenberger, Patrick; Sosnowska, Danuta; Wittenmyer, Robert A.; Endl, Michael; Metcalfe, Travis S.; Hekker, Saskia; Reffert, Sabine Bibcode: 2010ApJ...713..935B Altcode: 2010arXiv1003.0052B We have analyzed data from a multi-site campaign to observe oscillations in the F5 star Procyon. The data consist of high-precision velocities that we obtained over more than three weeks with 11 telescopes. A new method for adjusting the data weights allows us to suppress the sidelobes in the power spectrum. Stacking the power spectrum in a so-called échelle diagram reveals two clear ridges, which we identify with even and odd values of the angular degree (l = 0 and 2, and l = 1 and 3, respectively). We interpret a strong, narrow peak at 446 μHz that lies close to the l = 1 ridge as a mode with mixed character. We show that the frequencies of the ridge centroids and their separations are useful diagnostics for asteroseismology. In particular, variations in the large separation appear to indicate a glitch in the sound-speed profile at an acoustic depth of ~1000 s. We list frequencies for 55 modes extracted from the data spanning 20 radial orders, a range comparable to the best solar data, which will provide valuable constraints for theoretical models. A preliminary comparison with published models shows that the offset between observed and calculated frequencies for the radial modes is very different for Procyon than for the Sun and other cool stars. We find the mean lifetime of the modes in Procyon to be 1.29+0.55 -0.49 days, which is significantly shorter than the 2-4 days seen in the Sun. Title: The Asteroseismic Potential of Kepler: First Results for Solar-Type Stars Authors: Chaplin, W. J.; Appourchaux, T.; Elsworth, Y.; García, R. A.; Houdek, G.; Karoff, C.; Metcalfe, T. S.; Molenda-Żakowicz, J.; Monteiro, M. J. P. F. G.; Thompson, M. J.; Brown, T. M.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Kjeldsen, H.; Borucki, W. J.; Koch, D.; Jenkins, J. M.; Ballot, J.; Basu, S.; Bazot, M.; Bedding, T. R.; Benomar, O.; Bonanno, A.; Brandão, I. M.; Bruntt, H.; Campante, T. L.; Creevey, O. L.; Di Mauro, M. P.; Doǧan, G.; Dreizler, S.; Eggenberger, P.; Esch, L.; Fletcher, S. T.; Frandsen, S.; Gai, N.; Gaulme, P.; Handberg, R.; Hekker, S.; Howe, R.; Huber, D.; Korzennik, S. G.; Lebrun, J. C.; Leccia, S.; Martic, M.; Mathur, S.; Mosser, B.; New, R.; Quirion, P. -O.; Régulo, C.; Roxburgh, I. W.; Salabert, D.; Schou, J.; Sousa, S. G.; Stello, D.; Verner, G. A.; Arentoft, T.; Barban, C.; Belkacem, K.; Benatti, S.; Biazzo, K.; Boumier, P.; Bradley, P. A.; Broomhall, A. -M.; Buzasi, D. L.; Claudi, R. U.; Cunha, M. S.; D'Antona, F.; Deheuvels, S.; Derekas, A.; García Hernández, A.; Giampapa, M. S.; Goupil, M. J.; Gruberbauer, M.; Guzik, J. A.; Hale, S. J.; Ireland, M. J.; Kiss, L. L.; Kitiashvili, I. N.; Kolenberg, K.; Korhonen, H.; Kosovichev, A. G.; Kupka, F.; Lebreton, Y.; Leroy, B.; Ludwig, H. -G.; Mathis, S.; Michel, E.; Miglio, A.; Montalbán, J.; Moya, A.; Noels, A.; Noyes, R. W.; Pallé, P. L.; Piau, L.; Preston, H. L.; Roca Cortés, T.; Roth, M.; Sato, K. H.; Schmitt, J.; Serenelli, A. M.; Silva Aguirre, V.; Stevens, I. R.; Suárez, J. C.; Suran, M. D.; Trampedach, R.; Turck-Chièze, S.; Uytterhoeven, K.; Ventura, R.; Wilson, P. A. Bibcode: 2010ApJ...713L.169C Altcode: 2010arXiv1001.0506C We present preliminary asteroseismic results from Kepler on three G-type stars. The observations, made at one-minute cadence during the first 33.5 days of science operations, reveal high signal-to-noise solar-like oscillation spectra in all three stars: about 20 modes of oscillation may be clearly distinguished in each star. We discuss the appearance of the oscillation spectra, use the frequencies and frequency separations to provide first results on the radii, masses, and ages of the stars, and comment in the light of these results on prospects for inference on other solar-type stars that Kepler will observe. Title: Kepler Asteroseismology Program: Introduction and First Results Authors: Gilliland, Ronald L.; Brown, Timothy M.; Christensen-Dalsgaard, Jørgen; Kjeldsen, Hans; Aerts, Conny; Appourchaux, Thierry; Basu, Sarbani; Bedding, Timothy R.; Chaplin, William J.; Cunha, Margarida S.; De Cat, Peter; De Ridder, Joris; Guzik, Joyce A.; Handler, Gerald; Kawaler, Steven; Kiss, László; Kolenberg, Katrien; Kurtz, Donald W.; Metcalfe, Travis S.; Monteiro, Mario J. P. F. G.; Szabó, Robert; Arentoft, Torben; Balona, Luis; Debosscher, Jonas; Elsworth, Yvonne P.; Quirion, Pierre-Olivier; Stello, Dennis; Suárez, Juan Carlos; Borucki, William J.; Jenkins, Jon M.; Koch, David; Kondo, Yoji; Latham, David W.; Rowe, Jason F.; Steffen, Jason H. Bibcode: 2010PASP..122..131G Altcode: 2010arXiv1001.0139G Asteroseismology involves probing the interiors of stars and quantifying their global properties, such as radius and age, through observations of normal modes of oscillation. The technical requirements for conducting asteroseismology include ultrahigh precision measured in photometry in parts per million, as well as nearly continuous time series over weeks to years, and cadences rapid enough to sample oscillations with periods as short as a few minutes. We report on results from the first 43 days of observations, in which the unique capabilities of Kepler in providing a revolutionary advance in asteroseismology are already well in evidence. The Kepler asteroseismology program holds intrinsic importance in supporting the core planetary search program through greatly enhanced knowledge of host star properties, and extends well beyond this to rich applications in stellar astrophysics. Title: The quest for the solar g modes Authors: Appourchaux, T.; Belkacem, K.; Broomhall, A. -M.; Chaplin, W. J.; Gough, D. O.; Houdek, G.; Provost, J.; Baudin, F.; Boumier, P.; Elsworth, Y.; García, R. A.; Andersen, B. N.; Finsterle, W.; Fröhlich, C.; Gabriel, A.; Grec, G.; Jiménez, A.; Kosovichev, A.; Sekii, T.; Toutain, T.; Turck-Chièze, S. Bibcode: 2010A&ARv..18..197A Altcode: 2010A&ARv.tmp....1A; 2009arXiv0910.0848A Solar gravity modes (or g modes)—oscillations of the solar interior on which buoyancy acts as the restoring force—have the potential to provide unprecedented inference on the structure and dynamics of the solar core, inference that is not possible with the well-observed acoustic modes (or p modes). The relative high amplitude of the g-mode eigenfunctions in the core and the evanesence of the modes in the convection zone make the modes particularly sensitive to the physical and dynamical conditions in the core. Owing to the existence of the convection zone, the g modes have very low amplitudes at photospheric levels, which makes the modes extremely hard to detect. In this article, we review the current state of play regarding attempts to detect g modes. We review the theory of g modes, including theoretical estimation of the g-mode frequencies, amplitudes and damping rates. Then we go on to discuss the techniques that have been used to try to detect g modes. We review results in the literature, and finish by looking to the future, and the potential advances that can be made—from both data and data-analysis perspectives—to give unambiguous detections of individual g modes. The review ends by concluding that, at the time of writing, there is indeed a consensus amongst the authors that there is currently no undisputed detection of solar g modes. Title: The CoRoT target HD 49933 . II. Comparison of theoretical mode amplitudes with observations Authors: Samadi, R.; Ludwig, H. -G.; Belkacem, K.; Goupil, M. J.; Benomar, O.; Mosser, B.; Dupret, M. -A.; Baudin, F.; Appourchaux, T.; Michel, E. Bibcode: 2010A&A...509A..16S Altcode: 2009arXiv0910.4037S Context. The seismic data obtained by CoRoT for the star HD 49933 enable us for the first time to measure directly the amplitudes and linewidths of solar-like oscillations for a star other than the Sun. From those measurements it is possible, as was done for the Sun, to constrain models of the excitation of acoustic modes by turbulent convection.
Aims: We compare a stochastic excitation model described in Paper I with the asteroseismology data for HD 49933, a star that is rather metal poor and significantly hotter than the Sun.
Methods: Using the seismic determinations of the mode linewidths detected by CoRoT for HD 49933 and the theoretical mode excitation rates computed in Paper I for the specific case of HD 49933, we derive the expected surface velocity amplitudes of the acoustic modes detected in HD 49933. Using a calibrated quasi-adiabatic approximation relating the mode amplitudes in intensity to those in velocity, we derive the expected values of the mode amplitude in intensity.
Results: Except at rather high frequency, our amplitude calculations are within 1-σ error bars of the mode surface velocity spectrum derived with the HARPS spectrograph. The same is found with respect to the mode amplitudes in intensity derived for HD 49933 from the CoRoT data. On the other hand, at high frequency (ν ⪆ 1.9 mHz), our calculations depart significantly from the CoRoT and HARPS measurements. We show that assuming a solar metal abundance rather than the actual metal abundance of the star would result in a larger discrepancy with the seismic data. Furthermore, we present calculations which assume the “new” solar chemical mixture to be in better agreement with the seismic data than those that assumed the “old” solar chemical mixture.
Conclusions: These results validate in the case of a star significantly hotter than the Sun and α Cen A the main assumptions in the model of stochastic excitation. However, the discrepancies seen at high frequency highlight some deficiencies of the modelling, whose origin remains to be understood. We also show that it is important to take the surface metal abundance of the solar-like pulsators into account.

The CoRoT space mission, launched on December 27 2006, has been developped and is operated by CNES, with the contribution of Austria, Belgium, Brasil, ESA, Germany and Spain. Title: SIAMOIS, asteroseismolgy at Dome C after CoRoT Authors: Mosser, B.; Buey, T.; Appourchaux, T.; Charpinet, S.; Mathias, P.; Schmider, F. X.; Maillard, J. P.; Siamois Team Bibcode: 2010EAS....40..381M Altcode: SIAMOIS is a ground-based asteroseismology project, to pursue velocity measurements from the Dome C Concordia station in Antarctica. Dome C appears to be the ideal place for ground-based asteroseismic observations as it is capable of delivering a duty cycle as high as 87% during the three-month long polar night. This high duty cycle, a crucial point for asteroseismology, is comparable to the best space-borne observations. We present the quality of the SIAMOIS project, that yields to its selection as top priority by the working group of ARENA dedicated to “Time series observations from Dome C”. We show that, after CoRoT, SIAMOIS proposes a large scientific case, that extends the pioneering work and great discoveries of CoRoT. We depict a few important ingredients of the project: full automation, space-like philosophy, and compatibility with the current facilities at the Concordia station. SIAMOIS has no real competitor before at least 2016/2017, and can be considered as a pathfinder for many important issues concerning astronomical observations at Dome C. Title: On detecting the large separation in the autocorrelation of stellar oscillation times series Authors: Mosser, B.; Appourchaux, T. Bibcode: 2009A&A...508..877M Altcode: 2009arXiv0909.0782M Context: The observations carried out by the space missions CoRoT and Kepler provide a large set of asteroseismic data. Their analysis requires an efficient procedure first to determine if a star reliably shows solar-like oscillations, second to measure the so-called large separation, third to estimate the asteroseismic information that can be retrieved from the Fourier spectrum.
Aims: In this paper we develop a procedure based on the autocorrelation of the seismic Fourier spectrum that is capable of providing measurements of the large and small frequency separations. The performance of the autocorrelation method needs to be assessed and quantified. We therefore searched for criteria able to predict the output that one can expect from the analysis by autocorrelation of a seismic time series.
Methods: First, the autocorrelation is properly scaled to take into account the contribution of white noise. Then we use the null hypothesis H0 test to assess the reliability of the autocorrelation analysis. Calculations based on solar and CoRoT time series are performed to quantify the performance as a function of the amplitude of the autocorrelation signal.
Results: We obtain an empirical relation for the performance of the autocorrelation method. We show that the precision of the method increases with the observation length, and with the mean seismic amplitude-to-background ratio of the pressure modes to the power 1.5 ± 0.05. We propose an automated determination of the large separation, whose reliability is quantified by the H0 test. We apply this method to analyze red giants observed by CoRoT. We estimate the expected performance for photometric time series of the Kepler mission. We demonstrate that the method makes it possible to distinguish ℓ = 0 from ℓ = 1 modes.
Conclusions: The envelope autocorrelation function (EACF) has proven to be very powerful for the determination of the large separation in noisy asteroseismic data, since it enables us to quantify the precision of the performance of different measurements: mean large separation, variation of the large separation with frequency, small separation and degree identification.

The CoRoT space mission, launched on 2006 December 27, was developed and is operated by the CNES, with participation of the Science Programs of ESA, ESA's RSSD, Austria, Belgium, Brazil, Germany and Spain. Title: A fresh look at the seismic spectrum of HD49933: analysis of 180 days of CoRoT photometry Authors: Benomar, O.; Baudin, F.; Campante, T. L.; Chaplin, W. J.; García, R. A.; Gaulme, P.; Toutain, T.; Verner, G. A.; Appourchaux, T.; Ballot, J.; Barban, C.; Elsworth, Y.; Mathur, S.; Mosser, B.; Régulo, C.; Roxburgh, I. W.; Auvergne, M.; Baglin, A.; Catala, C.; Michel, E.; Samadi, R. Bibcode: 2009A&A...507L..13B Altcode: 2009arXiv0910.3060B Context: Solar-like oscillations have now been observed in several stars, thanks to ground-based spectroscopic observations and space-borne photometry. CoRoT, which has been in orbit since December 2006, has observed the star HD49933 twice. The oscillation spectrum of this star has proven difficult to interpret.
Aims: Thanks to a new timeseries provided by CoRoT, we aim to provide a robust description of the oscillations in HD49933, i.e., to identify the degrees of the observed modes, and to measure mode frequencies, widths, amplitudes and the average rotational splitting.
Methods: Several methods were used to model the Fourier spectrum: Maximum Likelihood Estimators and Bayesian analysis using Markov Chain Monte-Carlo techniques.
Results: The different methods yield consistent result, and allow us to make a robust identification of the modes and to extract precise mode parameters. Only the rotational splitting remains difficult to estimate precisely, but is clearly relatively large (several μHz in size).

The CoRoT space mission, launched on 2006 December 27, was developed and is operated by the CNES, with participation of the Science Programs of ESA, ESA's RSSD, Austria, Belgium, Brazil, Germany and Spain.

Figures 5-9 and Table 2 are only available in electronic form at http://www.aanda.org Title: The solar-like oscillations of HD 49933: a Bayesian approach Authors: Benomar, O.; Appourchaux, T.; Baudin, F. Bibcode: 2009A&A...506...15B Altcode: Context: Asteroseismology has entered a new era with the availability of continuous observations from space-borne missions such as MOST, CoRoT and Kepler. However, the low amplitude and the complexity of the observed spectrum make the exploitation of these data sets difficult.
Aims: The use of robust methods to estimate the parameters of stellar oscillation eigenmodes is necessary to fully exploit these new data sets. These parameters include in particular the frequency, the width and the energy of the eigenmodes, all being required for a seismic interpretation of the stellar internal structure or excitation of the eigenmodes.
Methods: A Bayesian approach, coupled with a Markov chain Monte Carlo (MCMC) algorithm, is presented. Such a method allows the use of a priori knowledge to improve the parameter estimation. It also provides complete information on the probability distribution of the fitted parameters. The method is tested on simulated time series and then applied to CoRoT observations of HD 49933.
Results: The simulated time series allow the validation of the method for conditions similar to those of the observations in terms of spectral complexity and signal-to-noise ratio. However, a very important problem in the analysis of the HD 49933 mode spectrum is the l degree identification of the modes. The degree identification has little impact on the large frequency separation, rotational splitting, energy and width estimation, whereas individual frequencies and the star inclination angle evaluation are strongly affected. From a statistical point of view, we provide a quantitative ranking of the four models considered. The most probable model includes only modes of degree 0 and 1. Two other models include modes with degree up to 2 and have a non negligible level of significance. The last model includes modes of degree 0 and 1 but has an alternate degree identification and can be definitively rejected. In conclusion, the significance of the resulting probabilities is not sufficient to draw a definite conclusion.

The CoRoT space mission, launched on

2006 December 27, was developed and is operated by the CNES, with

participation of the Science Programs of ESA, ESA's RSSD, Austria,

Belgium, Brazil, Germany and Spain.

Tables 10 to 15 and Figs. 11, 12 are only available in electronic form at http://www.aanda.org Title: The CoRoT target HD 175726: an active star with weak solar-like oscillations Authors: Mosser, B.; Michel, E.; Appourchaux, T.; Barban, C.; Baudin, F.; Boumier, P.; Bruntt, H.; Catala, C.; Deheuvels, S.; García, R. A.; Gaulme, P.; Regulo, C.; Roxburgh, I.; Samadi, R.; Verner, G.; Auvergne, M.; Baglin, A.; Ballot, J.; Benomar, O.; Mathur, S. Bibcode: 2009A&A...506...33M Altcode: 2009arXiv0908.2244M Context: The CoRoT short runs give us the opportunity to observe a large variety of late-type stars through their solar-like oscillations. We report observations of the star HD 175726 that lasted for 27 days during the first short run of the mission. The time series reveals a high-activity signal and the power spectrum presents an excess due to solar-like oscillations with a low signal-to-noise ratio.
Aims: Our aim is to identify the most efficient tools to extract as much information as possible from the power density spectrum.
Methods: The most productive method appears to be the autocorrelation of the time series, calculated as the spectrum of the filtered spectrum. This method is efficient, very rapid computationally, and will be useful for the analysis of other targets, observed with CoRoT or with forthcoming missions such as Kepler and Plato.
Results: The mean large separation has been measured to be 97.2±0.5 μHz, slightly below the expected value determined from solar scaling laws. We also show strong evidence for variation of the large separation with frequency. The bolometric mode amplitude is only 1.7±0.25 ppm for radial modes, which is 1.7 times less than expected. Due to the low signal-to-noise ratio, mode identification is not possible for the available data set of HD 175726.

The CoRoT space mission, launched on 2006 December 27, was developed and is operated by the CNES, with participation of the Science Programs of ESA, ESAs RSSD, Austria, Belgium, Brazil, Germany and Spain. Title: Mode width fitting with a simple Bayesian approach. Application to CoRoT targets HD 181420 and HD 49933 Authors: Gaulme, P.; Appourchaux, T.; Boumier, P. Bibcode: 2009A&A...506....7G Altcode: 2010arXiv1011.2675G Aims: We investigate the asteroseismology of two solar-like targets as observed with the CoRoT satellite, with particular attention paid to the mode fitting. HD 181420 and HD 49933 are typical CoRoT solar-like targets (156 and 60-day runs). The low signal-to-noise ratio (SNR) of about 3{-}10 prevents us from unambiguously identifying the individual oscillation modes. In particular, convergence problems appear at the edges of the oscillation spectrum.
Methods: We apply a Bayesian approach to the analysis of these data. We compare the global fitting of the power spectra obtained by the classical maximum likelihood (MLE) and the maximum a posteriori (MAP) estimators.
Results: We examine the impact of the choice of the priors upon the fitted parameters. We also propose to reduce the number of free parameters in the fitting, by replacing the individual estimate of mode height associated with each overtone by a continuous function of frequency (Gaussian profile).
Conclusions: The MAP appears as a powerful tool to constrain the global fits, but it must be used carefully and only with reliable priors. The mode width of the stars increases with the frequency over all the oscillation spectrum.

The CoRoT space mission, launched on 2006 December 27, was developed and is operated by the CNES, with participation of the Science Programs of ESA, ESA's RSSD, Austria, Belgium, Brazil, Germany and Spain. Title: On posterior probability and significance level: application to the power spectrum of HD 49 933 observed by CoRoT Authors: Appourchaux, T.; Samadi, R.; Dupret, M. -A. Bibcode: 2009A&A...506....1A Altcode: 2009arXiv0906.0864A Context: The CoRoT mission provides asteroseismic data of very high quality allowing one to adopt new statistical approaches for mode detection in power spectra, especially with respect to testing the null hypothesis (H{0}, which assumes that what is observed is pure noise).
Aims: We emphasize that the significance level when rejecting the null hypothesis can lead to the incorrect conclusion that the H{0} hypothesis is unlikely to occur at that significance level. We demonstrate that the significance level is unrelated to the posterior probability of H{0}, given the observed data set, and that this posterior probability is very much higher than implied by the significance level.
Methods: We use Bayes theorem to derive the posterior probability of that H{0} is true assuming an alternative hypothesis H{1} that a mode is present, taking some prior for the mode height, mode amplitude and linewidth.
Results: We compute the posterior probability of H{0} for the p modes detected on HD 49 933 by CoRoT.
Conclusions: We conclude that the posterior probability of H{0} provide a much more conservative quantification of the mode detection than the significance level. This framework can be applied to any similar stellar power spectra obtained to complete asteroseismology.

The CoRoT space mission, launched on

2006 December 27, was developed and is operated by the CNES, with

participation of the Science Programs of ESA, ESA's RSSD, Austria,

Belgium, Brazil, Germany and Spain. Title: The CoRoT satellite in flight: description and performance Authors: Auvergne, M.; Bodin, P.; Boisnard, L.; Buey, J. -T.; Chaintreuil, S.; Epstein, G.; Jouret, M.; Lam-Trong, T.; Levacher, P.; Magnan, A.; Perez, R.; Plasson, P.; Plesseria, J.; Peter, G.; Steller, M.; Tiphène, D.; Baglin, A.; Agogué, P.; Appourchaux, T.; Barbet, D.; Beaufort, T.; Bellenger, R.; Berlin, R.; Bernardi, P.; Blouin, D.; Boumier, P.; Bonneau, F.; Briet, R.; Butler, B.; Cautain, R.; Chiavassa, F.; Costes, V.; Cuvilho, J.; Cunha-Parro, V.; de Oliveira Fialho, F.; Decaudin, M.; Defise, J. -M.; Djalal, S.; Docclo, A.; Drummond, R.; Dupuis, O.; Exil, G.; Fauré, C.; Gaboriaud, A.; Gamet, P.; Gavalda, P.; Grolleau, E.; Gueguen, L.; Guivarc'h, V.; Guterman, P.; Hasiba, J.; Huntzinger, G.; Hustaix, H.; Imbert, C.; Jeanville, G.; Johlander, B.; Jorda, L.; Journoud, P.; Karioty, F.; Kerjean, L.; Lafond, L.; Lapeyrere, V.; Landiech, P.; Larqué, T.; Laudet, P.; Le Merrer, J.; Leporati, L.; Leruyet, B.; Levieuge, B.; Llebaria, A.; Martin, L.; Mazy, E.; Mesnager, J. -M.; Michel, J. -P.; Moalic, J. -P.; Monjoin, W.; Naudet, D.; Neukirchner, S.; Nguyen-Kim, K.; Ollivier, M.; Orcesi, J. -L.; Ottacher, H.; Oulali, A.; Parisot, J.; Perruchot, S.; Piacentino, A.; Pinheiro da Silva, L.; Platzer, J.; Pontet, B.; Pradines, A.; Quentin, C.; Rohbeck, U.; Rolland, G.; Rollenhagen, F.; Romagnan, R.; Russ, N.; Samadi, R.; Schmidt, R.; Schwartz, N.; Sebbag, I.; Smit, H.; Sunter, W.; Tello, M.; Toulouse, P.; Ulmer, B.; Vandermarcq, O.; Vergnault, E.; Wallner, R.; Waultier, G.; Zanatta, P. Bibcode: 2009A&A...506..411A Altcode: 2009arXiv0901.2206A Context: CoRoT is a space telescope dedicated to stellar seismology and the search for extrasolar planets. The mission is led by the CNES in association with French laboratories and has a large international participation. The European Space Agency (ESA), Austria, Belgium, and Germany contribute to the payload, and Spain and Brazil contribute to the ground segment. Development of the spacecraft, which is based on a PROTEUS low earth orbit (LEO) recurrent platform, commenced in October 2000, and the satellite was launched on December 27, 2006.
Aims: The instrument and platform characteristics prior to launch have been described in ESA publication (SP-1306). In the present paper we explain the behaviour in flight, based on raw and corrected data.
Methods: Five runs have been completed since January 2007. The data used here are essentially those acquired during the commissioning phase and from a long run that lasted 146 days. These enable us to give a complete overview of the instrument and platform behaviour for all environmental conditions. The ground based data processing is not described in detail because the most important method has been published elsewhere.
Results: We show that the performance specifications are easily satisfied when the environmental conditions are favourable. Most of the perturbations, hence data corrections, are related to LEO perturbations: high energy particles inside the South Atlantic Anomaly (SAA), eclipses and temperature variations, and line of sight fluctuations due to the attitude control system. Straylight due to the reflected light from the earth, which is controlled by the telescope and baffle design, appears to be negligible.

The CoRoT space mission, launched on December 27th 2006, has been developed and is operated by CNES, with contributions from Austria, Belgium, Brazil, ESA, Germany and Spain.

Four French laboratories associated with the CNRS (LESIA, LAM, IAS, OMP) collaborate with CNES on the satellite development. The authors are grateful to Ian Roxburgh for a careful reading of the manuscript. Title: Hydrodynamical simulations of convection-related stellar micro-variability. II. The enigmatic granulation background of the CoRoT target HD 49933 Authors: Ludwig, H. -G.; Samadi, R.; Steffen, M.; Appourchaux, T.; Baudin, F.; Belkacem, K.; Boumier, P.; Goupil, M. -J.; Michel, E. Bibcode: 2009A&A...506..167L Altcode: 2009arXiv0905.2695L Context: Local-box hydrodynamical model atmospheres provide statistical information about a star's emergent radiation field which allows one to predict the level of its granulation-related micro-variability. Space-based photometry is now sufficiently accurate to test model predictions.
Aims: We aim to model the photometric granulation background of HD 49933 as well as the Sun, and compare the predictions to the measurements obtained by the <sf>CoRoT</sf> and <sf>SOHO</sf> satellite missions.
Methods: We construct hydrodynamical model atmospheres representing HD 49933 and the Sun, and use a previously developed scaling technique to obtain the observable disk-integrated brightness fluctuations. We further performed exploratory magneto-hydrodynamical simulations to gauge the impact of small scale magnetic fields on the synthetic light-curves.
Results: We find that the granulation-related brightness fluctuations depend on metallicity. We obtain a satisfactory correspondence between prediction and observation for the Sun, validating our approach. For HD 49933, we arrive at a significant over-estimation by a factor of two to three in total power. Locally generated magnetic fields are unlikely to be responsible, otherwise existing fields would need to be rather strong to sufficiently suppress the granulation signal. Presently suggested updates on the fundamental stellar parameters do not improve the correspondence; however, an ad-hoc increase of the HD 49933 surface gravity by about 0.2 dex would eliminate most of the discrepancy.
Conclusions: We diagnose a puzzling discrepancy between the predicted and observed granulation background in HD 49933, with only rather ad-hoc ideas for remedies at hand.

The <sf>CoRoT</sf> space mission, launched on December 27th 2006, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA, Germany and Spain. CIFIST Marie Curie Excellence Team. Title: Solar-like oscillations in HD 181420: data analysis of 156 days of CoRoT data Authors: Barban, C.; Deheuvels, S.; Baudin, F.; Appourchaux, T.; Auvergne, M.; Ballot, J.; Boumier, P.; Chaplin, W. J.; García, R. A.; Gaulme, P.; Michel, E.; Mosser, B.; Régulo, C.; Roxburgh, I. W.; Verner, G.; Baglin, A.; Catala, C.; Samadi, R.; Bruntt, H.; Elsworth, Y.; Mathur, S. Bibcode: 2009A&A...506...51B Altcode: Context: The estimate of solar-like oscillation properties, such as their frequencies, amplitudes and lifetimes, is challenging because of their low amplitudes and will benefit from long and uninterrupted observing runs. The space telescope CoRoT allows us to obtain high-performance photometric data over a long and quasi continuous period. Among its main targets are stars for which we expect solar-like oscillations.
Aims: HD 181420, an F2 main sequence star, has been observed by CoRoT during its first long run covering about 156 days. With this unprecedently high-quality set of data, our aim is to derive the p-mode parameters that can be used to probe the stellar interior.
Methods: The CoRoT data obtained on HD 181420 is analysed using a classical Fourier approach for the search for the p mode signature. The p-mode parameters are then derived using global fitting of the power spectrum by a Lorentzian model, as used widely in the solar case.
Results: From the p-mode frequencies, the mean value of the large spacing is estimated to be 75 {μ Hz}. The p-mode amplitudes are slightly less than 4 ppm with a line width of about 8 {μ Hz} at the maximum of the p modes. The inclination angle is estimated to be around 45 °. The large mode line-width combined with the observed mode spacing make it difficult to identify the ℓ=2 modes and to estimate the rotational splitting. We explore two scenarios for the identification of the modes.

The CoRoT space mission, launched on 2006 December 27, was delopped and is operated by the CNES with participation of the Science Programs of ESA; ESA's RSSD, Austria, Belgium, Brazil, Germany and Spain. Title: Solar-like oscillations with low amplitude in the CoRoT target HD 181906 Authors: García, R. A.; Régulo, C.; Samadi, R.; Ballot, J.; Barban, C.; Benomar, O.; Chaplin, W. J.; Gaulme, P.; Appourchaux, T.; Mathur, S.; Mosser, B.; Toutain, T.; Verner, G. A.; Auvergne, M.; Baglin, A.; Baudin, F.; Boumier, P.; Bruntt, H.; Catala, C.; Deheuvels, S.; Elsworth, Y.; Jiménez-Reyes, S. J.; Michel, E.; Pérez Hernández, F.; Roxburgh, I. W.; Salabert, D. Bibcode: 2009A&A...506...41G Altcode: 2009arXiv0907.0608G Context: The F8 star HD 181906 (effective temperature ∼6300 K) was observed for 156 days by the CoRoT satellite during the first long run in the direction of the galactic centre. Analysis of the data reveals a spectrum of solar-like acoustic oscillations. However, the faintness of the target (mv = 7.65) means the signal-to-noise (S/N) in the acoustic modes is quite low, and this low S/N leads to complications in the analysis.
Aims: We extract global variables of the star, as well as key parameters of the p modes observed in the power spectrum of the lightcurve.
Methods: The power spectrum of the lightcurve, a wavelet transform and spot fitting were used to obtain the average rotation rate of the star and its inclination angle. Then, the autocorrelation of the power spectrum and the power spectrum of the power spectrum were used to properly determine the large separation. Finally, estimations of the mode parameters were done by maximizing the likelihood of a global fit, where several modes were fit simultaneously.
Results: We have been able to infer the mean surface rotation rate of the star (~4 μHz) with indications of the presence of surface differential rotation, the large separation of the p modes (~87 μHz), hence also the “ridges” corresponding to overtones of the acoustic modes.

CoRoT (Convection, Rotation and planetary Transits) is a minisatellite developed by the French Space agency CNES in collaboration with the Science Programmes of ESA, Austria, Belgium, Brazil, Germany and Spain. Title: Transiting exoplanets from the CoRoT space mission. VIII. CoRoT-7b: the first super-Earth with measured radius Authors: Léger, A.; Rouan, D.; Schneider, J.; Barge, P.; Fridlund, M.; Samuel, B.; Ollivier, M.; Guenther, E.; Deleuil, M.; Deeg, H. J.; Auvergne, M.; Alonso, R.; Aigrain, S.; Alapini, A.; Almenara, J. M.; Baglin, A.; Barbieri, M.; Bruntt, H.; Bordé, P.; Bouchy, F.; Cabrera, J.; Catala, C.; Carone, L.; Carpano, S.; Csizmadia, Sz.; Dvorak, R.; Erikson, A.; Ferraz-Mello, S.; Foing, B.; Fressin, F.; Gandolfi, D.; Gillon, M.; Gondoin, Ph.; Grasset, O.; Guillot, T.; Hatzes, A.; Hébrard, G.; Jorda, L.; Lammer, H.; Llebaria, A.; Loeillet, B.; Mayor, M.; Mazeh, T.; Moutou, C.; Pätzold, M.; Pont, F.; Queloz, D.; Rauer, H.; Renner, S.; Samadi, R.; Shporer, A.; Sotin, Ch.; Tingley, B.; Wuchterl, G.; Adda, M.; Agogu, P.; Appourchaux, T.; Ballans, H.; Baron, P.; Beaufort, T.; Bellenger, R.; Berlin, R.; Bernardi, P.; Blouin, D.; Baudin, F.; Bodin, P.; Boisnard, L.; Boit, L.; Bonneau, F.; Borzeix, S.; Briet, R.; Buey, J. -T.; Butler, B.; Cailleau, D.; Cautain, R.; Chabaud, P. -Y.; Chaintreuil, S.; Chiavassa, F.; Costes, V.; Cuna Parrho, V.; de Oliveira Fialho, F.; Decaudin, M.; Defise, J. -M.; Djalal, S.; Epstein, G.; Exil, G. -E.; Fauré, C.; Fenouillet, T.; Gaboriaud, A.; Gallic, A.; Gamet, P.; Gavalda, P.; Grolleau, E.; Gruneisen, R.; Gueguen, L.; Guis, V.; Guivarc'h, V.; Guterman, P.; Hallouard, D.; Hasiba, J.; Heuripeau, F.; Huntzinger, G.; Hustaix, H.; Imad, C.; Imbert, C.; Johlander, B.; Jouret, M.; Journoud, P.; Karioty, F.; Kerjean, L.; Lafaille, V.; Lafond, L.; Lam-Trong, T.; Landiech, P.; Lapeyrere, V.; Larqué, T.; Laudet, P.; Lautier, N.; Lecann, H.; Lefevre, L.; Leruyet, B.; Levacher, P.; Magnan, A.; Mazy, E.; Mertens, F.; Mesnager, J. -M.; Meunier, J. -C.; Michel, J. -P.; Monjoin, W.; Naudet, D.; Nguyen-Kim, K.; Orcesi, J. -L.; Ottacher, H.; Perez, R.; Peter, G.; Plasson, P.; Plesseria, J. -Y.; Pontet, B.; Pradines, A.; Quentin, C.; Reynaud, J. -L.; Rolland, G.; Rollenhagen, F.; Romagnan, R.; Russ, N.; Schmidt, R.; Schwartz, N.; Sebbag, I.; Sedes, G.; Smit, H.; Steller, M. B.; Sunter, W.; Surace, C.; Tello, M.; Tiphène, D.; Toulouse, P.; Ulmer, B.; Vandermarcq, O.; Vergnault, E.; Vuillemin, A.; Zanatta, P. Bibcode: 2009A&A...506..287L Altcode: 2009arXiv0908.0241L Aims: We report the discovery of very shallow (Δ F/F ≈ 3.4× 10-4), periodic dips in the light curve of an active V = 11.7 G9V star observed by the CoRoT satellite, which we interpret as caused by a transiting companion. We describe the 3-colour CoRoT data and complementary ground-based observations that support the planetary nature of the companion.
Methods: We used CoRoT colours information, good angular resolution ground-based photometric observations in- and out- of transit, adaptive optics imaging, near-infrared spectroscopy, and preliminary results from radial velocity measurements, to test the diluted eclipsing binary scenarios. The parameters of the host star were derived from optical spectra, which were then combined with the CoRoT light curve to derive parameters of the companion.
Results: We examined all conceivable cases of false positives carefully, and all the tests support the planetary hypothesis. Blends with separation >0.40´´or triple systems are almost excluded with a 8 × 10-4 risk left. We conclude that, inasmuch we have been exhaustive, we have discovered a planetary companion, named CoRoT-7b, for which we derive a period of 0.853 59 ± 3 × 10-5 day and a radius of Rp = 1.68 ± 0.09 R_Earth. Analysis of preliminary radial velocity data yields an upper limit of 21 M_Earth for the companion mass, supporting the finding.
Conclusions: CoRoT-7b is very likely the first Super-Earth with a measured radius. This object illustrates what will probably become a common situation with missions such as Kepler, namely the need to establish the planetary origin of transits in the absence of a firm radial velocity detection and mass measurement. The composition of CoRoT-7b remains loosely constrained without a precise mass. A very high surface temperature on its irradiated face, ≈1800-2600 K at the substellar point, and a very low one, ≈50 K, on its dark face assuming no atmosphere, have been derived.

The CoRoT space mission, launched on 27 December 2006, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA, Germany, and Spain. First CoRoT data are available to the public from the CoRoT archive: http://idoc-corot.ias.u-psud.fr. The complementary observations were obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT) which is operated by NRC in Canada, INSU-CNRS in France, and the University of Hawaii; ESO Telescopes at the La Silla and Paranal Observatories under programme ID 081.C-0413(C), DDT 282.C-5015; the IAC80 telescope operated by the Instituto de Astrofísica de Tenerife at the Observatorio del Teide; the Isaac Newton Telescope (INT), operated on the island of La Palma by the Isaac Newton group in the Spanish Observatorio del Roque de Los Muchachos of the Instituto de Astrofisica de Canarias; and at the Anglo-Australian Telescope that have been funded by the Optical Infrared Coordination network (OPTICON), a major international collaboration supported by the Research Infrastructures Programme of the European Commissions Sixth Framework Programme; Radial-velocity observations were obtained with the SOPHIE spectrograph at the 1.93m telescope of Observatoire de Haute Provence, France. Title: A Doppler Spectro-Imager dedicated to Jovian seismology and aeronomy onboard on Laplace/EJSM Jupiter Ganymede Orbiter Authors: Schmider, F. X.; Gaulme, P.; Appourchaux, T.; Guillot, T.; Mosser, B.; Rouesnel, F.; Sanchez-Lavega, A.; Tosi, F.; Mousis, O.; Eff-Darwich, A. Bibcode: 2009epsc.conf...82S Altcode: No abstract at ADS Title: Radius Determination of Solar-type Stars Using Asteroseismology: What to Expect from the Kepler Mission Authors: Stello, Dennis; Chaplin, William J.; Bruntt, Hans; Creevey, Orlagh L.; García-Hernández, Antonio; Monteiro, Mario J. P. F. G.; Moya, Andrés; Quirion, Pierre-Olivier; Sousa, Sergio G.; Suárez, Juan-Carlos; Appourchaux, Thierry; Arentoft, Torben; Ballot, Jerome; Bedding, Timothy R.; Christensen-Dalsgaard, Jørgen; Elsworth, Yvonne; Fletcher, Stephen T.; García, Rafael A.; Houdek, Günter; Jiménez-Reyes, Sebastian J.; Kjeldsen, Hans; New, Roger; Régulo, Clara; Salabert, David; Toutain, Thierry Bibcode: 2009ApJ...700.1589S Altcode: 2009arXiv0906.0766S For distant stars, as observed by the NASA Kepler satellite, parallax information is currently of fairly low quality and is not complete. This limits the precision with which the absolute sizes of the stars and their potential transiting planets can be determined by traditional methods. Asteroseismology will be used to aid the radius determination of stars observed during NASA's Kepler mission. We report on the recent asteroFLAG hare-and-hounds Exercise#2, where a group of "hares" simulated data of F-K main-sequence stars that a group of "hounds" sought to analyze, aimed at determining the stellar radii. We investigated stars in the range 9 < V < 15, both with and without parallaxes. We further test different uncertainties in T eff, and compare results with and without using asteroseismic constraints. Based on the asteroseismic large frequency spacing, obtained from simulations of 4 yr time series data from the Kepler mission, we demonstrate that the stellar radii can be correctly and precisely determined, when combined with traditional stellar parameters from the Kepler Input Catalogue. The radii found by the various methods used by each independent hound generally agree with the true values of the artificial stars to within 3%, when the large frequency spacing is used. This is 5-10 times better than the results where seismology is not applied. These results give strong confidence that radius estimation can be performed to better than 3% for solar-like stars using automatic pipeline reduction. Even when the stellar distance and luminosity are unknown we can obtain the same level of agreement. Given the uncertainties used for this exercise we find that the input log g and parallax do not help to constrain the radius, and that T eff and metallicity are the only parameters we need in addition to the large frequency spacing. It is the uncertainty in the metallicity that dominates the uncertainty in the radius. Title: SIAMOIS: asteroseismology in Antarctica Authors: Mosser, B.; Buey, T.; Catala, C.; Appourchaux, T.; Charpinet, S.; Mathias, Ph.; Maillard, J. P.; Siamois Team Bibcode: 2009CoAst.158..337M Altcode: SIAMOIS is a ground-based asteroseismology project, to pursue velocity measurements from the Dome C Concordia station in Antarctica. The scientific program of SIAMOIS is based on the very precise asteroseismic observation of nearby bright targets, focussing on the observations of solar-like oscillations in solar-like stars. Spectrometric observations with SIAMOIS will be able to detect l=3 oscillation modes that cannot be analyzed with space-borne photometric observations. The Doppler data, less affected by the stellar activity noise, will yield a more precise mode structure inversion, thus a high-precision determination of the stellar interior structure. The benefit of precise Doppler observations of nearby targets, with addition of interferometric and high-resolution spectrometric measurements, will allow us to investigate in detail the physical laws governing the stellar interior structure and evolution.

Dome C appears to be the ideal place for ground-based asteroseismic observations as it is capable of delivering a duty cycle as high as 90% during the three-month long polar night. This duty cycle, a crucial point for asteroseismology, is comparable to space-borne observations. The SIAMOIS concept is based on Fourier Transform interferometry, which leads to a small instrument designed and developed for the harsh conditions in Antarctica. The instrument will be fully automatic, with no moving parts, and it will require only a very simple initial set up in Antarctica. Title: Solar-Like Oscillations in a Massive Star Authors: Belkacem, Kévin; Samadi, Réza; Goupil, Marie-Jo; Lefèvre, Laure; Baudin, Fréderic; Deheuvels, Sébastien; Dupret, Marc-Antoine; Appourchaux, Thierry; Scuflaire, Richard; Auvergne, Michel; Catala, Claude; Michel, Eric; Miglio, Andrea; Montalban, Josefina; Thoul, Anne; Talon, Suzanne; Baglin, Annie; Noels, Arlette Bibcode: 2009Sci...324.1540B Altcode: 2009arXiv0906.3788B Seismology of stars provides insight into the physical mechanisms taking place in their interior, with modes of oscillation probing different layers. Low-amplitude acoustic oscillations excited by turbulent convection were detected four decades ago in the Sun and more recently in low-mass main-sequence stars. Using data gathered by the Convection Rotation and Planetary Transits mission, we report here on the detection of solar-like oscillations in a massive star, V1449 Aql, which is a known large-amplitude (β Cephei) pulsator. Title: Measurement of Low Signal-To-Noise Ratio Solar p-Modes in Spatially Resolved Helioseismic Data Authors: Salabert, D.; Leibacher, J.; Appourchaux, T.; Hill, F. Bibcode: 2009ApJ...696..653S Altcode: 2009arXiv0902.2561S We present an adaptation of the rotation-corrected, m-averaged spectrum technique designed to observe low signal-to-noise ratio (S/N), low-frequency solar p-modes. The frequency shift of each of the 2l + 1 m spectra of a given (n, l) multiplet is chosen that maximizes the likelihood of the m-averaged spectrum. A high S/N can result from combining individual low S/N, individual-m spectra, none of which would yield a strong enough peak to measure. We apply the technique to Global Oscillation Network Group and Michelson Doppler Imager data and show that it allows us to measure modes with lower frequencies than those obtained with classic peak-fitting analysis of the individual-m spectra. We measure their central frequencies, splittings, asymmetries, lifetimes, and amplitudes. The low frequency, low- and intermediate-angular degrees rendered accessible by this new method correspond to modes that are sensitive to the deep solar interior down to the core (l <= 3) and to the radiative interior (4 <= l <= 35). Moreover, the low-frequency modes have deeper upper turning points, and are thus less sensitive to the turbulence and magnetic fields of the outer layers, as well as uncertainties in the nature of the external boundary condition. As a result of their longer lifetimes (narrower linewidths) at the same S/N the determination of the frequencies of lower frequency modes is more accurate, and the resulting inversions should be more precise. Title: Intrinsic photometric characterisation of stellar oscillations and granulation. Solar reference values and CoRoT response functions Authors: Michel, E.; Samadi, R.; Baudin, F.; Barban, C.; Appourchaux, T.; Auvergne, M. Bibcode: 2009A&A...495..979M Altcode: 2008arXiv0809.1078M Context: Measuring amplitudes of solar-like oscillations and the granulation power spectral density constitute two promising sources of information to improve our understanding and description of the convection in outer layers of stars. However, different instruments, using different techniques and different bandpasses, give measurements that cannot be directly compared to each other or to theoretical values.
Aims: In this work, we define simple response functions to derive intrinsic oscillation amplitudes and granulation power densities, from photometry measurements obtained with a specific instrument on a specific star.
Methods: We test this method on different photometry data sets obtained on the Sun with two different instruments in three different bandpasses.
Results: We show that the results are in good agreement and we establish reference intrinsic values for the Sun with photometry. We also compute the response functions of the CoRoT instrument for a range of parameters representative of the Main Sequence solar-like pulsators to be observed with CoRoT. We show that these response functions can be conveniently described by simple analytic functions of the effective temperature of the target star. Title: POLAR investigation of the Sun—POLARIS Authors: Appourchaux, T.; Liewer, P.; Watt, M.; Alexander, D.; Andretta, V.; Auchère, F.; D'Arrigo, P.; Ayon, J.; Corbard, T.; Fineschi, S.; Finsterle, W.; Floyd, L.; Garbe, G.; Gizon, L.; Hassler, D.; Harra, L.; Kosovichev, A.; Leibacher, J.; Leipold, M.; Murphy, N.; Maksimovic, M.; Martinez-Pillet, V.; Matthews, B. S. A.; Mewaldt, R.; Moses, D.; Newmark, J.; Régnier, S.; Schmutz, W.; Socker, D.; Spadaro, D.; Stuttard, M.; Trosseille, C.; Ulrich, R.; Velli, M.; Vourlidas, A.; Wimmer-Schweingruber, C. R.; Zurbuchen, T. Bibcode: 2009ExA....23.1079A Altcode: 2008ExA...tmp...40A; 2008arXiv0805.4389A The POLAR Investigation of the Sun (POLARIS) mission uses a combination of a gravity assist and solar sail propulsion to place a spacecraft in a 0.48 AU circular orbit around the Sun with an inclination of 75° with respect to solar equator. This challenging orbit is made possible by the challenging development of solar sail propulsion. This first extended view of the high-latitude regions of the Sun will enable crucial observations not possible from the ecliptic viewpoint or from Solar Orbiter. While Solar Orbiter would give the first glimpse of the high latitude magnetic field and flows to probe the solar dynamo, it does not have sufficient viewing of the polar regions to achieve POLARIS’s primary objective: determining the relation between the magnetism and dynamics of the Sun’s polar regions and the solar cycle. Title: Astrodynamical Space Test of Relativity Using Optical Devices I (ASTROD I)—A class-M fundamental physics mission proposal for Cosmic Vision 2015-2025 Authors: Appourchaux, Thierry; Burston, Raymond; Chen, Yanbei; Cruise, Michael; Dittus, Hansjörg; Foulon, Bernard; Gill, Patrick; Gizon, Laurent; Klein, Hugh; Klioner, Sergei; Kopeikin, Sergei; Krüger, Hans; Lämmerzahl, Claus; Lobo, Alberto; Luo, Xinlian; Margolis, Helen; Ni, Wei-Tou; Patón, Antonio Pulido; Peng, Qiuhe; Peters, Achim; Rasel, Ernst; Rüdiger, Albrecht; Samain, Étienne; Selig, Hanns; Shaul, Diana; Sumner, Timothy; Theil, Stephan; Touboul, Pierre; Turyshev, Slava; Wang, Haitao; Wang, Li; Wen, Linqing; Wicht, Andreas; Wu, Ji; Zhang, Xiaomin; Zhao, Cheng Bibcode: 2009ExA....23..491A Altcode: 2008arXiv0802.0582A ASTROD I is a planned interplanetary space mission with multiple goals. The primary aims are: to test general relativity with an improvement in sensitivity of over three orders of magnitude, improving our understanding of gravity and aiding the development of a new quantum gravity theory; to measure key solar system parameters with increased accuracy, advancing solar physics and our knowledge of the solar system; and to measure the time rate of change of the gravitational constant with an order of magnitude improvement and the anomalous Pioneer acceleration, thereby probing dark matter and dark energy gravitationally. It is an international project, with major contributions from Europe and China and is envisaged as the first in a series of ASTROD missions. ASTROD I will consist of one spacecraft carrying a telescope, four lasers, two event timers and a clock. Two-way, two-wavelength laser pulse ranging will be used between the spacecraft in a solar orbit and deep space laser stations on Earth, to achieve the ASTROD I goals. A second mission, ASTROD (ASTROD II) is envisaged as a three-spacecraft mission which would test General Relativity to 1 ppb, enable detection of solar g-modes, measure the solar Lense-Thirring effect to 10 ppm, and probe gravitational waves at frequencies below the LISA bandwidth. In the third phase (ASTROD III or Super-ASTROD), larger orbits could be implemented to map the outer solar system and to probe primordial gravitational-waves at frequencies below the ASTROD II bandwidth. Title: First asteroseismic results from CoRoT Authors: Michel, E.; Baglin, A.; Weiss, W. W.; Auvergne, M.; Catala, C.; Aerts, C.; Appourchaux, T.; Barban, C.; Baudin, F.; Briquet, M. -L.; Carrier, F.; Debosher, J.; De Ridder, J.; Garcia, R. A.; Garrido, R.; Gutierrez, J.; Kallinger, T.; Lefevre, L.; Neiner, C.; Poretti, E.; Samadi, R.; Sarro, L.; COROT Team Bibcode: 2008CoAst.157...69M Altcode: About one year after the end of the first observational run and six months after the first CoRoT data delivery, we comment the data exploitation progress for different types of stars. We consider first results to illustrate how these data of unprecedented quality shed a new light on the field of stellar seismology. Title: Solar-like stars as seen by CoRoT Authors: Garcia, R. A.; Appourchaux, T.; Baglin, A.; Auvergne, M.; Barban, C.; Baudin, F.; Michel, E.; Mosser, B.; Samadi, R.; Data Analysis Team D. A. T Bibcode: 2008CoAst.157..288G Altcode: For more than a year, photometric high-quality data have been achieved from the CoRoT (COnvection ROtation and Planetary Transits; Baglin et al. 2006, Michel et al. 2008) min- isatellite developed by the French space agency (CNES) in collaboration with the Science Program of ESA, Austria, Belgium, Brazil Germany and Spain. The power spectrum of 4 dif- ferent solar-like stars (stars having sub-surface convective zones showing an acoustic (p) mode spectrum) has been obtained with unprecedented quality allowing the precise study of their seismic properties. These solar-like stars are F stars with masses in the range 1.0 to 1.4 M⊙ and are significantly hotter than the Sun. Title: First asteroseismic results from CoRoT Authors: Michel, E.; Baglin, A.; Weiss, W. W.; Auvergne, M.; Catala, C.; Aerts, C.; Appourchaux, T.; Barban, C.; Baudin, F.; Briquet, M.; Carrier, F.; Degroote, P.; De Ridder, J.; Garcia, R. A.; Garrido, R.; Gutiérrez-Soto, J.; Kallinger, T.; Lefevre, L.; Neiner, C.; Poretti, E.; Samadi, R.; Sarro, L.; Alecian, G.; Andrade, L.; Ballot, J.; Benomar, O.; Berthomieu, G.; Boumier, P.; Charpinet, S.; de Batz, B.; Deheuvels, S.; Dupret, M. -A.; Emilio, M.; Fabregat, J.; Facanha, W.; Floquet, M.; Frémat, Y.; Fridlund, M.; Goupil, M. -J.; Grotsch-Noels, A.; Handler, G.; Huat, A. -L.; Hubert, A. -M.; Janot-Pacheco, E.; Kjeldsen, H.; Lebreton, Y.; Leroy, B.; Martayan, C.; Mathias, P.; Miglio, A.; Montalban, J.; Monteiro, M. J. P. F. G.; Mosser, B.; Provost, J; Regulo, C.; Renan de Medeiros, J.; Ribas, I.; Roca Cortés, T.; Roxburgh, I.; Suso, J.; Thoul, A.; Toutain, T.; Tiphene, D.; Turck-Chieze, S.; Vauclair, S.; Vauclair, G.; Zwintz, K. Bibcode: 2008CoAst.156...73M Altcode: About one year after the end of the first observational run and six months after the first CoRoT data delivery, we comment the data exploitation progress for different types of stars. We consider first results to illustrate how these data of unprecedented quality shed a new light on the field of stellar seismology. Title: A Multisite Campaign to Measure Solar-like Oscillations in Procyon. I. Observations, Data Reduction, and Slow Variations Authors: Arentoft, Torben; Kjeldsen, Hans; Bedding, Timothy R.; Bazot, Michaël; Christensen-Dalsgaard, Jørgen; Dall, Thomas H.; Karoff, Christoffer; Carrier, Fabien; Eggenberger, Patrick; Sosnowska, Danuta; Wittenmyer, Robert A.; Endl, Michael; Metcalfe, Travis S.; Hekker, Saskia; Reffert, Sabine; Butler, R. Paul; Bruntt, Hans; Kiss, László L.; O'Toole, Simon J.; Kambe, Eiji; Ando, Hiroyasu; Izumiura, Hideyuki; Sato, Bun'ei; Hartmann, Michael; Hatzes, Artie; Bouchy, Francois; Mosser, Benoit; Appourchaux, Thierry; Barban, Caroline; Berthomieu, Gabrielle; Garcia, Rafael A.; Michel, Eric; Provost, Janine; Turck-Chièze, Sylvaine; Martić, Milena; Lebrun, Jean-Claude; Schmitt, Jerome; Bertaux, Jean-Loup; Bonanno, Alfio; Benatti, Serena; Claudi, Riccardo U.; Cosentino, Rosario; Leccia, Silvio; Frandsen, Søren; Brogaard, Karsten; Glowienka, Lars; Grundahl, Frank; Stempels, Eric Bibcode: 2008ApJ...687.1180A Altcode: 2008arXiv0807.3794A We have carried out a multisite campaign to measure oscillations in the F5 star Procyon A. We obtained high-precision velocity observations over more than three weeks with 11 telescopes, with almost continuous coverage for the central 10 days. This represents the most extensive campaign so far organized on any solar-type oscillator. We describe in detail the methods we used for processing and combining the data. These involved calculating weights for the velocity time series from the measurement uncertainties and adjusting them in order to minimize the noise level of the combined data. The time series of velocities for Procyon shows the clear signature of oscillations, with a plateau of excess power that is centered at 0.9 mHz and is broader than has been seen for other stars. The mean amplitude of the radial modes is 38.1 +/- 1.3 cm s-1 (2.0 times solar), which is consistent with previous detections from the ground and by the WIRE spacecraft, and also with the upper limit set by the MOST spacecraft. The variation of the amplitude during the observing campaign allows us to estimate the mode lifetime to be 1.5+ 1.9-0.8 days. We also find a slow variation in the radial velocity of Procyon, with good agreement between different telescopes. These variations are remarkably similar to those seen in the Sun, and we interpret them as being due to rotational modulation from active regions on the stellar surface. The variations appear to have a period of about 10 days, which presumably equals the stellar rotation period or, perhaps, half of it. The amount of power in these slow variations indicates that the fractional area of Procyon covered by active regions is slightly higher than for the Sun. Title: SIAMOIS: Seismic Interferometer to Measure Oscillations in the Interior of Stars Authors: Mosser, Benoit; Appourchaux, Thierry; Catala, Claude; Buey, Jean-Tristan; SIAMOIS Team Bibcode: 2008JPhCS.118a2042M Altcode: SIAMOIS is a project devoted to ground-based asteroseismology, involving an instrument to be installed at the Dome C Concordia station in Antarctica. SIAMOIS provides an asteroseismic programme that can follow the way currently opened by the space project CoRoT, with unique information on G and K type bright stars on the main sequence. In addition, spectrometric observations with SIAMOIS will be able to detect oscillation modes that cannot be analyzed in photometry: the Doppler data, less affected by the stellar activity noise, yield a more precise mode structure inversion. The SIAMOIS concept is based on Fourier Transform interferometry. Such a principle leads to a small instrument designed and developed for the harsh conditions in Antarctic. The instrument will be fully automatic, with no moving parts, and a very simple initial set up in Antarctic. The dedicated scientific programme will avoid the complications related to a versatile instrument. Data reduction will be performed in real time, and the transfer of the asteroseismic data to Europe will require only a modest bandwidth. SIAMOIS will observe with a dedicated small 40-cm telescope. Dome C appears to be the ideal place for ground-based asteroseismic observations. The unequalled weather conditions yield a duty cycle as high as 90% over 3 months, as was observed during the 2005 wintering. This high duty cycle, a crucial point for asteroseismology, is comparable to the best space-based observations. Long time series (up to 3 months) will be possible, thanks to the long duration of the polar night. SIAMOIS can be seen as one of the very first observational projects in astronomy at Dome C. Its scientific programme will take full advantage of the unique quality of this site, and will constitute a necessary first step in preparation of future more ambitious programmes requiring more sophisticated instrumentation and larger collectors. Title: Oscillations in Procyon A: First results from a multi-site campaign Authors: Hekker, S.; Arentoft, T.; Kjeldsen, H.; Bedding, T. R.; Christensen-Dalsgaard, J.; Reffert, S.; Bruntt, H.; Butler, R. P.; Kiss, L. L.; O'Toole, S. J.; Kambe, E.; Ando, H.; Izumiura, H.; Sato, B.; Hartmann, M.; Hatzes, A. P.; Appourchaux, T.; Barban, C.; Berthomieu, G.; Bouchy, F.; García, R. A.; Lebrun, J. -C.; Martić, M.; Michel, E.; Mosser, B.; Nghiem, P. A. P.; Provost, J.; Samadi, R.; Thévenin, F.; Turck-Chièze, S.; Bonanno, S. A.; Benatti, S.; Claudi, R. U.; Cosentino, R.; Leccia, S.; Frandsen, S.; Brogaard, K.; Grundahl, F.; Stempels, H. C.; Bazot, M.; Dall, T. H.; Karoff, C.; Carrier, F.; Eggenberger, P.; Sosnowska, D.; Wittenmyer, R. A.; Endl, M.; Metcalfe, T. S. Bibcode: 2008JPhCS.118a2059H Altcode: 2007arXiv0710.3772H Procyon A is a bright F5IV star in a binary system. Although the distance, mass and angular diameter of this star are all known with high precision, the exact evolutionary state is still unclear. Evolutionary tracks with different ages and different mass fractions of hydrogen in the core pass, within the errors, through the observed position of Procyon A in the Hertzsprung-Russell diagram. For more than15 years several different groups have studied the solar-like oscillations in Procyon A to determine its evolutionary state. Although several studies independently detected power excess in the periodogram, there is no agreement on the actual oscillation frequencies yet. This is probably due to either insufficient high-quality data (i.e., aliasing) or due to intrinsic properties of the star (i.e., short mode lifetimes). Now a spectroscopic multi-site campaign using 10 telescopes world-wide (minimizing aliasing effects) with a total time span of nearly 4 weeks (increase the frequency resolution) is performed to identify frequencies in this star and finally determine its properties and evolutionary state. Title: Detecting solar g modes with ASTROD Authors: Burston, R.; Gizon, L.; Appourchaux, T.; Ni, W. -T.; ASTROD I ESA cosmic vision 2015-2025 Team Bibcode: 2008JPhCS.118a2043B Altcode: 2008arXiv0802.1614B We present an up-to-date estimate for the prospect of using the Astrodynamical Space Test of Relativity using Optical Devices (ASTROD) [1, 2, 3, 4] for an unambiguous detection of solar g modes (f < 400 μHz) through their gravitational signature. There are currently two major efforts to detect low-frequency gravitational effects, ASTROD and the Laser Interferometer Space Antenna (LISA) [5]. Using the most recent g mode surface amplitude estimates, both observational and theoretical, it is unclear whether LISA will be capable of successfully detecting these modes. The ASTROD project may be better suited for detection as its sensitivity curve is shifted towards lower frequencies with the best sensitivity occurring in the range 100 - 300 μHz. Title: CoRoT Measures Solar-Like Oscillations and Granulation in Stars Hotter Than the Sun Authors: Michel, Eric; Baglin, Annie; Auvergne, Michel; Catala, Claude; Samadi, Reza; Baudin, Frédéric; Appourchaux, Thierry; Barban, Caroline; Weiss, Werner W.; Berthomieu, Gabrielle; Boumier, Patrick; Dupret, Marc-Antoine; Garcia, Rafael A.; Fridlund, Malcolm; Garrido, Rafael; Goupil, Marie-Jo; Kjeldsen, Hans; Lebreton, Yveline; Mosser, Benoît; Grotsch-Noels, Arlette; Janot-Pacheco, Eduardo; Provost, Janine; Roxburgh, Ian W.; Thoul, Anne; Toutain, Thierry; Tiphène, Didier; Turck-Chieze, Sylvaine; Vauclair, Sylvie D.; Vauclair, Gérard P.; Aerts, Conny; Alecian, Georges; Ballot, Jérôme; Charpinet, Stéphane; Hubert, Anne-Marie; Lignières, François; Mathias, Philippe; Monteiro, Mario J. P. F. G.; Neiner, Coralie; Poretti, Ennio; Renan de Medeiros, José; Ribas, Ignasi; Rieutord, Michel L.; Roca Cortés, Teodoro; Zwintz, Konstanze Bibcode: 2008Sci...322..558M Altcode: 2008arXiv0812.1267M Oscillations of the Sun have been used to understand its interior structure. The extension of similar studies to more distant stars has raised many difficulties despite the strong efforts of the international community over the past decades. The CoRoT (Convection Rotation and Planetary Transits) satellite, launched in December 2006, has now measured oscillations and the stellar granulation signature in three main sequence stars that are noticeably hotter than the sun. The oscillation amplitudes are about 1.5 times as large as those in the Sun; the stellar granulation is up to three times as high. The stellar amplitudes are about 25% below the theoretic values, providing a measurement of the nonadiabaticity of the process ruling the oscillations in the outer layers of the stars. Title: solarFLAG hare and hounds: estimation of p-mode frequencies from Sun-as-star helioseismology data Authors: Jiménez-Reyes, S. J.; Chaplin, W. J.; García, R. A.; Appourchaux, T.; Baudin, F.; Boumier, P.; Elsworth, Y.; Fletcher, S. T.; Lazrek, M.; Leibacher, J. W.; Lochard, J.; New, R.; Régulo, C.; Salabert, D.; Toutain, T.; Verner, G. A.; Wachter, R. Bibcode: 2008MNRAS.389.1780J Altcode: 2008arXiv0807.0989J; 2008MNRAS.tmp..954J; 2008MNRAS.tmp.1026J We report on the results of the latest solarFLAG hare-and-hounds exercise, which was concerned with testing methods for extraction of frequencies of low-degree solar p modes from data collected by Sun-as-a-star observations. We have used the new solarFLAG simulator, which includes the effects of correlated mode excitation and correlations with background noise, to make artificial time-series data that mimic Doppler velocity observations of the Sun-as-a-star. The correlations give rise to asymmetry of mode peaks in the frequency power spectrum. 10 members of the group (the hounds) applied their `peak-bagging' codes to a 3456-d data set, and the estimated mode frequencies were returned to the hare (who was WJC) for comparison. Analysis of the results reveals a systematic bias in the estimated frequencies of modes above ~1.8mHz. The bias is negative, meaning the estimated frequencies systematically underestimate the input frequencies.

We identify two sources that are the dominant contributions to the frequency bias. Both sources involve failure to model accurately subtle aspects of the observed power spectral density in the part (window) of the frequency power spectrum that is being fitted. One source of bias arises from a failure to account for the power spectral density coming from all those modes whose frequencies lie outside the fitting windows. The other source arises from a failure to account for the power spectral density of the weak l = 4 and 5 modes, which are often ignored in Sun-as-a-star analysis. The Sun-as-a-star peak-bagging codes need to allow for both sources, otherwise the frequencies are likely to be biased. Title: AsteroFLAG — from the Sun to the stars Authors: Chaplin, W. J.; Appourchaux, T.; Arentoft, T.; Ballot, J.; Baudin, F.; Bazot, M.; Bedding, T. R.; Christensen-Dalsgaard, J.; Creevey, O. L.; Duez, V.; Elsworth, Y.; Fletcher, S. T.; García, R. A.; Gough, D. O.; Jiménez, A.; Jiménez-Reyes, S. J.; Houdek, G.; Kjeldsen, H.; Lazrek, M.; Leibacher, J. W.; Monteiro, M. J. P. F. G.; Neiner, C.; New, R.; Régulo, C.; Salabert, D.; Samadi, R.; Sekii, T.; Sousa, S. G.; Toutain, T.; Turck-Chièze, S. Bibcode: 2008JPhCS.118a2048C Altcode: We stand on the threshold of a critical expansion of asteroseismology of Sun-like stars, the study of stellar interiors by observation and analysis of their global acoustic modes of oscillation. The Sun-like oscillations give a very rich spectrum allowing the internal structure and dynamics to be probed down into the stellar cores to very high precision. Asteroseismic observations of many stars will allow multiple-point tests of crucial aspects of stellar evolution and dynamo theory. The aims of the asteroFLAG collaboration are to help the community to refine existing, and to develop new, methods for analysis of the asteroseismic data on the Sun-like oscillators. Title: Development of a new analysis technique to measure low radial-order p modes in spatially-resolved helioseismic data Authors: Salabert, David; Leibacher, John W.; Appourchaux, Thierry Bibcode: 2008JPhCS.118a2086S Altcode: 2007arXiv0711.2825S In order to take full advantage of the long time series collected by the GONG and MDI helioseismic projects, we present here an adaptation of the rotation-corrected m-averaged spectrum technique in order to observe low radial-order solar p modes. Modeled profiles of the solar rotation demonstrated the potential advantage of such a technique [1, 2, 3]. Here we develop a new analysis procedure which finds the best estimates of the shift of each m of a given (n, ι) multiplet, commonly expressed as an expansion in a set of orthogonal polynomials, which yield the narrowest mode in the m-averaged spectrum. We apply the technique to the GONG data for modes with 1 <= ι <= 25 and show that it allows us to measure lower-frequency modes than with classic peak-fitting analysis of the individual-m spectra. Title: CoRoT sounds the stars: p-mode parameters of Sun-like oscillations on HD 49933 Authors: Appourchaux, T.; Michel, E.; Auvergne, M.; Baglin, A.; Toutain, T.; Baudin, F.; Benomar, O.; Chaplin, W. J.; Deheuvels, S.; Samadi, R.; Verner, G. A.; Boumier, P.; García, R. A.; Mosser, B.; Hulot, J. -C.; Ballot, J.; Barban, C.; Elsworth, Y.; Jiménez-Reyes, S. J.; Kjeldsen, H.; Régulo, C.; Roxburgh, I. W. Bibcode: 2008A&A...488..705A Altcode: Context: The first asteroseismology results from CoRoT are presented, on a star showing Sun-like oscillations. We have analyzed a 60 day lightcurve of high-quality photometric data collected by CoRoT on the F5 V star HD 49933. The data reveal a rich spectrum of overtones of low-degree p modes.
Aims: Our aim was to extract robust estimates of the key parameters of the p modes observed in the power spectrum of the lightcurve.
Methods: Estimation of the mode parameters was performed using maximum likelihood estimation of the power spectrum. A global fitting strategy was adopted whereby 15 mode orders of the mode spectrum (45 modes) were fitted simultaneously.
Results: The parameter estimates that we list include mode frequencies, peak linewidths, mode amplitudes, and a mean rotational frequency splitting. We find that the average large frequency (overtone) spacing derived from the fitted mode frequencies is 85.9 ± 0.15 μHz. The frequency of maximum amplitude of the radial modes is at 1760 μHz, where the observed rms mode amplitude is 3.75 ± 0.23 ppm. The mean rotational splitting of the non-radial modes appears to be in the range ≈2.7 μHz to ≈3.4 μHz. The angle of inclination offered by the star, as determined by fits to the amplitude ratios of the modes, appears to be in the range ≈50 degrees to ≈62 degrees.

The CoRoT space mission, launched on

2006 December 27, was developed and is operated by the CNES, with

participation of the Science Programs of ESA, ESA's RSSD, Austria,

Belgium, Brazil, Germany and Spain. Title: On deriving p-mode parameters for inclined solar-like stars Authors: Ballot, J.; Appourchaux, T.; Toutain, T.; Guittet, M. Bibcode: 2008A&A...486..867B Altcode: 2008arXiv0803.0885B Context: Thanks to their high quality, new and upcoming asteroseismic observations, with CoRoT, Kepler, and from the ground, benefit from experience gained with helioseismology.
Aims: We focus, in this paper, on solar-like oscillations, for which the inclination of the rotation axis is unknown. We present a theoretical study of the errors of p-mode parameters determined by means of a maximum-likelihood estimator, and we also analyze correlations and biases.
Methods: We used different, complementary approaches: we performed either semi-analytical computation of the Hessian matrix, fitting of single mean profiles, or Monte Carlo simulations.
Results: First, we give analytical approximations for the errors of frequency, inclination and rotational splitting. The determination of the inclination is very challenging for the common case of slow rotators (like the Sun), making the determination of a reliable rotational splitting difficult. Moreover, due to the numerous correlations, biases - more or less significant - can appear in the determination of various parameters in the case of bad inclination fittings, especially when a locking at 90° occurs. We also discuss this issue. Nevertheless, the central frequency and some derived parameters, such as the total power of the mode, are free of such biases. Title: Challenges for asteroseismic analysis of Sun-like stars Authors: Chaplin, W. J.; Houdek, G.; Appourchaux, T.; Elsworth, Y.; New, R.; Toutain, T. Bibcode: 2008A&A...485..813C Altcode: 2008arXiv0804.4371C Context: Asteroseismology of Sun-like stars is undergoing rapid expansion with, for example, new data from the CoRoT mission and continuation of ground-based campaigns. There is also the exciting upcoming prospect of NASA's Kepler mission, which will allow the asteroseismic study of several hundred Sun-like targets, in some cases for periods lasting up to a few years.
Aims: The seismic mode parameters are the input data needed for making inference on stars and their internal structures. In this paper we discuss the ease with which it will be possible to extract estimates of individual mode parameters, dependent on the mass, age, and visual brightness of the star. Our results are generally applicable; however, we look at mode detectability in the context of the upcoming Kepler observations.
Methods: To inform our discussions we make predictions of various seismic parameters. To do this we use simple empirical scaling relations and detailed pulsation computations of the stochastic excitation and damping characteristics of the Sun-like p modes.
Results: The issues related to parameter extraction on individual p modes discussed here are mode detectability, the detectability and impact of stellar activity cycles, and the ability to measure properties of rotationally split components, which is dependent on the relative importance of the rotational characteristics of the star and the damping of the stochastically excited p modes. Title: Design of a Fabry-Perot interferometer for the SO/PHI instrument on Solar Orbiter Authors: Trosseille, Clément; Appourchaux, Thierry; Fourmond, Jean-Jacques Bibcode: 2008SPIE.7010E..17T Altcode: 2008SPIE.7010E..37T We present our work on the spectral analyser of the Polarimetric and Helioseismic Imager (PHI) instrument to be flown aboard ESA's Solar Orbiter mission. We detail the choices that were made to determine the concept of the spectral analyser, a Lithium Niobate Fabry-Perot interferometer, and its characteristics, as to fulfil both scientific needs and technical requirements. We will present the first experimental results - including stability, repeatability, parallelism, spectral homogeneity and imaging capability - on an air-spaced piezoelectric-tunable etalon, which is the backup solution for PHI. Title: Effect of the stellar inclination angle upon theoretical errors of l=1 p-mode parameters Authors: Ballot, J.; Appourchaux, T.; Toutain, T. Bibcode: 2008AN....329..558B Altcode: The asteroseismic observations provided by current and future missions like CoRoT or Kepler will have a quality closer to those obtained for the Sun. In this context, tools and methods developed for helioseismology can be applied to other stars. In this paper, we focus on solar-like oscillations of stars with an unknown rotation axis inclination and study, by means of maximum-likelihood estimation, the errors on the determination of l=1 p-mode parameters. Title: AsteroFLAG: First results from hare-and-hounds Exercise #1 Authors: Chaplin, W. J.; Appourchaux, T.; Arentoft, T.; Ballot, J.; Christensen-Dalsgaard, J.; Creevey, O. L.; Elsworth, Y.; Fletcher, S. T.; García, R. A.; Houdek, G.; Jiménez-Reyes, S. J.; Kjeldsen, H.; New, R.; Régulo, C.; Salabert, D.; Sekii, T.; Sousa, S. G.; Toutain, T.; rest of asteroFLAG Group Bibcode: 2008AN....329..549C Altcode: 2008arXiv0803.4143C We report on initial results from the first phase of Exercise #1 of the asteroFLAG hare and hounds. The asteroFLAG group is helping to prepare for the asteroseismology component of NASA's Kepler mission, and the first phase of Exercise #1 is concerned with testing extraction of estimates of the large and small frequency spacings of the low-degree p modes from Kepler-like artificial data. These seismic frequency spacings will provide key input for complementing the exoplanet search data. Title: Helioseismology program for the PICARD satellite Authors: Corbard, T.; Boumier, P.; Appourchaux, T.; Jiménez-Reyes, S. J.; Gelly, B.; PICARD Team Bibcode: 2008AN....329..508C Altcode: The PICARD mission is a CNES micro-satellite to be launched in 2009. Its goal is to better understand the Sun and the potential impact of its activity on earth climate by measuring simultaneously the solar total and spectral irradiance, diameter, shape and oscillations. We present the scientific objectives, instrumental requirements and data products of the helioseismology program of PICARD which aims to observe the low to medium l p-mode oscillations in intensity and search for g-mode oscillation signatures at the limb.

http://www.picard-mission.cnes.fr Title: Bayesian approach for g-mode detection, or how to restrict our imagination Authors: Appourchaux, T. Bibcode: 2008AN....329..485A Altcode: 2007arXiv0711.0435A Nowadays, g-mode detection is based upon a priori theoretical knowledge. By doing so, detection becomes more restricted to what we can imagine. De facto, the universe of possibilities is made narrower. Such an approach is pertinent for Bayesian statisticians. Examples of how Bayesian inferences can be applied to spectral analysis and helioseismic power spectra are given. Our intention is not to give the full statistical framework (much too ambitious) but to provide an appetizer for going further in the direction of a proper Bayesian inference, especially for detecting gravity modes. Title: Low-Frequency Solar p Modes in GONG and MDI Observations using m-Averaged Spectra Authors: Leibacher, J.; Salabert, D.; Appourchaux, T.; Hill, F. Bibcode: 2008AGUSMSP41A..06L Altcode: The GONG and MDI global helioseismology pipelines provide solar acoustic mode parameters for 108- and 72-day time series respectively by fitting the 2 ℓ + 1 individual-m spectra of a given (n, ℓ/) multiplet either individually (GONG) or simultaneously (MDI). Our knowledge of the variable solar interior through helioseismic observations derives primarily from these two analysis pipelines. We have developed a new method to extract the mode parameters by adjusting the rotation- and structure-induced frequency shift for each m-spectrum to minimize the mode width in the m-averaged spectrum. The m-averaged spectrum appears to be a powerful tool for low signal-to-noise-ratio modes in the low-frequency range where the modes have very long lifetimes. Indeed, in the case of spatially-resolved helioseismic data (MDI, GONG, HMI), for a given multiplet (n, ℓ/), there exist 2 ℓ + 1 individual-m spectra, which can result in an average spectrum with a SNR ≫ 1 even when the individual-m spectra have a SNR < 1. We show here that the m-averaged spectrum technique, applied to the GONG 108-day and MDI 72-day time series, gives us access to a whole new range of predicted, low-SNR modes that had not been successfully fitted by the current MDI and GONG peak-fitting pipelines. We show that the modes that are measured by both techniques are extracted without bias. We apply this technique to 360-, 720-, 1080-, and 1440-day long GONG time series to infer the variability of the mode parameters with solar activity in the low-frequency range below ~ 1500 μHz. Title: Searching for p-modes in MOST Procyon data: another view Authors: Baudin, F.; Appourchaux, T.; Boumier, P.; Kuschnig, R.; Leibacher, J. W.; Matthews, J. M. Bibcode: 2008A&A...478..461B Altcode: 2007arXiv0711.0601B Context: Photometry of Procyon obtained by the MOST satellite in 2004 has been searched for p modes by several groups, with sometimes contradictory interpretations.
Aims: We explore two possible factors that complicate the analysis and may lead to erroneous reports of p modes in these data.
Methods: Two methods are used to illustrate the role of subtle instrumental effects in the photometry: time-frequency analysis, and a search for regularly spaced peaks in a Fourier spectrum based on the echelle diagramme approach.
Results: We find no convincing evidence of a p-mode signal in the MOST Procyon data. We can account for an apparent excess of power close to the p-mode frequency range and signs of structure in an echelle diagramme in terms of instrumental effects.

Based on data from the MOST satellite, a Canadian Space Agency mission, jointly operated by Dynacon Inc., the University of Toronto Institute for Aerospace Studies and the University of British Columbia, with the assistance of the University of Vienna. Title: Asteroseismology of Procyon with SOPHIE Authors: Mosser, B.; Bouchy, F.; Martić, M.; Appourchaux, T.; Barban, C.; Berthomieu, G.; Garcia, R. A.; Lebrun, J. C.; Michel, E.; Provost, J.; Thévenin, F.; Turck-Chièze, S. Bibcode: 2008A&A...478..197M Altcode: 2007arXiv0712.1368M Context: This paper reports a 9-night asteroseismic observation program conducted in January 2007 with the new spectrometer sophie at the OHP 193-cm telescope, on the F5 IV-V target Procyon A.
Aims: This first asteroseismic program with sophie was intended to test the performance of the instrument with a bright but demanding asteroseismic target and was part of a multisite network.
Methods: The sophie spectra have been reduced with the data reduction software provided by OHP. The Procyon asteroseismic data were then analyzed with statistical tools. The asymptotic analysis has been conducted considering possible curvature in the échelle diagram analysis.
Results: These observations have proven the efficient performance of sophie used as an asteroseismometer, and succeed in a clear detection of the large spacing. An échelle diagram based on the 54-μHz spacing shows clear ridges. Identification of the peaks exhibits large spacings varying from about 52 μHz to 56 μHz. Outside the frequency range [0.9, 1.0 mHz] where the identification is confused, the large spacing increases at a rate of about dΔν/dn ≃ 0.2 μHz. This may explain some of the different values of the large spacing obtained by previous observations.

Based on observations collected with the sophie échelle spectrometer mounted on the 1.93-m telescope at OHP, France (program 06B.PNPS.BOU); http://www.obs-hp.fr/www/guide/ sophie/sophie-eng.html Table of radial velocity measurements is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/478/197 Title: VizieR Online Data Catalog: Procyon (alpha CMi) radial velocities (Mosser+, 2008) Authors: Mosser, B.; Bouchy, F.; Martic, M.; Appourchaux, T.; Barban, C.; Berthomieu, G.; Garcia, R. A.; Lebrun, J. C.; Michel, E.; Provost, J.; Thevenin, F.; Turck-Chieze, S. Bibcode: 2007yCat..34780197M Altcode: Time series of the radial velocities of Procyon recorder with the echelle spectrometer SOPHIE at Observatoire de Haute Provence in January 2007.

(1 data file). Title: Simu-LC : a Light-Curve simulator for CoRoT Authors: Baudin, F.; Samadi, R.; Appourchaux, T.; Michel, E. Bibcode: 2007arXiv0710.3378B Altcode: Simulating the data that a space instrument like COROT will provide might look presomptuous. Indeed, it is certainly, when comparing to previous comparable instruments like IPHIR or GOLF. These two examples show that the nominal behaviour of the instrument is not always reached, but this does not prevent this instrument to provide very interesting data. However, despite some technical problems, IPHIR and GOLF yielded a wealth of scientific results. Thus, what is the interest of simulating COROT data? How close to reality these simualtions will get? This might not be the most important fact as the preparation of these simulations will help us to prepare the analysis of real data and to be ready in case of unexpected technical behaviour of the instrument perturbating the data, or unexpected physical behaviour of the targets of the instrument. A consequence of that is that the simulation tool must include technical and physical aspects, making the task even more difficult. These aspects cover: photon noise, p modes excitation, granulation signal, stellar activity signal, orbital perturbations, stellar rotation... The software presented here is freely available at: http://www.lesia.obspm.fr/~corotswg/simulightcurve.html Title: Needles in haystacks: how to use contemporaneous data in the search for low-frequency modes of oscillation of the Sun Authors: Broomhall, A. M.; Chaplin, W. J.; Elsworth, Y.; Appourchaux, T. Bibcode: 2007MNRAS.379....2B Altcode: 2007MNRAS.tmp..525B We show how to take advantage of contemporaneous data from two different instruments in the search for low-frequency modes of oscillation of the Sun. Contemporaneous data allow searches to be made for prominent, sharp concentrations of power which are coincident in frequency. Crucial to determining objective measures of the joint probability of the random occurrence of such features, which are potential candidates for modes, is a good understanding of the characteristics of the background noise. In this paper we show how to make proper allowance, in the calculation of the probability, for noise that is common to data from different instruments. This common noise is solar in origin, and comes from the solar granulation. Its presence makes calculation of the probability a non-trivial problem. We demonstrate application of the technique in searches for low-frequency p modes. The data we searched comprised 3071 d of contemporaneous Sun-as-a-star Doppler velocity observations made by the ground-based Birmingham Solar-Oscillations Network (BiSON), and the GOLF instrument onboard the ESA/NASA SOHO spacecraft. Title: On understanding the meaning of l = 2 and 3 p-mode frequencies as measured by various helioseismic instruments Authors: Appourchaux, T.; Chaplin, W. J. Bibcode: 2007A&A...469.1151A Altcode: Aims:Frequencies of the low-degree p-mode oscillations of the Sun may be extracted either from data collected by instruments that make full-disc observations of the Sun as a star, or from data collected by instruments that resolve, or image, the Sun's surface onto many detector elements. The two methods can show marked differences in their sensitivity to modes having certain combinations of degree and azimuthal order. These different sensitivities lead to differences in measurements of the central frequencies of the modes, which must be properly accounted for if data from two different instruments are to be compared, or combined.
Methods: We perform an analytical derivation of the p-mode frequency offsets expected between contemporaneous Sun-as-a-star and resolved-Sun data.
Results: Here, we demonstrate that the empirical factors derived by Chaplin et al. (2004, A&A, 424, 713) are reproduced by our analysis, but with a more marked dependence upon the mode linewidth. Title: Rotation Of The Deep Solar Interior From A Solar Cycle Of Gong Data Authors: Leibacher, John W.; Salabert, D.; Appourchaux, T.; Hill, F.; Howe, R. Bibcode: 2007AAS...210.2219L Altcode: 2007BAAS...39..127L We use 3960 days of Global Oscillation Network Group (GONG) data to derive the rotation of the deep solar interior. We obtain the splitting of low signal-to-noise multiplets - at low radial order and low spherical harmonic degree - using the m-averaged spectra - a technique that works well even when none of the individual-m spectra are clean enough to be fit. Central frequencies and rotational splittings are estimated down to l = 1 and 1 mHz. We illustrate here the validity of our method and infer the radial rotation profile down to 0.2 solar radius.

This work utilizes data obtained by the Global Oscillation Network Group (GONG) program, managed by the National Solar Observatory, which is operated by AURA, Inc. under a cooperative agreement with the National Science Foundation. The data were acquired by instruments operated by the Big Bear Solar Observatory, High Altitude Observatory, Learmonth Solar Observatory, Udaipur Solar Observatory, Instituto de Astrofisica de Canarias, and Cerro Tololo Interamerican Observatory. Title: On cross-spectrum capabilities for detecting stellar oscillation modes Authors: Appourchaux, T.; Leibacher, J.; Boumier, P. Bibcode: 2007A&A...463.1211A Altcode: Aims:Long-lived stellar oscillation modes are usually detected using Fourier transforms of time series of stellar radial velocities or brightness. It is commonly thought that one could use the cross spectrum of the two signals, or alternatively use the interleaved series of a single signal, to considerably improve the detection level by reducing the noise level.
Methods: We use a statistical analysis of the cross spectrum to compute its mean value and rms value, and use the associated signal-to-noise ratio for stochastically excited modes.
Results: Here, we demonstrate that the gain in the signal-to-noise ratio can indeed be improved for modes with a shorter lifetime than the observation time, but not those with a longer lifetime than the observation time. Title: EUI, The Ultraviolet Imaging Telescopes Of Solar Orbiter Authors: Hochedez, J. -F.; Appourchaux, T.; Defise, J. -M.; Harra, L. K.; Schühle, U.; Auchère, F.; Curdt, W.; Hancock, B.; Kretzschmar, M.; Lawrence, G.; Leclec'h, J. -C.; Marsch, E.; Mercier, R.; Parenti, S.; Podladchikova, E.; Ravet, M. -F.; Rochus, P.; Rodriguez, L.; Rouesnel, F.; Solanki, S.; Teriaca, L.; Van Driel, L.; Vial, J. -C.; Winter, B.; Zhukov, A. Bibcode: 2007ESASP.641E..33H Altcode: The scientific objectives of Solar Orbiter rely ubiquitously on EUI, its suite of solar atmosphere imaging telescopes. In the configuration discussed here, EUI includes three co-aligned High Resolution Imagers (HRI) and one Full Sun Imager (FSI). FSI and two HRIs observe in extreme ultraviolet passbands, dominated by coronal emission. Another HRI is designed for the hydrogen Lyman α radiation in the far UV, imaging the Chromosphere and the lower Transition Region. The current EUI design and some of its development challenges are highlighted. EUI profits from co-rotation phases, solar proximity and departure from the ecliptic. In synergy with the other S.O. payload, EUI probes the dynamics of the solar atmosphere, provides context data for all investigations and helps to link in-situ and remote-sensing observations. In short, it serves all four top-level goals of the mission. For these reasons, the EUI suite is keenly anticipated in the European scientific community and beyond. Title: Design Of A Fabry Perot Interferometer For The VIM Instrument Aboard Solar Orbiter Authors: Trosseille, C.; Appourchaux, T.; Martinez Pillet, V. Bibcode: 2007ESASP.641E..85T Altcode: The spectral analyser of the Visible light Imager and Magnetograph (VIM) is a critical device whose concept is dependent on scientific requirements and technical trade-offs, which are directly driven by the nature of the mission. Here, we report on the choices that were made to fulfill the scientific needs, while constantly keeping an eye on feasibility. We also list the critical points and remaining issues that should be investigated and addressed properly in further work. Title: Evaluation of the Scientific Performances for the Seismology Programme Authors: Appourchaux, T.; Berthomieu, G.; Michel, E.; Ballot, J.; Barban, C.; Baudin, F.; Boumier, P.; De Ridder, J.; Floquet, M.; Garcia, R. A.; Garrido, R.; Goupil, M. -J.; Lambert, P.; Lochard, J.; Mazumdar, A.; Neiner, C.; Poretti, E.; Provost, J.; Roxburgh, I.; Samadi, R.; Toutain, T. Bibcode: 2006ESASP1306..429A Altcode: The Data Analysis Team of the Seismology Working Group of COROT performed several hare-and-hound exercises. These exercises aimed at putting the team in a situation as if they would analyze data coming out of the COROT spacecraft. In total the team performed five different exercises simulating solar-like stars (HH#1, HH#2, HH#3), classical pulsators (HH#5), validating seismic calibration of stellar model (HH#2, HH#3) and pushing the limit of detection (HH#4). This paper tries both to serve as a summary and as a portal to other publications of the DAT. Title: Data Analysis Tools for the Seismology Programme Authors: Appourchaux, T.; Berthomieu, G.; Michel, E.; Aerts, C.; Ballot, J.; Barban, C.; Baudin, F.; Boumier, P.; De Ridder, J.; Floquet, M.; Garcia, R. A.; Garrido, R.; Goupil, M. -J.; Lambert, P.; Lochard, J.; Neiner, C.; Poretti, E.; Provost, J.; Roxburgh, I.; Samadi, R.; Toutain, T. Bibcode: 2006ESASP1306..377A Altcode: Tools developed by helioseismologists and by classical-pulsator astronomers have been used in the hare-and-hound exercises for having a several different ways of deriving the oscillation mode parameters such as frequency or amplitude. These tools are used for deriving what we call recipes that will allow us to obtain the mode parameters from light curves either for solar-like stars or for classical pulsators. The recipes are used for tagging the mode parameters as being those of COROT. They will be used as reference or yardstick for other fitting strategies. We will also address the issue of mode detection. Additional tools such as time-frequency analysis will be presented. Title: The Research and Scientific Support Department of ESA and CoRoT Authors: Fridlund, M.; Beaufort, T.; Favata, F.; Foing, B.; Gimenéz, A.; Gondoin, P.; Johlander, B.; Smit, H.; Sunter, W.; Appourchaux, T. Bibcode: 2006ESASP1306..133F Altcode: No abstract at ADS Title: The Seismology Programme of CoRoT Authors: Michel, E.; Baglin, A.; Auvergne, M.; Catala, C.; Aerts, C.; Alecian, G.; Amado, P.; Appourchaux, T.; Ausseloos, M.; Ballot, J.; Barban, C.; Baudin, F.; Berthomieu, G.; Boumier, P.; Bohm, T.; Briquet, M.; Charpinet, S.; Cunha, M. S.; De Cat, P.; Dupret, M. A.; Fabregat, J.; Floquet, M.; Fremat, Y.; Garrido, R.; Garcia, R. A.; Goupil, M. -J.; Handler, G.; Hubert, A. -M.; Janot-Pacheco, E.; Lambert, P.; Lebreton, Y.; Lignieres, F.; Lochard, J.; Martin-Ruiz, S.; Mathias, P.; Mazumdar, A.; Mittermayer, P.; Montalban, J.; Monteiro, M. J. P. F. G.; Morel, P.; Mosser, B.; Moya, A.; Neiner, C.; Nghiem, P.; Noels, A.; Oehlinger, J.; Poretti, E.; Provost, J.; Renan de Medeiros, J.; De Ridder, J.; Rieutord, M.; Roca-Cortes, T.; Roxburgh, I.; Samadi, R.; Scuflaire, R.; Suarez, J. C.; Theado, S.; Thoul, A.; Toutain, T.; Turck-Chieze, S.; Uytterhoeven, K.; Vauclair, G.; Vauclair, S.; Weiss, W. W.; Zwintz, K. Bibcode: 2006ESASP1306...39M Altcode: 2008arXiv0811.1080M We introduce the main lines and specificities of the CoRoT Seismology Core Programme. The development and consolidation of this programme has been made in the framework of the CoRoT Seismology Working Group. With a few illustrative examples, we show how CoRoT data will help to address various problems associated with present open questions of stellar structure and evolution. Title: SIMU-LC: A Light-Curve Simulator for CoRoT Authors: Baudin, F.; Samadi, R.; Appourchaux, T.; Michel, E. Bibcode: 2006ESASP1306..403B Altcode: In order to prepare the analysis of COROT data, it has been decided to build a simple tool to simulate the expected light curves. This simulation tools takes into account both instrumental constraints and astrophysical inputs for the COROT targets. For example, granulation and magnetic activity signatures are simulated, as well as p modes, with the expected photon noise. However, the simulations rely sometimes on simple approach of these phenomenons, as the main goal of this tool is to prepare the analysis in the case of COROT data and not to perform the most realistic simulations of the different phenomenons. Title: The internal structure of the Sun inferred from g modes and low-frequency p modes Authors: Elsworth, Y. P.; Baudin, F.; Chaplin, W; Andersen, B; Appourchaux, T.; Boumier, P.; Broomhall, A. -M.; Corbard, T.; Finsterle, W.; Fröhlich, C.; Gabriel, A.; García, R. A.; Gough, D. O.; Grec, G.; Jiménez, A.; Kosovichev, A.; Provost, J.; Sekii, T.; Toutain, T.; Turck-Chièze, S. Bibcode: 2006ESASP.624E..22E Altcode: 2006soho...18E..22E The Phoebus group is an international collaboration of helioseismologists, its aim being to detect low-frequency solar g modes. Here, we report on recent work, including the development and application of new techniques based on the detection of coincidences in contemporaneous datasets and the asymptotic properties of the g-mode frequencies. The length of the time series available to the community is now more than ten years, and this has reduced significantly the upper detection limits on the g-mode amplitudes. Furthermore, low-degree p modes can now be detected clearly at frequencies below 1000 μHz. Title: Rotation inversions of artificial solarFLAG Sun-as-a-star data Authors: Chaplin, W. J.; Sekii, T.; Appourchaux, T.; Baudin, F.; Boumier, P.; Corbard, T.; Elsworth, Y.; Fletcher, S. T.; Garcia, R. A.; Jiménez-Reyes, S. J.; Lazrek, M.; New, R.; Salabert, D.; Toutain, T.; Wachter, R. Bibcode: 2006ESASP.624E..82C Altcode: 2006soho...18E..82C No abstract at ADS Title: Recent Progresses on g-Mode Search Authors: Appourchaux, T.; Andersen, B.; Baudin, F.; Boumier, P.; Broomhall, A. -M.; Chaplin, W.; Corbard, T.; Elsworth, Y.; Finsterle, W.; Fröhlich, C.; Gabriel, A.; Garcia, R.; Gough, D. O.; Grec, G.; Jiménez, A.; Kosovichev, A.; Provost, J.; Sekii, T.; Toutain, T.; Turck-Chièze, S. Bibcode: 2006ESASP.617E...2A Altcode: 2006soho...17E...2A No abstract at ADS Title: Solar FLAG hare and hounds: on the extraction of rotational p-mode splittings from seismic, Sun-as-a-star data Authors: Chaplin, W. J.; Appourchaux, T.; Baudin, F.; Boumier, P.; Elsworth, Y.; Fletcher, S. T.; Fossat, E.; García, R. A.; Isaak, G. R.; Jiménez, A.; Jiménez-Reyes, S. J.; Lazrek, M.; Leibacher, J. W.; Lochard, J.; New, R.; Pallé, P.; Régulo, C.; Salabert, D.; Seghouani, N.; Toutain, T.; Wachter, R. Bibcode: 2006MNRAS.369..985C Altcode: 2006MNRAS.tmp..515C; 2006astro.ph..6748C We report on results from the first solar Fitting at Low-Angular degree Group (solar FLAG) hare-and-hounds exercise. The group is concerned with the development of methods for extracting the parameters of low-l solar p-mode data (`peak bagging'), collected by Sun-as-a-star observations. Accurate and precise estimation of the fundamental parameters of the p modes is a vital pre-requisite of all subsequent studies. Nine members of the FLAG (the `hounds') fitted an artificial 3456-d data set. The data set was made by the `hare' (WJC) to simulate full-disc Doppler velocity observations of the Sun. The rotational frequency splittings of the l = 1, 2 and 3 modes were the first parameter estimates chosen for scrutiny. Significant differences were uncovered at l = 2 and 3 between the fitted splittings of the hounds. Evidence is presented that suggests this unwanted bias had its origins in several effects. The most important came from the different way in which the hounds modelled the visibility ratio of the different rotationally split components. Our results suggest that accurate modelling of the ratios is vital to avoid the introduction of significant bias in the estimated splittings. This is of importance not only for studies of the Sun, but also of the solar analogues that will be targets for asteroseismic campaigns.

Solar FLAG URL: http://bison.ph.bham.ac.uk/~wjc/Research/FLAG.html

E-mail: wjc@bison.ph.bham.ac.uk ‡

George Isaak passed away in 2005 June 5, prior to the completion of this work. He is greatly missed by us all. Title: Can we finally solve the problems of "Coronal Heating " and "Solar Wind Acceleration" in the Cosmic Vision era ? Authors: Maksimovic, M.; Appourchaux, T.; Aulanier, G.; Chust, T.; Dudok de Wit, T.; Klein, K. L.; Krasnoselskikh, V.; Louarn, P.; Roux, A.; Vial, J. C. Bibcode: 2006cosp...36.2999M Altcode: 2006cosp.meet.2999M Since the discovery of the corona s million-degree temperature in the 1940s and the supersonic solar wind in the early 1960s major efforts have been made to discover the physical mechanisms that could explain these two observations These efforts have led to a tremendous increase in our knowledge of our neighbour star the inner heliosphere and the Sun-Earth connections Unfortunately these efforts haven t allowed to provide a definitive answer to these questions Why such a situation On one hand the remote-sensing strategy has tried to probe the coronal properties by basically analysing the photons emitted or absorbed by the Sun s atmosphere With this regards limitations occur on both theoretical ground physics of the coupling between photons and plasma and experimental ground limited number of observables such as spectral lines or the hardly solvable problem of the line of sight integration On the other hand solar wind in-situ measurements have had access to the very detailed state of the local plasma properties full particles velocity distribution functions observations of the electromagnetic plasma fluctuations over a huge frequency range but at locations far from the corona and the solar wind acceleration regions Moreover it has been realized more recently that the magnetic field plays a fundamental role in shaping the low corona and channelling the energy inputs Unfortunately the measurement of the full magnetic vector in the corona is a very difficult enterprise and this lack of information hampers all on-going modelling efforts Given Title: The Beleinos cornerstone: the Sun, the star close to Earth Authors: Appourchaux, T.; Auchère, F.; Bocchialini, K.; Bonnet, R. M.; Gabriel, A.; Vial, J. -C. Bibcode: 2005ESASP.588..389A Altcode: 2005tssc.conf..389A No abstract at ADS Title: The magnetism of the solar interior for a complete MHD solar vision Authors: Turck-Chièze, S.; Appourchaux, T.; Ballot, J.; et al. Bibcode: 2005ESASP.588..193T Altcode: 2005astro.ph.10854T; 2005tssc.conf..193T The solar magnetism is no more considered as a purely superficial phenomenon. The SoHO community has shown that the length of the solar cycle depends on the transition region between radiation and convection. Nevertheless, the internal solar (stellar) magnetism stays poorly known. Starting in 2008, the American instrument HMI/SDO and the European microsatellite PICARD will enrich our view of the Sun-Earth relationship. Thus obtaining a complete MHD solar picture is a clear objective for the next decades and it requires complementary observations of the dynamics of the radiative zone. For that ambitious goal, space prototypes are being developed to improve gravity mode detection. The Sun is unique to progress on the topology of deep internal magnetic fields and to understand the complex mechanisms which provoke photospheric and coronal magnetic changes and possible longer cycles important for human life. We propose the following roadmap in Europe to contribute to this "impressive" revolution in Astronomy and in our Sun-Earth relationship: SoHO (1995-2007), PICARD (2008-2010), DynaMICS (2009-2017) in parallel to SDO (2008-2017) then a world-class mission located at the L1 orbit or above the solar poles. Title: Working group report on Asteroseismology and stellar activity from Dome C Authors: Bouchy, F.; Mosser, B.; Catala, C.; Appourchaux, T.; Bouvier, J.; Chadid, M.; Donati, J. F.; Fossat, E.; Schmider, F. X.; Thevenin, F.; Vauclair, G. Bibcode: 2005sf2a.conf..329B Altcode: This paper presents the conclusions of the working group for stellar physics observations at the Dome-C station in Antarctica. It summarizes the advantages of Dome-C for asteroseismology and stellar activity, identifies strategies and possible instrumental projects to be conducted there, and concludes with recommendations for the development of stellar observations. The conclusions are based on the fact that continuous observations over several weeks or months without breaks due to the diurnal cycle are fundamental for programs of stellar physics and especially for asteroseismology and stellar activity. Therefore, Dome-C appears to be a unique ground-based site offering ideal conditions for continuous observations. Title: The life of stars and their planets Authors: Catala, C.; Aerts, C.; Aigrain, S.; Antonello, E.; Appourchaux, T.; Auvergne, M.; Baglin, A.; Barge, P.; Barstow, M. A.; Baudin, F.; Boumier, P.; Collier Cameron, A.; Christensen-Dalsgaard, J.; Cutispoto, G.; Deeg, H.; Deleuil, M.; Desidera, S.; Donati, J. -F.; Favata, F.; Foing, B. H.; Gameiro, J. F.; Garcia, R.; Garrido, F.; Horne, K.; Lanza, A. F.; Lanzafame, A. C.; Lecavelier Des Etangs, A.; Léger, A.; Mas-Hesse, M.; Messina, S.; Micela, G.; Michel, E.; Monteiro, M. J. P. F. G.; Mosser, B.; Noels, A.; Pagano, I.; Piotto, G.; Poretti, E.; Rauer, H.; Roca-Cortes, T.; Rodono, M.; Rouan, D.; Roxburgh, I.; Schneider, J.; Strassmeier, K.; Turck-Chièze, S.; Vauclair, S.; Vidal-Madjar, A.; Weiss, W. W.; Wheatley, P. Bibcode: 2005ESASP.588...99C Altcode: 2005tssc.conf...99C We lack a reliable scenario for the formation and evolution of stars and their planetary systems, involving key factors such as magnetic fields and turbulence. We present the case for a mission concept that will clarify these problems and give us a global view of the evolution of combined star and planetary systems. This will be achieved by simultaneously addressing the search for planetary transits in front of a large number of stars, including many nearby stars, the study of their internal structure and evolution via asteroseismology, and that of their magnetic activity, via UV monitoring. Title: The luminosity oscillations imager, a space instrument: from design to science Authors: Appourchaux, Thierry Bibcode: 2005pmds.book..185A Altcode: No abstract at ADS Title: Innovative designs for the imaging suite on Solar Orbiter Authors: Auchere, Frederic; Song, Xueyen; Rouesnel, Frederic; Appourchaux, Thierry; Fourmon, Jean-Jacques; Le Clec'h, Jean-Christophe; Berthe, Michel; Defise, Jean-Marc; Mazy, Emmanuel; Rochus, Pierre L.; Mercier, Raymond; Ravet, Marie-Francoise Bibcode: 2005SPIE.5901..298A Altcode: Orbiting around the Sun on an inclined orbit with a 0.2 UA perihelion, the Solar Orbiter probe will provide high resolution views of the Sun from various angles unattainable from Earth. Together with a set of high resolution imagers, the Full Sun Imager is part of the EUV Imaging suite of the Solar Orbiter mission. The mission's ambitious characteristics draw severe constraints on the design of these instruments. We present a photometrically efficient, compact, and lightweight design for the Full Sun Imager. With a 5 degrees field of view, this telescope will be able to see the global solar coronal structure from high viewing angles. Thermal solutions reducing the maximum power trapped in the High Resolution Imagers are also proposed. Title: Inferred acoustic rates of solar p modes from several helioseismic instruments Authors: Baudin, F.; Samadi, R.; Goupil, M. -J.; Appourchaux, T.; Barban, C.; Boumier, P.; Chaplin, W. J.; Gouttebroze, P. Bibcode: 2005A&A...433..349B Altcode: Acoustic rates of excitation of solar p modes can be estimated from observations in order to place constraints on the modelling of the excitation process and the layers where it occurs in the star. For several reasons (including a poor signal to noise ratio and mode overlap), this estimation is difficult. In this work, we use three completely independent datasets to obtain robust estimates in the solar case for ℓ=1 modes. We also show that the height in the solar atmosphere where the modes are observed must be taken into account. Our three sets of results are shown to be consistent, particularly in the lower part of the p-mode spectrum (from 1.8 mHz to 2.8 mHz). At higher frequencies, the agreement is not as good, because of a larger dispersion of the measurements and also because of some systematic differences which might be due to observation height estimation or to a systematic influence of the noise. Title: On measuring planetary winds using high-resolution spectroscopy in visible wavelengths Authors: Civeit, T.; Appourchaux, T.; Lebreton, J. -P.; Luz, D.; Courtin, R.; Neiner, C.; Witasse, O.; Gautier, D. Bibcode: 2005A&A...431.1157C Altcode: We present a new method that uses high-resolution spectroscopy in the visible wavelength domain to measure planetary winds. A rotating atmosphere illuminated by the Sun induces a Doppler shift in the back-scattered solar light. Its analysis with a cross-dispersed echelle spectrometer allows the direct determination of both the wind speed and direction. We describe in this paper the image and data processing algorithms used in the method and implemented in a data reduction and analysis package. Since the velocity of planetary winds leads to Doppler shifts smaller than the width of the solar lines, accurate Doppler measurements are performed by running the algorithm proposed by [CITE], which is an optimum technique using the full available spectral information. We apply the method to Io as a test case, a small slowly-rotating body with no atmosphere, to measure its solid rotation. The observations span wavelengths from 414 to 621 nm and were carried out with the Ultraviolet and Visual Echelle Spectrograph (UVES) on the 8.2 m Kueyen unit at the Very Large Telescope (VLT ESO). The results we obtain for Io validate the principle of the method by optimally measuring the well-known surface rotational velocity of this moon, with an uncertainty smaller than 2 m s-1. However, the analysis of the set of observations shows that systematic errors are large and one needs to consider the retrieved velocity as a lower limit. Title: On the detection of pure sine waves embedded in a spectrum of stochastically excited p modes Authors: Moreira, O.; Appourchaux, T.; Berthomieu, G.; Toutain, T. Bibcode: 2005MNRAS.357..191M Altcode: 2005MNRAS.tmp...16M The mode identification and fitting of solar oscillations provide an observational tool to derive the physical properties of the Sun's interior. What has been devised for helioseismology can now be used for future asteroseismology ground-based instruments and space missions, such as the High-Accuracy Radial Velocity Planetary Searcher (HARPS) and Convection, Rotation and Planetary Transits (COROT). In the coming decade, numerous stars will be observed for which new tools will be needed. For instance, it is very likely that g and p modes will be detected, rendering the identification difficult. In addition, modes having both characteristics, known as mixed modes, are also likely to be detected in evolved stars; these latter modes are crucial for the understanding of the internal structure of the stars as they propagate deeply inside the stars, unlike the p modes. Unfortunately, the mixing will not only occur physically but also in the frequency domain: mixed modes will appear very close to stochastically excited p modes. In this paper, we have devised a new technique for detecting long-lived modes (mixed or g modes) embedded in a common p-mode spectrum. The technique has been validated using Monte Carlo simulations. In the framework of the hare-and-hound exercise of COROT, this technique has been applied to synthetic time series of the evolved solar-like star HD 57006. The results show that we can detect most of the mixed modes embedded by the hare. We also discuss the impact of how the long-lived modes are excited on the detection level. The technique described here can be applied to stars with a mass greater than 1.2 Msolar, having evolved possibly beyond the terminal-age main sequence, such as Procyon. Title: Characterization of the Zonal Wind Flow in the Upper Atmosphere of Titan with the VLT Authors: Courtin, Régis; Luz, David; Gautier, Daniel; Appourchaux, Thierry; Lebreton, Jean-Pierre; Ferri, Francesca; Lara, Luisa; Hourdin, Frédéric; Kaufer, Andreas Bibcode: 2005HiA....13..897C Altcode: No abstract at ADS Title: On detecting short-lived p modes in a stellar oscillation spectrum Authors: Appourchaux, T. Bibcode: 2004A&A...428.1039A Altcode: The false alarm probability for detecting peaks embedded in a power spectrum of noise was given by \cite{Scargle82}. This test has been used in helioseismology to detect long-lived modes such as g modes \citep{TA2000}. With the development of asteroseismology, there is now a need to define a similar test but for short-lived p modes. In this article, I define a false alarm test for detecting short-lived p modes, and I give the probability of detecting such modes given their signal-to-noise ratio, their linewidths and the duration of observation. Title: Flag Hare-And Exercise: on the Extraction of Sectoral Mode Splittings from Full-Disc Sun-As Data Authors: Chaplin, W. J.; Appourchaux, T.; Baudin, F.; Boumier, P.; Elsworth, Y.; Fletcher, S. T.; Fossat, E.; García, R. A.; Isaak, G. R.; Jiménez, A.; Jiménez-Reyes, S. J.; Lazrek, M.; Lochard, J.; New, R.; Pallé, P.; Régulo, C.; Salabert, D.; Toutain, T. Bibcode: 2004ESASP.559..356C Altcode: 2004soho...14..356C No abstract at ADS Title: a Radial Velocity Search for P-Modes in VIR Authors: Martic, M.; Lebrun, J. C.; Appourchaux, T.; Schmitt, J. Bibcode: 2004ESASP.559..563M Altcode: 2004astro.ph..9126M; 2004soho...14..563M Spectroscopic high-resolution observations were performed with fiber-fed cross-dispersed echelle spectrographs in order to measure the fluctuations in radial velocities of a sample of bright stars that are likely to undergo solar-like oscillations. Here we report the results for beta Vir (HR4540) from two observing runs carried out in February 2002 with FEROS at the ESO 1.52 m telescope in La Silla (Chile) and ELODIE spectrograph at 1.93 OHP telescope (Observatoire de Haute Provence, France). The analysis of the time series of Doppler shifts from both sites has revealed the presence of an excess power around 1.7 mHz. We discuss the interpretation of this data set in terms of possible p-mode oscillations. Title: On comparing estimates of low-l solar p-mode frequencies from Sun-as-a-star and resolved observations Authors: Chaplin, W. J.; Appourchaux, T.; Elsworth, Y.; Isaak, G. R.; Miller, B. A.; New, R. Bibcode: 2004A&A...424..713C Altcode: Low-angular-degree (low-l) solar p modes provide a sensitive probe of the radiative interior and core of the Sun. Estimates of their centroid frequencies can be used to constrain the spherically symmetric structure of these deep-lying layers. The required data can be extracted from two types of observation: one where the modes are detected in integrated sunlight, i.e., a Sun-as-a-star view; and a second where the visible disc is imaged onto many pixels, and the collected images then decomposed into their constituent spherical harmonics. While the imaging strategy provides access to all of the individual components of a multiplet, the Sun-as-a-star technique is sensitive to only about two thirds of these (average over l=0 to 3) with those modes that are detected having different levels of visibility. Because the various components can have contrasting spatial structure over the solar surface, they can respond very differently to changes in activity along the solar cycle. Since the Sun-as-a-star and resolved analyses take as input a different ``subset'' of modes, the extracted frequency estimates are expected to differ depending upon the phase of the cycle. Differences also arise from the types of models used to fit the modes. Here, we present expressions that allow the sizes of these differences to be predicted. Title: p-mode frequencies in solar-like stars. I. Procyon A Authors: Martić, M.; Lebrun, J. -C.; Appourchaux, T.; Korzennik, S. G. Bibcode: 2004A&A...418..295M Altcode: 2004astro.ph..3035M As a part of an on-going program to explore the signature of p-modes in solar-like stars by means of high-resolution absorption line spectroscopy, we have studied four stars (α CMi, η Cas A, ζ Her A and β Vir). We present here new results from two-site observations of Procyon A acquired over twelve nights in 1999. Oscillation frequencies for l=1 and 0 (or 2) p-modes are detected in the power spectra of these Doppler shift measurements. A frequency analysis points out the difficulties of the classical asymptotic theory in representing the p-mode spectrum of Procyon A.

Based on observations obtained at the Observatoire de Haute-Provence (CNRS, France) and at the Whipple Observatory (Arizona, USA). Title: Solar p-mode frequencies at ℓ=2: What do analyses of unresolved observations actually measure? Authors: Chaplin, W. J.; Appourchaux, T.; Elsworth, Y.; Isaak, G. R.; Miller, B. A.; New, R.; Toutain, T. Bibcode: 2004A&A...416..341C Altcode: We have studied in detail the extraction of estimates of ℓ=2 p-mode frequencies from unresolved observations of the visible disc of the Sun. Examples of data of this type include ground-based observations made by the Birmingham Solar-Oscillations Network (BiSON), and space-borne observations made by the GOLF and VIRGO/SPM instruments on board the ESA/NASA SOHO satellite. The fitting of the modes is complicated in practice by the asymmetric arrangement in frequency of the three components (m=-2, 0 and 2) that are prominent in such data. In order to investigate the effect of this we used a series of 10-yr artificial datasets into which varying degrees of asymmetry were introduced. The sets were designed to mimic the characteristics of the BiSON and GOLF data, and were analyzed both with and without the BiSON window function from the period 1992 through 2001. Since reliable estimates of the asymmetry have only recently been extracted from unresolved observations (Chaplin et al. \cite{Chaplin03}a) it has for a long time been standard practice to fit the ℓ=2 modes to a model that assumes a symmetrically arranged multiplet. We have tested the impact of this on the accuracy of the extracted frequencies. Furthermore, we demonstrate that asymmetric models can be successfully applied, provided the data are of sufficient length and quality. We also discuss the implications of our simulations for analyses of real solar data. Title: Development of imaging arrays for solar UV observations based on wide band gap materials Authors: Schuehle, Udo H.; Hochedez, Jean-Francois E.; Pau, Jose Luis; Rivera, Carlos; Munoz, Elias; Alvarez, Jose; Kleider, Jean-Paul; Lemaire, Philippe; Appourchaux, Thierry; Fleck, Bernhard; Peacock, Anthony; Richter, Mathias; Kroth, Udo; Gottwald, Alexander; Castex, Marie-Claude; Deneuville, Alain; Muret, Pierre; Nesladek, Milos; Omnes, Franck; John, Joachim; Van Hoof, Chris Bibcode: 2004SPIE.5171..231S Altcode: Solar ultraviolet imaging instruments in space pose most demanding requirements on their detectors in terms of dynamic range, low noise, high speed, and high resolution. Yet UV detectors used on missions presently in space have major drawbacks limiting their performance and stability. In view of future solar space missions we have started the development of new imaging array devices based on wide band gap materials (WBGM), for which the expected benefits of the new sensors - primarily visible blindness and radiation hardness - will be highly valuable. Within this initiative, called "Blind to Optical Light Detectors (BOLD)", we have investigated devices made of AlGa-nitrides and diamond. We present results of the responsivity measurements extending from the visible down to extreme UV wavelengths. We discuss the possible benefits of these new devices and point out ways to build new imaging arrays for future space missions. Title: Global fitting of power spectra of solar-like stars Authors: Neiner, C.; Appourchaux, T. Bibcode: 2004ESASP.538..373N Altcode: 2004sshp.conf..373N Helioseismology has been able to provide the internal structure of the Sun and its dynamics. These inferences have been made possible by inverting the frequencies and rotational splitting of the p-mode oscillations. Thanks to asteroseismology, similar results can now be obtained for stars other than the Sun. For this purpose, we are developing a numerical code for global fitting of power spectra. The code is currently developed and tested on full-disk integrated solar data obtained with the SOHO/LOI instrument. It will then be applied to synthetic data from the hare-and-hound exercises of COROT. The final goal is to apply the technique to data of solar-like stars obtained with the COROT and Eddington satellites to infer the internal structure and dynamics of those stars. Title: Mode extraction from time series: from the challenges of COROT to those of Eddington Authors: Appourchaux, T.; Moreira, O.; Berthomieu, G.; Toutain, T. Bibcode: 2004ESASP.538..109A Altcode: 2004sshp.conf..109A With more than 30 years of experience in extraction of eigenmodes from power spectra of solar signals, we are now almost ready to apply this knowledge onto the forecoming missions: COROT and Eddington. However the fitting task differs by 3 orders of magnitude; COROT will be able to get time series of stellar light for some 30 stars, while Eddington will be able to gather such data for about 50000 stars. While for COROT, our current tools can be applied by hand, the case of Eddington is significantly more complex. We are looking forward having automatic fitting procedures that will allow to recover mode parameters for about 90% of the solar-like stars. Unfortunately, about 10% of these stars will require some more delicate attention that will cost time to take care of. We will use the example of the infamous HD 57006, known to be quite evolved with a difficult eigenmode spectrum, to explain how a star can evolve from an easy-to-fit target (90% of the solar-like stars) to a difficult-to-fit (10% of the remaining stars). In the latter case, new techniques for detecting narrow peaks (g-mode like) out of broad peaks (p-mode like) has been devised in the context of the hare-and-hound exercise of COROT. This and other techniques will be used to implement the automatic fitting procedure for the remaining 10% of Eddington solar-like stars. Title: On Maximum Likelihood Estimation of averaged power spectra Authors: Appourchaux, T. Bibcode: 2003A&A...412..903A Altcode: It is custom in helioseismology to assume that the power spectra of time series of solar radial velocity or of solar intensity have a χ2 with 2 degrees of freedom statistics. This assumption is regularly used in helioseismology for using Maximum Likelihood Estimators for single power spectra with that assumed statistics. When independent power spectra are added, it is also custom to assume that the resulting power spectra can be approximated by a Gaussian distribution. Here we show that this approximation is irrelevant, and that the software code developed for fitting single power spectra can be used without any approximation after proper normalization of the added power spectra. Title: Characterization of the zonal wind in Titan's stratosphere with UVES Authors: Luz, D.; Courtin, R.; Gautier, D.; Appourchaux, T.; Ferri, F.; Lebreton, J. -P.; Lara, L.; Hourdin, F.; Kaufer, A. Bibcode: 2003EAEJA.....2941L Altcode: We will report on recent efforts to characterize the zonal wind flow in Titan's stratosphere. We have used the UVES echelle spectrometer mounted at VLT-UT2 to obtain high-resolution solar spectra reflected off Titan. The purpose of the observations, which were done in February 2002, has been to detect the differential Doppler shift induced by the zonal wind flow in the back-scattered solar radiation from the East and West limbs of Titan. Since the wind speed should not exceed 200 m/s, an absolute detection of the shift on single solar lines is not feasible due to the limited spectral resolution of UVES. This is why we apply a retrieval scheme developed for stellar accelerometry (Connes P. 1985, ApSS 110, 211; Martyc M. et al. 1999, A&A 351, 993) which makes use of the full spectral range (∼ 4200 to 6200 Angstroms for the red arm of the instrument) and takes into account all the lines present in the spectrum. Preliminary results indicate that the wind is prograde. Title: The search for g modes Authors: Appourchaux, T. Bibcode: 2003ESASP.517..131A Altcode: 2003soho...12..131A The Phoebus group was set up about 5 years ago with the expressed purpose to detect the g modes predicted by helioseismology to occur in the sun. The current status will be reviewed including new approaches proposed by other groups in the field. Over the years, the upper limit to g-mode amplitude set by Appourchaux et al. (2000) (10 mm/s at 10 σ) has been lowered due to a longer time series as well as new detection techniques. Not withstanding these efforts the chance of a positive detection still appears remote with the current upper limit still way above that predicted by helioseismology. New techniques in particular observations involving limb intensity and/or velocity cross-correlations against various observables, or even the detection of gravitational waves may offer the best hope for a future positive detection. Title: New UV detectors for solar observations Authors: Hochedez, Jean-Francois E.; Schuehle, Udo H.; Pau, Jose L.; Alvarez, Jose; Hainaut, Olivier; Appourchaux, Thierry P.; Auret, F. D.; Belsky, Andrei; Bergonzo, Philippe; Castex, M. C.; Deneuville, A.; Dhez, Pierre; Fleck, Bernhard; Haenen, Ken; Idir, Mourad; Kleider, Jean Paul; Lefeuvre, Elie; Lemaire, Philippe; Monroy, E.; Muret, P.; Munoz, Elias; Nesladek, Milos; Omnes, Franck; Pace, Emanuele; Peacock, Anthony J.; Van Hoof, Chris A. Bibcode: 2003SPIE.4853..419H Altcode: BOLD (Blind to the Optical Light Detectors) is an international initiative dedicated to the development of novel imaging detectors for UV solar observations. It relies on the properties of wide bandgap materials (in particular diamond and Al-Ga-nitrides). The investigation is proposed in view of the Solar Orbiter (S.O.) UV instruments, for which the expected benefits of the new sensors -primarily visible blindness and radiation hardness- will be highly valuable. Despite various advances in the technology of imaging detectors over the last decades, the present UV imagers based on silicon CCDs or microchannel plates exhibit limitations inherent to their actual material and technology. Yet, the utmost spatial resolution, fast temporal cadence, sensitivity, and photometric accuracy will be decisive for the forthcoming solar space missions. The advent of imagers based on wide-bandgap materials will permit new observations and, by simplifying their design, cheaper instruments. As for the Solar Orbiter, the aspiration for wide-bandgap material (WBGM) based UV detectors is still more sensible because the spacecraft will approach the Sun where the heat and the radiation fluxes are high. We describe the motivations, and present the program to achieve revolutionary flight cameras within the Solar Orbiter schedule as well as relevant UV measurements. Title: Characterization of Titan's Zonal Wind Flow with the VLT Authors: Courtin, Regis; Luz, D.; Gautier, D.; Appourchaux, T.; Ferri, F.; Lebreton, J. -P.; Lara, L.; Hourdin, F.; Kaufer, A. Bibcode: 2003IAUSS...1E..33C Altcode: We will report on recent efforts to characteize the zonal wind flow in Titan's upper atmosphere. We used the UVES echelle spectrometer at the focus of the VLT-UT2 to obtain high-resolution Titan raeflection spectra in the visible from 420 to 630 nm. The purpose of the observations which were carried out in February 2002 was to detect the differential Doppler shift induced by the zonal wind flowin the back-scattered solar radiation from the Eastern and Western limbs of Titan. The measured spectra were analyzed withthe help of a velocity retrieval scheme developed for stellar accelerometry taking into account all of the solar lines present in the observed spectral range (Connes 1985 ApSS 110 211; Martyc et al. 1999 AA 351 993). Preliminary results indicate that the wind is prograde and that the wind speed is consistent with model predictions. Title: Observations of the Sun's magnetic field during the recent solar maximum Authors: Sanderson, T. R.; Appourchaux, T.; Hoeksema, J. T.; Harvey, K. L. Bibcode: 2003JGRA..108.1035S Altcode: We present new observations and analyses of the Sun's magnetic field and coronal holes. Using magnetic field observations from the Wilcox Solar Observatory, we present a simple means whereby the tilt angle of the current sheet can be calculated. We use a data set covering the last 26 years, which shows for the first time how the dipole component rotated once during a full 22-year solar cycle. We show how this influenced the current sheet. At solar minimum, the Sun's coronal magnetic field was essentially dipolar and aligned parallel to the spin axis. As a result, the heliospheric current sheet was flat and had very little warp. Around solar maximum, the dipole was perpendicular to the spin axis, and the ratio of quadrupole to dipole strength was high for much of the time. This meant that the current sheet was tilted and highly warped, and reached up to high latitudes. Surprisingly, there were also times close to solar maximum when the quadrupole/dipole ratio was low, and the current sheet was relatively flat, but still highly inclined. We apply for the first time to solar magnetic data a method, which quantitatively analyses the quadrupole component of the magnetic field. From the terms of the expansion of the observed photospheric magnetic field, we compute the position of the poles of the magnetic field. We combine for the first time over an extended period of time magnetic field data from the Wilcox Solar Observatory with coronal hole positions taken from the National Solar Observatory/Kitt Peak. We find that the position of the coronal holes followed the motion of the poles of the magnetic field as the poles moved over the surface of the Sun and that the polar coronal holes broke up into groups of smaller like-polarity holes as the poles approached the midlatitude regions and the quadrupole became more important. We discuss the implications for energetic particle observations at Ulysses. Title: Peak Bagging for Solar-like Stars Authors: Appourchaux, Thierry Bibcode: 2003Ap&SS.284..109A Altcode: The identification of the low-degree p modes in other stars is the challenge of future asteroseismology space missions such as COROT, MONS, MOST or Eddington. The identification is based on a priori knowledge of the characteristics of the modes. We shall review the most common assumptions needed for the identification such as basic stellar structure, visibilities, rotational splittings or linewidths. We shall describe a few tools needed for facilitating the identification. As soon as modes are properly identified, the peakbagging of the mode characteristics can be done using Maximum Likelihood Estimation. We give examples of the whole process using solar data and hare-and-hound exercises performed in the frame work of the COROT project. Title: Hare &Hound Exercise with Simulated COROT Data Authors: Berthomieu, G.; Appourchaux, T.; COROT Seismology Working Group Bibcode: 2003aahd.conf..465B Altcode: No abstract at ADS Title: Peak finding at low signal-to-noise ratio: low-ℓ solar acoustic eigenmodes at n≤9 from the analysis of BiSON data Authors: Chaplin, W. J.; Elsworth, Y.; Isaak, G. R.; Marchenkov, K. I.; Miller, B. A.; New, R.; Pinter, B.; Appourchaux, T. Bibcode: 2002MNRAS.336..979C Altcode: We make use of 9 yr of full-disc helioseismic data - as collected by the ground-based Birmingham Solar-Oscillations Network (BiSON) - to search for low-frequency, low-angular-degree (low-l) acoustic modes. A range of tests are applied to the power spectrum of the observations that search for prominent mode-like structure: strong spikes, structure spanning several bins signifying the presence of width (from damping), and the occurrence of prominent multiplet structure at l>= 1 arising principally from the solar rotation and made from several spikes separated suitably in frequency. For each test we present analytical expressions that allow the probability that the uncovered structure is part of the broad-band noise background to be assessed. These make use of the cumulative binomial (Bernoulli) distribution and serve to provide an objective measure of the significance of the detections. This work has to date uncovered nine significant detections of non-broad-band origin that we have identified as low-l modes with radial overtone numbers n<= 9. Title: Characterization of the Zonal Wind Flow in the Stratosphere of Titan with UVES Authors: Luz, D.; Courtin, R.; Gautier, D.; Ferri, F.; Appourchaux, T.; Lebreton, J. -P.; Cabane, M.; Rannou, P.; Hourdin, F.; Lara, L.; Kaufer, A. Bibcode: 2002DPS....34.3405L Altcode: 2002BAAS...34..901L We will report on recent efforts to characterize the zonal wind flow in Titan's stratosphere. We used the UVES echelle spectrometer at the focus of the UT2 of the Very Large Telescope at Paranal, Chile, to measure the reflection spectrum of Titan between 4200 and 6200 angstrom with a resolution of 80,000. The purpose of these observations, which were carried out in February 2002, is to detect the differential Doppler shift induced by the zonal wind flow between the East and West limbs of Titan. However, because the wind speed is not expected to exceed 200 m/s, an absolute detection of the Doppler shift on isolated solar lines is not feasible, even at the spectral resolution of UVES. Therefore, we have made use of a retrieval scheme developed for absolute stellar accelerometry (Connes 1985, ApSS 110, 211; Martic et al. 1999, A&A 351, 993) to extract the velocity signal by simultaneously taking into account all the lines present in the spectrum. We will describe the method and discuss preliminary results. Research supported by the "Programme National de Planetologie" of the Institut National des Sciences de l'Univers (France). D. Luz acknowledges financial support by the Portuguese Foundation for Science and Technology, ref.SFRH-BPD-3630-2000. Title: A search for solar g modes in the GOLF data Authors: Gabriel, A. H.; Baudin, F.; Boumier, P.; García, R. A.; Turck-Chièze, S.; Appourchaux, T.; Bertello, L.; Berthomieu, G.; Charra, J.; Gough, D. O.; Pallé, P. L.; Provost, J.; Renaud, C.; Robillot, J. -M.; Roca Cortés, T.; Thiery, S.; Ulrich, R. K. Bibcode: 2002A&A...390.1119G Altcode: With over 5 years of GOLF data having some 90% continuity, a new attempt has been made to search for possible solar g modes. Statistical methods are used, based on the minimum of assumptions regarding the solar physics; namely that mode line-widths are small compared with the inverse of the observing time, and that modes are sought in the frequency interval 150 to 400 mu Hz. A number of simulations are carried out in order to understand the expected behaviour of a system consisting principally of a solar noise continuum overlaid with some weak sharp resonances. The method adopted is based on the FFT analysis of a time series with zero-padding by a factor of 5. One prominent resonance at 284.666 mu Hz coincides with a previous tentative assignment as one member of an n=1, l=1, p-mode multiplet. Components of two multiplets, previously tentatively identified as possible g-mode candidates from the GOLF data in 1998, continue to be found, although their statistical significance is shown to be insufficient, within the present assumption regarding the nature of the signal. An upper limit to the amplitude of any g mode present is calculated using two different statistical approaches, according to either the assumed absence (H0 hypothesis) or the assumed presence (H1 hypothesis) of a signal. The former yields a slightly lower limit of around 6 mm/s. Title: What have we learnt with the Luminosity Oscillations Imager over the past 6 years? Authors: Appourchaux, T.; Andersen, B.; Sekii, T. Bibcode: 2002ESASP.508...47A Altcode: 2002soho...11...47A We summarize what we achieved with 6 years of LOI data. We present old as well as new results regarding the p-mode parameters dependence upon solar activity. We have also derived the dependence of the solar background noise upon solar activity and solar disk position. Inversions done using LOI frequencies and higher-degree mode frequencies from GONG confirm previous velocity inversions. Title: Observations of The Sun's Coronal Magnetic Field and Coronal Holes During The Ulysess Fast Latitude Scan Authors: Sanderson, T. R.; Appourchaux, T.; Hoeksema, J. T.; Harvey, K. L. Bibcode: 2002EGSGA..27..595S Altcode: We have combined magnetic field observations from the Wilcox Solar Observatory and coronal holes observations from the Kitt Peak Observatory to investigate how the Sun's magnetic field behaved during the Ulysses fast latitude scan.

Using the dipole and quadrupole terms in the expansion of the coronal magnetic field, we show that the dipole rotated once every 22-year solar cycle and that the quadrupole term reached a maximum at the time of solar maximum. At solar minimum, the current sheet was flat and had very little warp, but around solar maximum, during the second Ulysses Southern Polar Pass, the ratio of quadrupole to dipole strength was high for much of the time. The current sheet was tilted and highly warped, and reached up to high latitudes. Surprisingly, there were times when the quadrupole/dipole ratio was low, and the current sheet was relatively flat, but still highly inclined.

The site of coronal holes follows the motion of the poles of the magnetic field as the poles move over the surface of the Sun. The polar coronal hole breaks up into groups of smaller like-polarity holes as the poles approach the mid-latitude regions. Title: Variation of acoustic mode centroid frequencies over the solar cycle Authors: Chaplin, W. J.; Appourchaux, T.; Elsworth, Y.; Isaak, G. R.; New, R. Bibcode: 2002AdSpR..29.1881C Altcode: Together with a brief historical overview, we use high-quality helioseismic data collected by three different observational programmes during the declining phase of activity cycle 22, and a substantial portion of the rising phase of the current cycle (23), to study the phenomenological nature of the cycle-induced (centroid) eigenfrequencies. Our analyses (for 1600 ≤ ν ≤ 4000 μHz) make use of observations made by the ground-based GONG over the angular degree range 4 ≤ l ≤ 150; the ground-based BiSON over 0 ≤ l ≤ 2; and the VIRGO/LOI instrument on board the ESA/NASA SOHO satellite over 0 ≤ l ≤ 8. We show that GONG shifts averaged over different ranges in l, together with the BiSON and LOI data averaged over their full quoted ranges, all scale at a given frequency with the normalized mode inertia ratio Qnl (Christensen-Dalsgaard & Berthomieu 1991). This is to be expected if the time-dependent perturbation affecting the modes is confined in the surface layers; the excellent agreement also reflects favourably on the external consistency of the different observations. We have also analyzed the frequency dependence of the shifts by fitting a power-law of the form δν nl ∝ (ν nl/ Enl to the data (where the Enl are the mode inertias, and α is the power-law index to be extracted). Previous studies have suggested that a relation with α = 0 provides an adequate description of the shifts up to ν ≈ 3500 μHz. However, here we show that while nevertheless describing the shifts well up to ∼ 2500 μHz, the linear scaling breaks down conspicuously at higher frequencies. Above this threshold, the shifts follow a power-law dependence with α ∼ 2. Title: Observations of the Sun's Coronal Magnetic Field and Coronal Holes during the Recent Ulysess Second Polar Pass, and Implications for Particle Observations Authors: Sanderson, T. R.; Appourchaux, T.; Hoeksema, J. T.; Harvey, K. L. Bibcode: 2001AGUFMSH32A0723S Altcode: We combine magnetic field observations from the Wilcox Solar Observatory and coronal hole observations from the National Solar Observatory/ Kitt Peak. At solar minimum, the Sun's coronal magnetic field was dipolar and aligned along the spin axis. The current sheet was flat and had very little warp. Around solar maximum, during the second Ulysses southern polar pass, the ratio of quadrupole to dipole strength was high for much of the time. This meant that the current sheet was tilted and highly warped, and reached up to high latitudes. Using the dipole and quadrupole terms from the expansion of the coronal magnetic field, we compute the position of the dipole and quadrupole poles. We find that the location of coronal holes follows the motion of the poles of the magnetic field as the poles move across the surface of the Sun. The polar coronal holes break up into groups of smaller holes all with the same polarity as the poles approach the mid-latitude regions. Surprisingly, there were also times close to solar maximum when the quadrupole/dipole ratio was low, and the current sheet was relatively flat, but still highly inclined. We discuss the implications for the observations of energetic particles at Ulysses. Title: Changes in convective properties over the solar cycle: effect on p-mode damping rates Authors: Houdek, G.; Chaplin, W. J.; Appourchaux, T.; Christensen-Dalsgaard, J.; Däppen, W.; Elsworth, Y.; Gough, D. O.; Isaak, G. R.; New, R.; Rabello-Soares, M. C. Bibcode: 2001MNRAS.327..483H Altcode: Measurements of both solar irradiance and p-mode oscillation frequencies indicate that the structure of the Sun changes with the solar cycle. Balmforth, Gough & Merryfield investigated the effect of symmetrical thermal disturbances on the solar structure and the resulting pulsation frequency changes. They concluded that thermal perturbations alone cannot account for the variations in both irradiance and p-mode frequencies, and that the presence of a magnetic field affecting acoustical propagation is the most likely explanation of the frequency change, in the manner suggested earlier by Gough & Thompson and by Goldreich et al. Numerical simulations of Boussinesq convection in a magnetic field have shown that at high Rayleigh number the magnetic field can modify the preferred horizontal length scale of the convective flow. Here, we investigate the effect of changing the horizontal length scale of convective eddies on the linewidths of the acoustic resonant mode peaks observed in helioseismic power spectra. The turbulent fluxes in these model computations are obtained from a time-dependent, non-local generalization of the mixing-length formalism. The modelled variations are compared with p-mode linewidth changes revealed by the analysis of helioseismic data collected by the Birmingham Solar-Oscillations Network (BiSON); these low-degree (low-l) observations cover the complete falling phase of solar activity cycle 22. The results are also discussed in the light of observations of solar-cycle variations of the horizontal size of granules and with results from 2D simulations by Steffen of convective granules. Title: Effects of a gap-filling method on p-mode parameters Authors: Fierry Fraillon, D.; Appourchaux, T. Bibcode: 2001MNRAS.324.1159F Altcode: The quality of helioseismological ground-based data strongly depends on the presence of a gap in the observational window. In order to address that problem in the case of full-disc low-degree p-mode velocity measurements, Fossat et al. proposed a gap-filling method called `Repetitive music'. The autocorrelation function of the velocity signal shows a correlation of more than 70 per cent at about 4h because of the quasi-periodicity of p-mode peaks in the Fourier spectrum. The method then consists of filling gaps of the velocity signal with data, when they exist, located 4h before or after. By using Monte Carlo simulations, we assess the effects of the gap-filling method on p-mode parameters and their errors. A way to remove the modulation in the power spectrum resulting from the gap-filling method is proposed; its effects on p-mode frequencies, linewidths, amplitudes and asymmetries are discussed as a function of frequency and signal-to-noise ratio. Title: The phenomenology of solar-cycle-induced acoustic eigenfrequency variations: a comparative and complementary analysis of GONG, BiSON and VIRGO/LOI data Authors: Chaplin, W. J.; Appourchaux, T.; Elsworth, Y.; Isaak, G. R.; New, R. Bibcode: 2001MNRAS.324..910C Altcode: We use high-quality helioseismic data collected by three different observational programmes during the declining phase of activity cycle 22,Q7 and a substantial portion of the rising phase of the current cycle (23), to study the phenomenological nature of the cycle-induced (centroid) eigenfrequency variations. We have analysed the frequency dependence of the shifts by fitting a power law of the form δνnl~(νnl)α/Enl to the data (where the Enl are the mode inertias, and α is the power-law index to be extracted). Previous studies have suggested that a relation with α=0 provides an adequate description of the shifts up to ν~3500μHz. However, here we show that while nevertheless describing the shifts well up to ~2500μHz, the linear scaling breaks down conspicuously at higher frequencies. Above this threshold, the shifts follow a power-law dependence with α~2. Our analyses (for 1600<=ν<=4000μHz) make use of observations made by the ground-based GONG over the angular degree range 4<=l<=150 the ground-based BiSON over 0<=l<=2 and the VIRGO/LOI instrument on board the ESA/NASA SOHO satellite over 0<=l<=8. We show that GONG shifts averaged over different ranges in l, together with the BiSON and LOI data averaged over their full quoted ranges, all scale at fixed frequency with the normalized mode inertia ratio QnlQ1. This is to be expected if the solar-cycle perturbation affecting the modes is confined in the surface layers; the excellent agreement also reflects favourably on the external consistency of the different observations. Title: Observing solar-like oscillations with ELODIE spectrograph Authors: Martić, M.; Lebrun, J. C.; Schmitt, J.; Bertaux, J. L.; Appourchaux, T. Bibcode: 2001sf2a.conf..219M Altcode: We have used ELODIE fiber-fed cross-dispersed echelle spectrograph and the 1.93m-telescope of Observatoire de Haute Provence to obtain precise Doppler measurements of a sample of bright stars that are likely to undergo solar-like oscillations. Here we report the results for Procyon from three observing runs (5, 10 and 15 nights) in Decembre 1997, Novembre 1998, and January 1999. The individual frequencies of p-modes were searched in the interval of excess power around 1 mHz found in the frequency spectra of each time series. The echelle diagram of the observed and predicted p-mode frequencies from the standard model (Chaboyer et al., 1999) for Procyon A is presented. We show also some preliminary results for two other solar-like stars (eta Cas and z Her). Title: PICARD: solar diameter measure and g-mode search Authors: Damé, L.; Appourchaux, T.; Berthomieu, G.; Boumier, P.; Cugnet, D.; Gelly, B.; Provost, J.; Toutain, T. Bibcode: 2001ESASP.464..321D Altcode: 2001soho...10..321D The PICARD microsatellite mission will provide 3 to 4 years simultaneous measurements of the solar diameter, differential rotation and solar constant to investigate the nature of their relations and variabilities. The major instrument, SODISM, is a whole Sun imaging telescope of Ø 110 mm which will deliver an absolute measure (better than 4 mas) of the solar diameter and solar shape. Now in Phase B, PICARD is expected to be launched by 2005. We recall the scientific goals linked to the diameter measurement with emphasis on the helioseismology g-mode interest, present the instrument optical concept and present design, and give a brief overview of the program aspects. Title: Observing solar-like oscillations: α CMi, η Cas A and ζ Her A Authors: Martić, M.; Lebrun, J. C.; Schmitt, J.; Appourchaux, T.; Bertaux, J. L. Bibcode: 2001ESASP.464..431M Altcode: 2001soho...10..431M We have used ELODIE fiber-fed cross-dispersed echelle spectrograph and the 1.93m-telescope of Observatoire de Haute Provence to obtain precise Doppler measurements of a sample of bright stars that are likely to undergo solar-like oscillations. Here we report the results for Procyon from three observing runs carried out in December 1997, November 1998, and January 1999. We show also some preliminary results for two other solar-like stars (η Cas A and ζ Her A). Title: Does the excitation and damping of the acoustic eigenmodes vary over the solar cycle? An insight from LOI observations Authors: Chaplin, W. J.; Appourchaux, T. Bibcode: 2001ESASP.464..601C Altcode: 2001soho...10..601C We have used observations made by the LOI instrument on board the ESA/NASA SOHO satellite in order to try and uncover variations in the excitation and damping of the low-angular-degree solar acoustic eigenmodes over the solar cycle. These data were collected on the rising phase of activity cycle 23. We have divided the dataset into independent 136-d and 1-yr time series and fitted the modes in the complex Fourier (frequency) domain to yield estimates of the line widths and amplitudes of the modes. The extracted parameters have then been analyzed in order to search for solar-cycle-induced variations. Over the range 2600 <= ν <= 3600μHz, we uncover a mean implied activity minimum-to-maximum increase in the frequency-domain line widths of 21+/-3 per cent; a mean decrease of 37+/-3 per cent decrease in the mode heights; and a mean decrease of 18+/-4 per cent in the mode powers. Our analysis indicates that - at the level of precision of the available data - the rate at which energy is supplied to the modes remains constant (uncovered variation 3+/-5 per cent). These results are in reasonable agreement with recent claims by Chaplin et al. (2000) and Komm, Howe and Hill (2000) from analyses of BiSON and GONG data respectively. Furthermore, the signs and relative magnitudes of the extracted changes are consistent with the speculation made by Chaplin et al. that it is alterations in the damping, and not the forcing, of the modes that gives rise to the variations observed over the solar activity cycle. Title: Effects of a gap filling method on p-mode parameters Authors: Fierry Fraillon, D.; Appourchaux, T. Bibcode: 2001ESASP.464..347F Altcode: 2001soho...10..347F The quality of helioseismological ground based data strongly depends on the presence of gap in the observational window. In order to address that problem in the case of full disk low p-mode velocity measurements, Fossat et al. (1999) proposed a gap filling method called "Repetitive music". The autocorrelation function of the velocity signal shows a correlation of more than 70% at about 4 hours due to the quasi-periodicity of p-mode peaks in the Fourier spectrum. The method then consists in filling gaps of the velocity signal by data, when they exist, located 4 hours before or after. By using Monte Carlo simulations we assess the effects of the gap filling method on p-mode parameters and their errors. A way to remove the modulation, resulting from the gap-filling method, in the power spectrum is proposed; its effects on p-mode frequencies, linewidths, amplitudes and asymmetries are discussed as a function of both frequency and signal-to-noise ratio of the observational data. Title: Results from the luminosity oscillations imager on board SOHO: low-degree p-mode parameters for a 4-year data set Authors: Appourchaux, T. Bibcode: 2001ESASP.464...71A Altcode: 2001soho...10...71A I report on the results from a 4-year VIRGO/LOI data set. I have analysed independently four 1-year time series mainly for minimizing the effect of solar activity. For l<=3 the p-mode data are fitted using the Fourier spectra taking into account the mode leakage and noise correlations. For l>=4, the data are fitted using simultaneously the power spectra of l=4.7, l=5.8 and l=1.6. The effect of solar activity upon frequencies, linewidths, mode amplitude, energy rate, asymmetry and splitting is studied. Most of these results in intensity confirms earlier measurements made in velocity. Title: Probing the solar cycle: a comparative and complementary analysis of GONG BiSON and VIRGO/LOI eigenfrequency shifts Authors: Chaplin, W. J.; Elsworth, Y.; Isaak, G. R.; New, R.; Appourchaux, T. Bibcode: 2001ESASP.464...83C Altcode: 2001soho...10...83C We use high-quality helioseismic data collected by GONG (over 4 <= l <= 140), BiSON (0 <= l <= 2) and VIRGO/LOI (0 <= l <= 8) to study the phenomenological nature of the cycle-induced (centroid) eigenfrequency variations. We have analyzed the frequency dependence of the shifts by fitting a power-law of the form δνnl ~ (νnl)α/Enl to the data (where the Enl are the mode inertias, and α is the power-law index to be extracted). Previous studies have suggested that a relation with α = 0 provides an adequate description of the shifts up to ν ≍ 3500 μHz. However, here we show that while nevertheless describing the shifts well up to ~2500 μHz, the linear scaling breaks down conspicuously at higher frequencies. Above this threshold, the shifts follow a power-law dependence with α ~ 2. We also ahow that GONG shifts, averaged over different ranges in l together with the BiSON and LOI data averaged over their full quoted ranges, all scale at fixed frequency with the normalized mode inertia ratio Qnl (Christensen-Dalsgaard & Berthomieu 1991). This is to be expected if the solar-cycle perturbation affecting the modes is confined in the surface layers; the excellent agreement also reflects favourably on the external consistency of the different observations. Title: Dependence on azimuthal order of the amplitudes of low-degree p modes Authors: Fröhlich, C.; Appourchaux, T.; Gough, D. O. Bibcode: 2001ESASP.464..629F Altcode: 2001soho...10..629F The m-dependence of the amplitudes of the multiplets of low-degree p modes contains information about the latitudinal distribution of the power in the excitation of the oscillations. We present estimates of those amplitudes from 4 years of VIRGO/LOI observations. Variation of the excitation with magnetic activity is studied. Title: g-mode detection: Where do we stand? Authors: Appourchaux, T.; Andersen, B.; Berthomieu, G.; Chaplin, W.; Elsworth, Y.; Finsterle, W.; Frölich, C.; Gough, D. O.; Hoeksema, T.; Isaak, G.; Kosovichev, A.; Provost, J.; Scherrer, P.; Sekii, T.; Toutain, T. Bibcode: 2001ESASP.464..467A Altcode: 2001soho...10..467A We review the recent developments in determining the upper limits to g-mode amplitudes obtained by SOHO instruments, GONG and BiSON. We address how this limit can be improved by way of new helioseismic instruments and/or new collaborations, hopefully providing in the not too distant future unambiguous g-mode detection. Title: On measuring low-degree p-mode frequency splitting with full-disc integrated data Authors: Appourchaux, T.; Chang, H. -Y.; Gough, D. O.; Sekii, T. Bibcode: 2000MNRAS.319..365A Altcode: The standard method of measuring rotational splitting from solar full-disc oscillation data, based on maximum-likelihood fitting of multi-Lorentzian profiles to oscillation power spectra, systematically overestimates the splitting. One of the reasons is that the maximum likelihood estimators (MLE) become unbiased only asymptotically as the number of data tends to infinity; for a finite data set they are often biased, inducing a systematic error. In this paper we assess by Monte Carlo simulations the amount of systematic error in the splitting measurement, using artificially generated power spectra. The simulations are carried out for multiplets of degree S(t) = ΣkSk(t), l=1, 2 and 3 with various signal-to-noise ratios, linewidths and observing times. We address the possible use of non-MLE estimators that could provide a smaller or negligible systematic error. The implication for asteroseismology is also discussed. Title: Observational Upper Limits to Low-Degree Solar g-Modes Authors: Appourchaux, T.; Fröhlich, C.; Andersen, B.; Berthomieu, G.; Chaplin, W. J.; Elsworth, Y.; Finsterle, W.; Gough, D. O.; Hoeksema, J. T.; Isaak, G. R.; Kosovichev, A. G.; Provost, J.; Scherrer, P. H.; Sekii, T.; Toutain, T. Bibcode: 2000ApJ...538..401A Altcode: Observations made by the Michelson Doppler Imager (MDI) and Variability of solar IRradiance and Gravity Oscillations (VIRGO) on the Solar and Heliospheric Observatory (SOHO) and by the ground-based Birmingham Solar Oscillations Network (BiSON) and Global Oscillations Network Group (GONG) have been used in a concerted effort to search for solar gravity oscillations. All spectra are dominated by solar noise in the frequency region from 100 to 1000 μHz, where g-modes are expected to be found. Several methods have been used in an effort to extract any g-mode signal present. These include (1) the correlation of data-both full-disk and imaged (with different spatial-mask properties)-collected over different time intervals from the same instrument, (2) the correlation of near-contemporaneous data from different instruments, and (3) the extraction-through the application of complex filtering techniques-of the coherent part of data collected at different heights in the solar atmosphere. The detection limit is set by the loss of coherence caused by the temporal evolution and the motion (e.g., rotation) of superficial structures. Although we cannot identify any g-mode signature, we have nevertheless set a firm upper limit to the amplitudes of the modes: at 200 μHz, they are below 10 mm s-1 in velocity, and below 0.5 parts per million in intensity. The velocity limit corresponds very approximately to a peak-to-peak vertical displacement of δR/Rsolar=2.3×10-8 at the solar surface. These levels which are much lower than prior claims, are consistent with theoretical predictions. Title: Source of excitation of low-l solar p modes: characteristics and solar-cycle variations Authors: Chaplin, W. J.; Appourchaux, T.; Elsworth, Y.; Isaak, G. R.; Miller, B. A.; New, R. Bibcode: 2000MNRAS.314...75C Altcode: We investigate various properties of the excitation source that is responsible for driving the acoustic p-mode oscillations of the Sun. Current prejudice places this in the superadiabatic layer of the convection zone. We consider in detail how the precise nature of the resonant mode spectrum is modified: (i) as a result of the impact of different source-multipole mixtures; and (ii) as a function of the radial extent of the source. To do this, we model the observed resonant spectra with the solutions to a simple, one-dimensional wave equation which is intended to describe the essential elements of the solar resonant acoustic cavity. Further, we also fit these models to the low-l peaks in a high-resolution power spectrum generated from data collected by the Birmingham Solar-Oscillations Network (BiSON). We also use the extensive BiSON data set to search for variations in the source characteristics over the solar cycle. Title: COROT -- A Unique Database for Low Amplitude Variability Between 1 Minute and 150 Days Authors: Michel, E.; Baglin, A.; Barge, P.; Catala, C.; Auvergne, M.; Weiss, W. W.; Appourchaux, T.; Garrido, R.; COROT Team Bibcode: 2000ASPC..203...69M Altcode: 2000ilss.conf...69M; 2000IAUCo.176...69M COROT is a high precision wide field photometry experiment from space, funded in the framework of the CNES ``Petites Missions'' program (the PI is A. Baglin). It will observe approximately 30000 objects with mV between 4.5 and 15.5 over long observational periods (up to 150 d), with a time sampling between 1 s and 16 min, a precision of the order of 10-4 per measurement. The scientific objectives are stellar seismology and the search for telluric planets. The instrument and the core program have already been presented in several places. We here focus on a description of the characteristics of the data to be obtained with COROT. The large amount of high quality data collected by COROT will constitute rich material for several research programs beyond the core program as already defined (http://www.astrsp-mrs.fr/www/corot.html). A call for proposal of additional programs will be made during Northern Spring 2000. Title: I-V phase difference and gain analysis of GONG full-disk data Authors: Oliviero, M.; Severino, G.; Straus, T.; Jefferies, S. M.; Appourchaux, T. Bibcode: 2000MmSAI..71..999O Altcode: No abstract at ADS Title: Depth of excitation and reversal of asymmetry of low-l solar P modes: a complementary analysis of BiSON* and VIRGO/SPM† data Authors: Chaplin, W. J.; Appourchaux, T. Bibcode: 1999MNRAS.309..761C Altcode: We use the solutions to a simple, one-dimensional wave equation - which is intended to describe the essential elements of the solar resonant acoustic cavity - as formalistic models to which to fit low-l modes in observational helioseismic power spectra. We have analysed data collected in velocity, by the ground-based Birmingham Solar-Oscillations Network (BiSON), and in intensity, by the full-disc VIRGO Sun photometers (SPM) on board the ESA/NASA SOHO satellite. Our analysis extracts, as a function of the modal radial overtone number n, direct estimates of: the location of the excitation source of the acoustic resonances; and the size of the component of the convective granulation that is correlated to the observations of the resonances, and is responsible for the reversal of asymmetry of the mode profiles when different observation techniques are applied (i.e. intensity or Doppler velocity measurements). This information is coded in the complicated forms of the observed, resonant profiles. Title: Evidence for global pressure oscillations on Procyon Authors: Martić, M.; Schmitt, J.; Lebrun, J. -C.; Barban, C.; Connes, P.; Bouchy, F.; Michel, E.; Baglin, A.; Appourchaux, T.; Bertaux, J. -L. Bibcode: 1999A&A...351..993M Altcode: Precise Doppler measurements of the star Procyon (alpha CMi, HR 2943) have been obtained with the ELODIE fiber-fed cross-dispersed echelle spectrograph on the 1.93 m telescope at Observatoire de Haute Provence. Here, we present the analysis of data from 10 days observing run carried out in November 1998. We detect significant excess in the power between 0.5-1.5 mHz in the periodograms of the time series of mean Doppler shifts. Observations of eta Cas made with the same instrument during the same time interval and in almost identical night conditions show a flat spectrum in this frequency range, indicating that the excess of Doppler signal seen on Procyon is of stellar origin. When data from the whole run are jointly analyzed, a period analysis places an upper limit of 0.50-0.60 ms-1 for the amplitude of oscillations, while the frequency cutoff is around 1.5 mHz. The power evidently drops near 0.55 and 1.5 mHz on the average of unfiltered power spectra of individual nights, which is consistent with the expected p-mode oscillation properties for Procyon. Several equispaced peaks in frequency are recurrent in the power spectra of two independent segments of 4 and 3 contiguous nights; the most probable frequency spacing seems to be 55 mu Hz. In conclusion, we now have an instrument set-up which is sufficiently stable and fast to be used for a multi-site campaign involving instruments with comparable velocity precisions, to detect the oscillation modes of sun-like stars. Based on observations obtained at the Observatoire de Haute-Provence (CNRS, France) Title: Solar low-degree p-mode parameters from the GONG network Authors: Rabello-Soares, M. C.; Appourchaux, T. Bibcode: 1999A&A...345.1027R Altcode: Low-degree solar p modes observed by the GONG network have been analysed for l <= 6, yielding accurate measurements of their frequencies, splittings and linewidths. The results obtained here show significant improvement on previous determinations, especially for increasing the number of identified modes with l <= 3 and for minimizing the bias on the splitting determination and the error bars. A more realistic approach was used to fit the helioseismic data assuming that the observed spectra are statistically dependent upon one another. This is in contrast to what is commonly done and the result is a better treatment of the leakage between the modes. Moreover, the effect of an imperfect knowledge of the leakage within the elements of the l=1 multiplets upon their splitting determination is analysed. In addition, the effect of the leakage between the modes of different degrees upon the p-mode parameters determination is shown, and a procedure for `cleaning' the spatial alias is described leading to splitting coefficients with smaller systematic errors than before. Title: Space and Time Analysis of the Solar Photospheric Dynamics at Moderate-l Values Authors: Oliviero, M.; Severino, G.; Straus, Th.; Jefferies, S. M.; Appourchaux, T. Bibcode: 1999ApJ...516L..45O Altcode: A space-time analysis of 36 days' worth of full-disk intensity and velocity images, obtained by the Global Oscillation Network Group, is used to produce a high-resolution l-ν phase-difference spectrum for the spectral range (4<=l<=2000, 0<=ν<=8.3 mHz). This is the first time a phase-difference spectrum has been produced for intermediate-l values. The phase differences on the p-mode ridges are found to linearly increase from ~65° at 2 mHz up to ~95° at 4.7 mHz. Only near 3.9 mHz are the differences close to 90°, the theoretically expected phase for adiabatic evanescent waves. The phases between the ridges exhibit a steplike behavior in frequency with negative values at low frequency and positive values (greater than 90°) at high frequency. The negative phase values are consistent with the extension to low- and moderate-l values of the plateau-interridge regime discovered by Deubner et al. in 1990. However, positive phase values, which represent higher phase for the solar background than for the acoustic modes, were not expected. An understanding of this observed phase-difference behavior will improve our knowledge of the nature of the solar background and its interaction with the acoustic p-modes. Title: PICARD: simultaneous measurements of the solar diameter, differential rotation, solar constant and their variations Authors: Damé, Luc; Hersé, Michel; Thuillier, Gérard; Appourchaux, Thierry; Crommelynck, Dominique; Dewitte, Steven; Joukoff, Alexandre; Fröhlich, Claus; Laclare, Francis; Delmas, Christian; Boumier, Patrick Bibcode: 1999AdSpR..24..205D Altcode: PICARD is a CNES micro-satellite mission due for flight by the end of 2002, named after the name of a French astronomer who first observed with consistency the solar diameter changes during the Maunder minimum in the 16th century. It consists of two instruments measuring (i) the solar diameter and differential rotation, and (ii) the total solar irradiance. These quantities are fundamental for the understanding of the solar-Terrestrial relations, e.g. the influence of the Sun on the Earth's climate, and of the internal structure of the Sun. The continuous - or nearly continuous - viewing of the Sun from an appropriate orbit, the 5 minutes sampling rate and the very low noise measurements, will allow g-modes detection and precise diameter measurements besides accurately establishing the relationship between irradiance and diameter changes. Providing an absolute measure of the solar diameter to 1 milliarcsecond, PICARD is the first step towards instruments capable of accurate and perennial measurements, for the centuries to come, of the solar-terrestrial influence. The objectives of the mission, instrument capabilities, observing modes and performances are described. Title: The art of fitting p-mode spectra. II. Leakage and noise covariance matrices Authors: Appourchaux, T.; Rabello-Soares, M. -C.; Gizon, L. Bibcode: 1998A&AS..132..121A Altcode: 1997astro.ph.10131A In Part I we have developed a theory for fitting p-mode Fourier spectra assuming that these spectra have a multi-normal distribution. We showed, using Monte-Carlo simulations, how one can obtain p-mode parameters using ``Maximum Likelihood Estimators". In this article, hereafter Part II, we show how to use the theory developed in Part I for fitting real data. We introduce 4 new diagnostics in helioseismology: the (m,nu ) echelle diagram, the cross echelle diagram, the inter echelle diagram, and the cross spectrum ratio. These diagnostics are extremely powerful to visualize and understand the covariance matrices of the Fourier spectra, and also to find bugs in the data analysis code. The diagrams are used to verify the computation of the leakage matrices, and also to measure quantitatively these matrices. Cross spectrum ratios are used to obtain quantitative information on the noise covariance matrices. Numerous examples using the LOI/SOHO and GONG data are given. Title: The art of fitting p-mode spectra. I. Maximum likelihood estimation Authors: Appourchaux, T.; Gizon, L.; Rabello-Soares, M. -C. Bibcode: 1998A&AS..132..107A Altcode: 1997astro.ph.10082A In this article we present our state of the art of fitting helioseismic p-mode spectra. We give a step by step recipe for fitting the spectra: statistics of the spectra both for spatially unresolved and resolved data, the use of Maximum Likelihood estimates, the statistics of the p-mode parameters, the use of Monte-Carlo simulation and the significance of fitted parameters. The recipe is applied to synthetic low-resolution data, similar to those of the LOI, using Monte-Carlo simulations. For such spatially resolved data, the statistics of the Fourier spectrum is assumed to be a multi-normal distribution; the statistics of the power spectrum is not a chi (2) with 2 degrees of freedom. Results for l=1 shows that all parameters describing the p modes can be obtained with negligible bias and with minimum variance provided that the leakage matrix is known. Systematic errors due to an imperfect knowledge of the leakage matrix are derived for all the p-mode parameters. Title: Asymmetry and Frequencies of Low-Degree p-Modes and the Structure of the Sun's Core Authors: Toutain, T.; Appourchaux, T.; Fröhlich, C.; Kosovichev, A. G.; Nigam, R.; Scherrer, P. H. Bibcode: 1998ApJ...506L.147T Altcode: An accurate determination of the frequencies of low-degree solar p-modes is an important task of helioseismology. Using 679 days of solar oscillation data observed in Doppler velocity and continuum intensity from two Solar and Heliospheric Observatory instruments (the Michelson Doppler Imager and the SunPhotoMeter), we show that fitting the spectra with Lorentzian profiles leads to systematic differences between intensity and velocity frequencies as large as 0.1 μHz for angular degrees l=0, 1, and 2 because of the opposite asymmetry between intensity and velocity. We use a physics-based asymmetrical line shape to fit p-mode lines, and we demonstrate that their asymmetry is statistically significant and that frequency differences are considerably reduced. These measurements provide more accurate estimates of the solar eigenfrequencies. We discuss inferences of the structure of the solar core. Title: Results from the Luminosity Oscillations Imager on board SOHO: Low-degree p-mode Parameters for a 2-year Data Set Authors: Appourchaux, T.; Virgo Team Bibcode: 1998ESASP.418...99A Altcode: 1998soho....6...99A I will report on the results from a 2-year LOI time series starting on March 27, 1995 and ending on March 26, 1998. From the data set, I have analysed independently two 1-year time series mainly for minimizing the effect of solar activity. For l < 3 the p-mode data are fitted using the Fourier spectra taking into account the mode leakage and noise correlations (Appourchaux et al, 1998; Schou, 1992). For 4 < l < 9, the small number of pixels (12) lead to undersampling that result into non-inversible leakage matrices: the Fourier spectra cannot be utilised anymore (Appourchaux et al, 1998). In addition for these degrees, the spectra of the l = 4,5 modes are strongly polluted by the l = 7,8 modes, and vice versa. Due to these two major problems, I have fitted simultaneously the power spectra of l = 4,7 and l = 5,8; this is clearly an approximation that will lead to systematic errors. I will give tables of frequencies, splittings and linewidths for the 2-year data set. The splittings are compared with other data sets such as LOWL, MDI and GONG. The effects of the solar activity is also studied. Title: The art of fitting p-mode spectra Authors: Appourchaux, T.; Gizon, L. Bibcode: 1998IAUS..185...43A Altcode: We describe how to extract the p-mode parameters from complex Fourier spectra using maximum likelihood estimators. We expect our description to be quite general and didactic. We discuss problems such as the choice of the optimal filters and the construction of the leakage and covariance matrices. The LOI/SOHO Team makes use of these methods. Title: Sources of Amplitude Modulation of Solar P-Modes Authors: Leifsen, Torben; Andersen, Bo; Appourchaux, Thierry Bibcode: 1998ESASP.418..939L Altcode: 1998soho....6..939L We study the amplitude variation with time of the solar radial p-modes. Continuous datasets from more than two years of observations with the SOHO/VIRGO SPM and LOI instruments were used. A Hilbert transform method was used to study the time variation of the amplitudes of the l = 0-3 modes with radial order 12-32. The observed amplitudes of the modes vary substantially with time on a large range of timescales up to more than a solar rotation. As expected the power spectra of the amplitude variation show little or no consistent periodicities for most of the modes. However, for some of the modes, specifically for it l = 0, n = 21 and 22, a strong modulation is observed with the solar sidereal rotation frequency. This is a very surprising result as the {l} = 0 modes should be insensitive to the solar rotation. In contrast the SPM blue channel irradiance observations show a modulation with the solar synodic rotation frequency. This is as one would expect as active regions rotate over the solar disc and thereby modulate the irradiance signal. A comparison with MDI velocity data show that the amplitude modulation of the modes closely resembles the modulation as observed with VIRGO/SPM. This shows that the observed modulation is not an effect of the irradiance variation due to active regions, but rather a modulation of the mode itself by rotation. This conclusion is strengthened by the fact that the symmetric {l} = 0 modes are modulated by the sidereal and not the synodic rotation frequency. The two years of observations cover times of both low and higher solar activity as the activity of the new solar cycle started in the summer of 1997. In the solar irradiance one can see the onset of the new solar cycle as a frequency shift to lower frequencies as the activity appear at higher solar latitudes. Surprisingly a similar shift is also seen in the modulation of the two modes, indicating that the modulation of the modes is closely connected to the latitudes of solar activity. Title: Line Asymmetry of VIRGO and MDI Low-Degree p Modes Authors: Toutain, T.; Appourchaux, T.; Frohlich, C.; Kosovichev, A.; Rakesh, N.; Scherrer, P. Bibcode: 1998ESASP.418..973T Altcode: 1998soho....6..973T Using continuous time series of 610 days of velocity (MDI, LOI-proxy) and intensity (VIRGO, SPM and LOI) we show that Lorentzian profiles as a model of low-degree p-mode line leads to systematic differences in the determination of intensity and velocity mode frequencies. These differences, as large as 0.1 muHz for degrees l = 0, 1, 2 and 3, are frequency-dependent. The use of a physics-based asymmetrical line shape (Rakesh et al., 1998) to fit the same lines has allowed us to significantly reduce differences in the frequency determination. P-mode lines in velocity exhibit a significant negative asymmetry (excess of power in the left wing) whereas p-modes lines in intensity have a positive asymmetry (excess of power in the right wing). The magnitude and sign of this asymmetry are directly related to the location of the source of p-mode excitation and to the correlation between mode and solar noise. Title: Rotation of the Solar Core Inferred from GONG Data Authors: Rabello-Soares, M. C.; Appourchaux, T.; Christensen-Dalsgaard, J. Bibcode: 1998ESASP.418..837R Altcode: 1998soho....6..837R We present inferences of the solar core rotation derived from GONG frequency splittings. The GONG data for the low-degree modes (l <= 6) are for the one year period Aug. 1995-1996; these splittings were determined using a new method of fitting heliosismic spectra (Rabello-Soares & Appourchaux 1998). These are combined with GONG data for higher degree modes, as obtained by the GONG team (Hill et al. 1996). We have employed a new two-dimensional implementation of the optimally localized averages (OLA) inversion method (Chaplin et al. 1998). As in one dimension, the OLA produces better-localized averaging kernels than do least-squares techniques. This is particularly beneficial in the deep interior, where it is in any case difficult to obtain localized information. Title: Time Dependence of Solar Noise Observed with VIRGO Authors: Andersen, Bo; Leifsen, Torben; Appourchaux, Thierry; Frohlich, Claus; Jiménez, Antonio; Wehrli, Christoph Bibcode: 1998ESASP.418...83A Altcode: 1998soho....6...83A The effect of non- and quasiperiodic solar surface structures dominate the power spectra of solar irradiance and radiance over a broad range of time scales. Only in the p-mode region above about 2 mHz and in the rotationally dominated region below about 3 μ Hz there seems to be narrow stationary peaks. The solar background signal, or solar noise has clear large scale quasi-stationary structures that seems to be closely correlated to the combination of timescales and contrasts of the solar surface sources. The dominant sources are the solar granulation and supergranulation. The solar noise determines the detection limit in the search for g-modes. Thus an increased understanding of it may be helpfull in this search. In addition this understanding will be usefull to determine the properities of stellar small scale surface structures from the data from future asteroseismology space missions. In this study we use the VIRGO data to study the time variation of the solar noise with timescales from about one day to about one year. Title: Statistical Properties of the Amplitude Modulation of Solar p-Modes Authors: Andersen, Bo; Aarset, Magne; Leifsen, Torben; Appourchaux, Thierry; Frohlich, Claus; Hoeksema, J. T.; Jiménez, Antonio; Toutain, Thierry Bibcode: 1998ESASP.418..897A Altcode: 1998soho....6..897A The low degree solar p-modes show amplitude modulation at all observable timescales. For some modes a large fraction of this modulation seems to be correlated to the solar rotation. For other modes there seems to be little or no deterministic component in the modulation. Only intermittent correlation between the modulation of different modes have been observed. This is to be expected if the excitation of modes is completely stochastic. None of the observational methods observe the modes directly. In different ways they all observe the solar atmospheres response to the modes. This implies that the modes may be modulated by this response. By studying the statistical properties of the different observed modes we attempt to discriminate between variations in the modes themselves and the atmospheric response. In this work we study the statistical properties of the mode amplitude variations for radial order p-modes observed with the VIRGO and SOI/MDI instruments on SOHO. The time scales studied span the region from 0.2 μ Hz to 15 muHz. Here, we are modelling the amplitude modulation, utilising the concepts of state space models, as a stochastic process and study the properties of this model as function of radial order and line width of the modes. Title: Observations of the latitudinal variation of the solar radiance of non-active regions of the sun. Authors: Domingo, V.; Sanchez, L.; Appourchaux, T.; Andersen, B. Bibcode: 1998IAUS..185..111D Altcode: The Luminosity Oscillations Imager (LOI) of the VIRGO experiment aboard SOHO provides continuous measurement of the solar irradiance in a 5 nm band around 500 nm. The solar image is broken down in 12 pixels distributed in 4 latitudinal bands. The first year of operation of the instrument has taken place during a period of solar minimum activity. The measurements provide an indication of the distribution of the solar irradiance variations versus latitude. Contributions to the observed variations due to the presence of active regions are discussed in relation to the possible effect of the evolving solar cycle (structure of the convection zone): short term variations versus long term variations. The problem of the photometric stability of the measurements needed for the investigation is thoroughly treated by self consistency and by comparison with other instruments on SOHO (VIRGO sun- photometers and MDI intensity measurements). Title: LOI low-degree rotational splittings Authors: Appourchaux, T.; Rabello Soares, M. C.; Gizon, L. Bibcode: 1998IAUS..185..167A Altcode: We present measurements of rotational splitting frequencies of low-degree p-modes. The data which have been analyzed correspond to one-year spatially resolved observations obtained with the Luminosity Oscillation Imager onboard the SOHO spacecraft. Title: Observational Upper Limits for Low-Degree Solar g-modes Authors: Fröhlich, C.; Finsterle, W.; Andersen, B.; Appourchaux, T.; Chaplin, W. J.; Elsworth, Y.; D. O. Gough; Hoeksema, J. T.; Isaak, G. R.; Kosovichev, A. G.; Provost, J.; Scherrer, P. H.; Sekii, T.; Toutain, T. Bibcode: 1998ESASP.418...67F Altcode: 1998soho....6...67F No abstract at ADS Title: Amplitude modulation of radial p-modes from Virgo Authors: Leifsen, T.; Andersen, B. N.; Appourchaux, T.; Frohlich, C.; Jimenez, A.; Toutain, T.; Wehrli, C. Bibcode: 1998IAUS..185..113L Altcode: We present results from wavelet analysis of more than one year of data from the VIRGO Sun Photometers (SPM) and the VIRGO Luminosity Oscillation Imager (LOI) onboard the SOHO spacecraft. The temporal behaviour of p-modes with l=0--2 is presented. The analysis of the l=0 modes show a modulation of the mode amplitudes with the solar rotation. This result is quite surprising as the l=0 modes should not be sensitive to the solar rotation. Possible effects of varying solar activity on the modulation of the mode amplitudes is investigated. The effect of the modulation on the fitting of mode lines and determination of the mode frequencies is also studied. Wavelet analysis has a fundamental limitation in the ability to achieve simultaneous high frequency and time resolution. In order to be able to study the rotationally split components of the l=1 modes with good time resolution, we apply a spatial filtering technique on the LOI data to separate the different components. Title: A comparison of low-degree solar p-mode frquencies from BISON and LOI Authors: Appourchaux, T.; Chaplin, W. J.; Elsworth, Y.; Isaak, G. R.; McLeod, C. P.; Miller, B. A.; New, R. Bibcode: 1998IAUS..185...45A Altcode: Here, we compare the low-degree solar p-mode frequencies returned from the analysis of two, contemporaneous, independent helioseismological data sets collected during 1996. The first comprises Doppler velocity observations of the 770-nm line of potassium, made in integrated sunlight by the six-station, terrestrial Birmingham Solar-Oscillations Network (BiSON). The second consists of irradiance distribution measurements of the solar disc, made at 500rm nm, by the Luminosity Oscillations Imager (LOI), which is part of the VIRGO experiment on the ESA/NASA SOHO satellite. Title: LOI/SOHO constraints on oblique rotation of the solar core Authors: Gizon, L.; Appourchaux, T.; Gough, D. O. Bibcode: 1998IAUS..185...37G Altcode: The Sun is usually assumed to rotate about a single axis, tilted with respect to the ecliptic normal by an angle of 7.25 degrees. Although we have an excellent knowledge of the direction of the rotation axis of the photospheric layers, we cannot exclude a priori that the direction of the rotation axis could vary as a function of radius. We have tried to check whether the assumption of rotation about a unique axis is consistent with helioseismic data. We report on an attempt to measure the directions of the pulsation axes of several low-degree modes of oscillation in the LOI/SOHO Fourier spectra. Title: The Structure of the Solar Core: an Observer's Point of View Authors: Appourchaux, T. Bibcode: 1998ESASP.418...37A Altcode: 1998soho....6...37A Since the beginning of helioseismology, most of the internal and dynamics structure of the Sun has been revealed or so we thought. The last island where our powerful tools start to fail is the solar core, where nuclear reactions take place. With the advent of SOHO and GONG, we have now a quality of helioseismic data without precedence that should enable us to understand better the physics of the deepest solar regions. This goal can be partially achieved by measuring low-degree rotational splitting of p-modes, and by detecting the elusive g-modes. In a first part, I will review the fitting techniques that are being used for inferring the rotational splittings of low-degree p-modes. I will particularly focus on Fourier spectra fitting developped by Schou (1992) and refined by Appourchaux et al (1998). I will show how one can visualize from the data, the leakage matrix and how one can clean the data from the mode leakages. I will give examples of systematic errors introduced by the leakage matrix and by modes of aliasing degrees. I will also compare the Fourier spectra fitting technique to others techniques that use power spectra. I will give some recent results from SOHO and GONG. In a second part, I will report on the progress of the Phoebus group for detecting g-modes. The Phoebus group is composed of team members of BiSON, VIRGO and SOI/MDI. I will summarize some of the techniques we used for finding g-modes, and how one can use those for finding low-order low-frequency p-modes. I will, most probably, not report on g-mode detection but most likely stress that the future ahead of us is brighter than ever. Title: Comparative Studies of Low-Order and Low-Degree Solar p Modes Authors: Appourchaux, T.; Andersen, B.; Chaplin, W.; Elsworth, Y.; Finsterle, W.; Frohlich, C.; Gough, D.; Hoeksema, J. T.; Isaak, G.; Kosovichev, A.; Provost, J.; Scherrer, P.; Sekii, T.; Toutain, T. Bibcode: 1998ESASP.418...95A Altcode: 1998soho....6...95A The amplitudes of solar p-modes decrease steeply with decreasing radial order below about 17. The background solar signal (solar noise) in general increases steadily with decreasing frequency. For the irradiance and radiance measurements with VIRGO or SOI/MDI on SOHO this combination makes it difficult to detect low degree modes below about 1.8 mHz. The solar noise as observed in velocity with SOI/MDI or the ground based BISON network is significantly lower in this region than in intensity measurements. This allows low degree modes to be observed close to 1 mHz. We present results of detection and charaterization of the lowest order observable p-modes both in velocity and intensity measurements. Where applicable the properties of the modes observed with the two methods are compared. Title: The Effect of Amplitude Modulation on Asymmetries of Solar p-Modes Authors: Andersen, Bo; Leifsen, Torben; Appourchaux, Thierry; Frohlich, Claus; Hoeksema, J. T.; Toutain, Thierry Bibcode: 1998ESASP.418..893A Altcode: 1998soho....6..893A The low degree solar p-modes show an asymmetry in their line profiles that both depend on the observational technique and on the radial order of the modes. Typically the modes determined from observations with Doppler shift methods show an asymmetry towards lower frequency while the opposite is the case for modes determined from irradiance and radiance observations. The difference in asymmetry is probably caused by near surface effects. If the modes are fitted with symmetric functions this leads to a systematic shift in the frequency determinations for the two data sets. This may lead to systematic differences in the inversions based on the different frequencies. All the mode amplitudes show significant time variation. The typical centroid frequency also varies with timescales from a few days to the solar cycle. These variations may set absolute limits to the observable accuracy of the frequency determination. These time modulations may influence the observed line profiles and thus the frequency determinations. Here we present results of the effect on the mode asymmetry of the amplitude modulation of low degree modes observed with VIRGO and SOI/MDI. The range in timescales is from a few days to a few solar rotations. Title: Measurement of GONG Low-Degree p-Mode Parameters Authors: Rabello-Soares, M. C.; Appourchaux, T. Bibcode: 1998ESASP.418..299R Altcode: 1998soho....6..299R Low-degree solar p modes observed by the GONG network have been analysed for ell <= 6 yielding accurate measurements of their frequencies, splittings and linewidths. The results obtained show significant improvement over the GONG project parameters especially for minimizing the bias on the splitting and the error bars. We used a new method of fitting helioseismic spectra where, instead of fitting the power spectra, we fitted the Fourier spectra involving the knowledge of the mode leakage matrix. The effect of an imperfect knowledge of the ell = 1 leakage matrix upon the splitting determination is shown both for power spectra and Fourier spectra fitting. In addition, the effect of the leakage between the modes of different degrees, or spatial alias, upon the splitting coefficient is analysed. A procedure for cleaning the spatial alias is described leading to splitting coefficients with smaller systematic errors than before. Title: On the Effect of Active Regions on the Solar Irradiance Authors: Domingo, V.; Sanchez, L.; Appourchaux, T.; Fröhlich, C.; Wehrli, C.; Crommelynck, D.; Pap, J. Bibcode: 1997ESASP.415..469D Altcode: 1997cpsh.conf..469D No abstract at ADS Title: Successful Recovery from LOI Cover In-Orbit Anomaly on SOHO Authors: Yorck, M.; Appourchaux, T.; Eiden, M. Bibcode: 1997ESASP.410..215Y Altcode: 1997smt..conf..215Y No abstract at ADS Title: Tri-Phonic Helioseismology: Comparison of Solar P Modes Observed by the Helioseismology Instruments Aboard SOHO Authors: Toutain, T.; Appourchaux, T.; Baudin, F.; Fröhlich, C.; Gabriel, A.; Scherrer, P.; Andersen, B. N.; Bogart, R.; Bush, R.; Finsterle, W.; García, R. A.; Grec, G.; Henney, C. J.; Hoeksema, J. T.; Jiménez, A.; Kosovichev, A.; Roca Cortés, T.; Turck-Chièze, S.; Ulrich, R.; Wehrli, C. Bibcode: 1997SoPh..175..311T Altcode: The three helioseismology instruments aboard SOHO observe solar p modes in velocity (GOLF and MDI) and in intensity (VIRGO and MDI). Time series of two months duration are compared and confirm that the instruments indeed observe the same Sun to a high degree of precision. Power spectra of 108 days are compared showing systematic differences between mode frequencies measured in intensity and in velocity. Data coverage exceeds 97% for all the instruments during this interval. The weighted mean differences (V-I) are −0.1 µHz for l=0, and −0.16 µHz for l=1. The source of this systematic difference may be due to an asymmetry effect that is stronger for modes seen in intensity. Wavelet analysis is also used to compare the shape of the forcing functions. In these data sets nearly all of the variations in mode amplitude are of solar origin. Some implications for structure inversions are discussed. Title: On the direction of the rotation axis of the Sun Authors: Gizon, L.; Appourchaux, T. Bibcode: 1997BAAS...29R1121G Altcode: No abstract at ADS Title: Contribution of Low-l p Modes to the Solar Equatorial Rotation Profile Authors: Rabello Soares, M. C.; Roca Cortés, T.; Jiménez, A.; Appourchaux, T.; Eff-Darwich, A. Bibcode: 1997ApJ...480..840R Altcode: The solar equatorial velocity profile is known down to the base of the convection zone with high precision (<=1%) from here downward until approximately 0.5 R⊙, it seems to be constant, independent of latitude, and lower than the equatorial surface rate. This result comes from the inversion of high-l p-mode observations (Thompson et al. 1996), while low-l p modes, which penetrate deeper, are not measured to the precision required. Recently, new results from the LOWL instrument on such modes suggest that deeper down, the rotation rate could be even slower (Tomczyk, Schou, & Thompson 1995a). Here results from LOI-T, a low-resolution high-precision photometer, are presented and analyzed to yield accurate measurements of the frequencies and splittings of modes with 2 <= l <= 8. The accuracy of the frequency determinations and the agreement with the best results yielded by low- and high-l instruments give credit to the results and show its capability as an intercalibrating tool for experiment. The splittings found, combined with those of GONG (high-l modes), are used to perform an inversion of the equatorial rotation profile in the radiative interior; the result found is that the region from 0.2 <= r/R⊙ <= 0.4 rotates slower than the surface rate. Title: Study of the Effect of Active Regions on the Solar Irradiance During Solar Minimum Authors: Domingo, V.; Sanchez, L.; Appourchaux, T.; Froehlich, C.; Wehrli, C.; Hoeksema, T.; Pap, J. Bibcode: 1997SPD....28.0206D Altcode: 1997BAAS...29..893D We have determined both the size of the area that contributes to the solar irradiance increase around an active region and the angular distribution of the radiance excess in it, using data obtained during about one year around solar minimum (April 1996 - April 1997). During the solar minimum and the early raising phase of the new maximum it is possible to study the effect of isolated active regions while there are few of them. The result of this study will be important to separate the contribution of the active regions to the solar irradiance change during the solar cycle from any underlying long term effect, if there is one. The solar radiance measured by the Low-resolution Oscillations Imager (LOI) of the VIRGO instrument and by the MDI instrument aboard SOHO is used to determine the dimension of the radiating area. The increase in irradance is determined by the Sun Photometers (SPM) and Radiometers on the VIRGO instrument. Title: The Effects of Systematic Errors in the Estimation of p-Mode Frequencies on the Inversion of Solar Internal Structure Authors: Rhodes, E. J., Jr.; Appourchaux, T.; Bachmann, K.; Kosovichev, A. G.; Scherrer, P. H.; Schou, J.; Reiter, J. Bibcode: 1997SPD....28.0901R Altcode: 1997BAAS...29..913R The frequencies and associated uncertainties of the low-, intermdeiate-, and high-degree p-mode oscillations are the input quantities for the inversion programs which infer the thermodynamic structure of the solar interior. In this review we will attempt to demonstrate the different possible systematic errors that are currently present in our estimation of both the modal frequencies and their uncertainties. We will also demonstrate the effects of some of these errors upon the inferred radial profile of the solar internal sound speed. Among the different possible systematic errors which we will discuss are the effects of: 1)the asymmetric shapes of the peaks in observational power spectra, 2)the realization noise which is present in the case of the low-degree modes, 3)the different frequency estimation methods used on different types of power spectra (i.e., on either tesseral power spectra or on m-averaged power spectra), 4) the differences in the frequencies which are estimated from velocity- and intensity-based power spectra, 5) the blending of individual p-modes into so-called "ridges" of observed power at both high degrees and high frequencies, and 6) the spatial and temporal aliasing which occurs at both high degrees and at high frequencies. We will demonstrate these different errors using results obtained with the VIRGO and MDI experiments onboard the SOHO spacecraft. We will also compare some of these space-based results with the results of similar estimates obtained from co-temporaneous ground-based observations, such as from the Mt. Wilson 60-Foot Solar Tower. We will include the results from different structural inversions carried out with different sets of input frequencies and uncertainties in order to demonstrate the effects of these different systematic errors upon the inverted internal sound speed profile. Title: An estimate of the solar background irradiance power spectrum. Authors: Rabello-Soares, M. C.; Roca Cortes, T.; Jimenez, A.; Andersen, B. N.; Appourchaux, T. Bibcode: 1997A&A...318..970R Altcode: Knowledge of the solar irradiance background is of great importance to solar and stellar physics. In particular, its contribution to the solar oscillations power spectrum is highly relevant as it represents the ultimate limit to the sensitivity of solar oscillations' observations. An analysis of the power spectra of the solar photometric data coming from four different instruments - two space-borne (ACRIM and IPHIR) and two earth-based instruments (SLOT and LOI-T) - has been performed to obtain the upper limit to the solar irradiance background's spectrum. These observations have been compared to a numerical model computed for the non-coherent solar surface phenomena, namely granulation, mesogranulation and supergranulation. There is an overall good agreement between the general trend of the model and the observed data. Title: First results from VIRGO on SoHO Authors: Frohlich, C.; Andersen, B. N.; Appourchaux, T.; Berthomieu, G.; Crommelynck, D. A.; Domingo, V.; Fichot, A.; Finsterle, W.; Gómez, M. F.; Gough, D.; Jiménez, A.; Leifsen, T.; Lombaerts, M.; Pap, J. M.; Provost, J.; Roca Cortés, T.; Romero, J.; Roth, H. -J.; Sekii, T.; Telljohann, U.; Toutain, T.; Wehrli, C. Bibcode: 1997IAUS..181...67F Altcode: No abstract at ADS Title: In-Flight Performance of the Virgo Luminosity Oscillations Imager Aboard SOHO Authors: Appourchaux, Thierry; Andersen, Bo N.; Fröhlich, Claus; Jiménez, Antonio; Telljohann, Udo; Wehrli, Christoph Bibcode: 1997SoPh..170...27A Altcode: The Luminosity Oscillations Imager (LOI) is a part of the VIRGO instrument aboard the Solar and Heliospheric Observatory (SOHO). The scientific objective of the LOI experiment is to identify and characterize pressure and internal gravity oscillations of the Sun by observing the radiance variations. The LOI is a low-resolution imager with 12 pixels, for the measurement of the radiance distribution over the solar disk at 500 nm. The low resolution capability of the instrument allows the identification of individual azimuthal orders for l = 0 to 7, without suffering the mixing that affects integrated solar disk instruments. The performance, calibrations and instrumental effects of the LOI are described together with the procedures for extracting the solar p modes. Title: First Results from VIRGO, the Experiment for Helioseismology and Solar Irradiance Monitoring on SOHO Authors: Fröhlich, Claus; Andersen, Bo N.; Appourchaux, Thierry; Berthomieu, Gabrielle; Crommelynck, Dominique A.; Domingo, Vicente; Fichot, Alain; Finsterle, Wolfgang; Gómez, Maria F.; Gough, Douglas; Jiménez, Antonio; Leifsen, Torben; Lombaerts, Marc; Pap, Judit M.; Provost, Janine; Roca Cortés, Teodoro; Romero, José; Roth, Hansjörg; Sekii, Takashi; Telljohann, Udo; Toutain, Thierry; Wehrli, Christoph Bibcode: 1997SoPh..170....1F Altcode: First results from the VIRGO experiment (Variability of solar IRradiance and Gravity Oscillations) on the ESA/NASA Mission SOHO (Solar and Heliospheric Observatory) are reported. The observations started mid-January 1996 for the radiometers and sunphotometers and near the end of March for the luminosity oscillation imager. The performance of all the instruments is very good, and the time series of the first 4-6 months are evaluated in terms of solar irradiance variability, solar background noise characteristics and p-mode oscillations. The solar irradiance is modulated by the passage of active regions across the disk, but not all of the modulation is straightforwardly explained in terms of sunspot flux blocking and facular enhancement. Helioseismic inversions of the observed p-mode frequencies are more-or-less in agreement with the latest standard solar models. The comparison of VIRGO results with earlier ones shows evidence that magnetic activity plays a significant role in the dynamics of the oscillations beyond its modulation of the resonant frequencies. Moreover, by comparing the amplitudes of different components ofp -mode multiplets, each of which are influenced differently by spatial inhomogeneity, we have found that activity enhances excitation. Title: VIRGO: Experiment for Helioseismology and Solar Irradiance Monitoring Authors: Fröhlich, Claus; Romero, José; Roth, Hansjörg; Wehrli, Christoph; Andersen, Bo N.; Appourchaux, Thierry; Domingo, Vicente; Telljohann, Udo; Berthomieu, Gabrielle; Delache, Philippe; Provost, Janine; Toutain, Thierry; Crommelynck, Dominique A.; Chevalier, André; Fichot, Alain; Däppen, Werner; Gough, Douglas; Hoeksema, Todd; Jiménez, Antonio; Gómez, Maria F.; Herreros, José M.; Cortés, Teodoro Roca; Jones, Andrew R.; Pap, Judit M.; Willson, Richard C. Bibcode: 1995SoPh..162..101F Altcode: The scientific objective of the VIRGO experiment (Variability of solar IRradiance and Gravity Oscillations) is to determine the characteristics of pressure and internal gravity oscillations by observing irradiance and radiance variations, to measure the solar total and spectral irradiance and to quantify their variability over periods of days to the duration of the mission. With these data helioseismological methods can be used to probe the solar interior. Certain characteristics of convection and its interaction with magnetic fields, related to, for example, activity, will be studied from the results of the irradiance monitoring and from the comparison of amplitudes and phases of the oscillations as manifest in brightness from VIRGO, in velocity from GOLF, and in both velocity and continuum intensity from SOI/MDI. The VIRGO experiment contains two different active-cavity radiometers for monitoring the solar `constant', two three-channel sunphotometers (SPM) for the measurement of the spectral irradiance at 402, 500 and 862 nm, and a low-resolution imager (LOI) with 12 pixels, for the measurement of the radiance distribution over the solar disk at 500 um. In this paper the scientific objectives of VIRGO are presented, the instruments and the data acquisition and control system are described in detail, and their measured performance is given. Title: An Attempt to Estimate the Intensity Background Spectra Authors: Rabello Soares, M. C.; Roca Cortés, T.; Jiménez, A.; Appourchaux, T. Bibcode: 1995ESASP.376b.397R Altcode: 1995help.confP.397R; 1995soho....2..397R No abstract at ADS Title: The Luminosity Oscillations Imager on Board Virgo: Design and Performances Authors: Appourchaux, T.; Telljohann, U.; Martin, D.; Fleur, J.; Lévêque, S. Bibcode: 1995ESASP.376b.359A Altcode: 1995soho....2..359A; 1995help.confP.359A No abstract at ADS Title: Results from the Luminosity Oscillations Imager Authors: Appourchaux, T.; Toutain, T.; Jiménez, A.; Rabello Soares, M. C.; Andersen, B. N.; Jones, A. R. Bibcode: 1995ESASP.376b.265A Altcode: 1995help.confP.265A; 1995soho....2..265A No abstract at ADS Title: Preliminary Analysis of the Radius Signal on Loi-T Authors: Rabello-Soares, M. C.; Appourchaux, T.; Jiménez, A.; Roca Cortés, T. Bibcode: 1995ESASP.376b.365R Altcode: 1995help.confP.365R; 1995soho....2..365R No abstract at ADS Title: Solar P-Mode Frequencies from the IRIS Network Authors: Gelly, B.; Fossat, E.; Palle, P.; Appourchaux, T.; Eghamberdiev, S.; Fierry-Fraillon, D.; Grec, G.; Hoeksema, J. T.; Khalikov, S.; Lazrek, M.; Loudagh, S.; Pantel, A.; Regulo, C.; Sanchez, L.; Schmider, F. X. Bibcode: 1995ESASP.376b.373G Altcode: 1995help.confP.373G; 1995soho....2..373G No abstract at ADS Title: Frequencies and splittings of low-degree solar P modes: results of the Luminosity Oscillations Imager. Authors: Appourchaux, T.; Toutain, T.; Telljohann, U.; Jimenez, A.; Rabello-Soares, M. C.; Andersen, B. N.; Jones, A. R. Bibcode: 1995A&A...294L..13A Altcode: The Luminosity Oscillations Imager is a part of the VIRGO instrument to be flown aboard the Solar and Heliospheric Observatory in mid 1995. Using a ground-based version of the instrument, we have detected low-l modes with a time series spanning 163 days. The low resolution capability of the instrument allows the identification of individual tesseral orders for l=2 to 5. The data reduction method prevents from observing the l=0 modes, and reduces the amplitude of the l=1 modes with m=+/-1. The frequencies and, for the first time, the linear component of the mode splitting (a_1_) are given for l=2 to 5 for each order n. The frequencies and the a_1_ are obtained by fitting simultaneously the 2l+1 spectra using maximum likelihood estimators. The splittings are compared with other published values. Title: STARS: A Proposal for a Dedicated Space Mission to Study Stellar Structure and Evolution Authors: Fridlund, M.; Gough, D. O.; Jones, A.; Appourchaux, T.; Badiali, M.; Catala, C.; Frandsen, S.; Grec, G.; Roca Cortes, T.; Schrijver, K. Bibcode: 1995ASPC...76..416F Altcode: 1995gong.conf..416F No abstract at ADS Title: Testing the Statistical Significance of the Asymmetries of p-Mode Line Profiles: Application to the IPHIR Data Authors: Appourchaux, T.; Toutain, T.; Gough, D. O.; Kosovichev, A. Bibcode: 1995ASPC...76..314A Altcode: 1995gong.conf..314A No abstract at ADS Title: VIRGO - the Solar Monitor Experiment on SOHO Authors: Appourchaux, T.; Domingo, V.; Frohlich, C.; Romero, J.; Wehrli, C.; Andersen, B. N.; Berthomieu, G.; Delache, P.; Crommelynck, D.; Jimenez, A.; Roca Cortes, T.; Jones, A. R. Bibcode: 1995ASPC...76..408A Altcode: 1995gong.conf..408A No abstract at ADS Title: Frequencies and splittings of low-degree solar p modes: Results of the Luminosity Oscillations Imager Authors: Appourchaux, T. Bibcode: 1995HiA....10..336A Altcode: No abstract at ADS Title: Maximum likelihood estimators: an application to the estimation of the precision of helioseismic measurements. Authors: Toutain, T.; Appourchaux, T. Bibcode: 1994A&A...289..649T Altcode: In this paper we apply the theory of Maximum Likelihood estimators to determine the precision of parameters in fitting Lorentzian profiles to helioseismic power spectra. The precision of frequency, linewidth, amplitude and noise determination for a single p mode, and of the l=1 splitting, are derived as a function of the signal-to-noise ratio and the spectral resolution of the spectrum. Libbrecht's formula (Libbrecht 1992) for frequency precision is derived in a more general case. For validating the approach, the theoretical precisions are compared with those obtained with Monte-Carlo simulations and with IPHIR observations. The robustness of the precisions obtained is ideal for predictive purposes. The method used to derive the precisions is general enough so that it can be used for others purposes. Title: STARS - an investigation of stellar structure and evolution. Authors: Fridlund, M.; Appourchaux, T.; Pace, O.; Volunte, S. Bibcode: 1994ESAJ...18..247F Altcode: STARS is a mission targeted at the understanding of stellar physics, by carrying the established technique of helioseismology into the new field of asteroseismology. This requires the measurement of the miniscule variations in the light output of a stellar object that result when acoustical waves hit the outer boundary of its surface. These waves penetrate to the very center of the object and thus carry information about the interior. In order to detect these variations, STARS will have to carry the measuring of stellar flux to new limits. Intimately coupled to the properties of the stellar interior is the surface activity. A second part of the STARS experiment focuses on time-resolved observations of this activity, providing information about the outer boundary of the star, stellar rotation and angular momentum transport, as well as magnetic and chromospheric acitivity. Title: PRISMA - Probing Rotation and Interior of Stars: Microvariability and Activity. Report on the phase A study. Authors: Appourchaux, T. Bibcode: 1993pris.book.....A Altcode: The PRISMA mission addresses one of the most fundamental areas of astronomy: the structure and evolution of the stars. It uses the new technique of asteroseismology, measuring the surface amplitude of oscillations which penetrate deep into the interior of stars, whilst simultaneously monitoring surface activity. Title: Prisma - the First Space Mission to See Inside the Stars Authors: Appourchaux, T.; Gough, D. O.; Catala, C.; Frandsen, S.; Frohlich, C.; Hoyng, P.; Jones, A.; Lemaire, P.; Tondello, G.; Weiss, W. W. Bibcode: 1993ASPC...42..411A Altcode: 1993gong.conf..411A No abstract at ADS Title: Stellar seismology and activity: the need to go to space (PRISMA) (invited paper) Authors: Appourchaux, T.; Catala, C.; Catalano, S.; Frandsen, S.; Jones, A.; Lemaire, P.; Weiss, W. W. Bibcode: 1993MmSAI..64..415A Altcode: No abstract at ADS Title: PRISMA. Probing Rotation and Interior of Stars: Microvariability and activity Authors: Appourchaux, T.; Catala, C.; Cornelisse, J. Bibcode: 1993ppri.book.....A Altcode: No abstract at ADS Title: PRISMA - the first space mission to see inside the stars. Authors: Appourchaux, T.; Fridlund, M.; Cornelisse, J.; Volonté, S. Bibcode: 1993ESAJ...17..239A Altcode: The PRISMA - Probing Rotation and Interior of Stars: Microvariability and Activity - mission addresses one of the most fundamental areas of astronomy: the structure and evolution of stars. It uses the new technique of asteroseismology, measuring the surface manifestation of oscillations that penetrate deep into the interiors of stars, whilst simultaneously monitoring surface activity. Title: PRISMA: Probing Stars from Core to Corona Authors: Appourchaux, T.; Catala, C.; Catalano, S.; Fransden, S.; Fröhlich, C.; Gough, D. O.; Hoyng, P.; Jones, A.; Lemaire, P.; Tondello, G.; Weiss, W. Bibcode: 1993ASSL..183..505A Altcode: 1993pssc.symp..505A No abstract at ADS Title: PRISMA: a new space mission for stellar physics. Authors: Appourchaux, T.; Gough, D.; Hyoyng, P.; Catala, C.; Frandsen, S.; Froehlich, C.; Jones, A.; Lemaire, P.; Tondello, G.; Weiss, W. W. Bibcode: 1993ASPC...40..812A Altcode: 1993ist..proc..812A; 1993IAUCo.137..812A This paper mainly focuses on the scientific objectives that can be achieved with a new space mission of the European Space Agency - PRISMA (Probing Rotation and Interior of Stars: Microvariability and Activity). The scientific objectives can be classified into three areas of interest: (1) Stellar structure and evolution. (2) Stellar atmospheres and magnetic fields. (3) Stellar dynamics and stellar dynamos. Title: Passive thermal control of a multilayer filter for space-based solar observations. Authors: Appourchaux, Thierry; Cislaghi, Massimo Bibcode: 1992OptEn..31.1715A Altcode: Temperature distributions inside multilayer filters are often required to assess performance. This subject is rarely treated in the literature. Guidelines were developed that can be used to calculate a thermal model for various applications. In this study the guidelines are applied to an optical filter. This filter, which is not actively thermally controlled, is the front element in a space experiment devoted to the observation of solar intensity fluctuations. Temperature distributions were calculated for different designs. The final design minimizes temperature gradients, as well as degradation effects due to UV and particle radiation. The effect of space exposure on temperature distributions inside the filter is also addressed. Title: ESA's report to the 29th COSPAR Meeting Authors: Appourchaux, T.; Chicarro, A.; Domingo, V.; Fridlund, M.; Huber, M.; Innocenti, L.; Jakobsen, P.; Kessler, M.; Lebreton, J. P.; Parmar, A. Bibcode: 1992wadc.meet.....A Altcode: All ESA missions in operation, under development, or in planning are described. Missions beyond the operational phase are also presented if considerable effort is still being expended in supporting the data analysis through an archive. The aging and completed missions are: IUE, Exosat, Hipparcos, Giotto extended mission, Ulysses, and Hubble Space Telescope. The projects under development are: Infrared Space Observatory (ISO), the Solar Terrestrial Science Program (STSP) (which comprises the four Cluster spacecraft and the Solar and Heliospheric Observatory (SOHO)), the X-ray Multimirror Mission (XMM) and the Cassini/Huygens mission. Missions under study are: the Far Infrared Space Telescope (FIRST), the comet nucleus sample return (Rosetta), the International Gamma Ray Laboratory (INTEGRAL), a network of three semi hard landers to be placed on the Martian surface (MARSNET), a mission for probing the interior and rotation of stars (PRISMA), and a Satellite Test of the Equivalence Principle (STEP). Missions beyond Horizon 2000 are: Return to the Moon, interferometry from space, and Vulcan. ESA platforms described are Eureca (the European retrieval carrier) and Simuris (a solar system and stellar interferometric mission for ultrahigh resolution imaging and spectroscopy). Title: PRISMA: A Space Facility for Studying the Rotation; Interior of Stars Authors: Lemaire, P.; Appourchaux, T.; Jones, A.; Catala, C.; Catalano, S.; Frandsen, S.; Weiss, W. Bibcode: 1992ASPC...26..643L Altcode: 1992csss....7..643L No abstract at ADS Title: Prisma - a Space Facility for Studying Rotation and Activity Authors: Lemaire, P.; Appourchaux, T.; Catala, C.; Catalano, S.; Frandsen, S.; Jones, A.; Weiss, W. Bibcode: 1991ASIC..340..397L Altcode: 1991amey.conf..397L No abstract at ADS Title: PRISMA: Probing Rotation and Interior of Stars. Microvariability and activity Authors: Appourchaux, T.; Catala, C.; Catalano, S. Bibcode: 1991ppri.book.....A Altcode: No abstract at ADS Title: Prisma-probing rotation and interior of stars: Microvariability and activity Authors: Lemaire, P.; Appourchaux, T.; Catala, C.; Catalano, S.; Frandsen, S.; Jones, A.; Weiss, W. Bibcode: 1991AdSpR..11d.141L Altcode: 1991AdSpR..11..141L The measurement of frequencies, amplitudes and lifetimes of solar oscillations has proven to be a very powerful tool to sound the properties of the solar internal structure. Combined with observations of emerging solar magnetic field parameters of the solar internal structure and dynamo can be inferred. The same techniques may be used to sound stellar interiors: asteroseismology and observation of magnetic activity (emerging magnetic fields). The observation of photometric fluctuations down to micromagnitudes on stars along or near the main sequence when complemented with measurements of activity levels will provide a wealth of information on the internal structure and rotation rates, and its evolutions with age. The PRISMA mission is an ESA Assessment Study currently underway. We present here the scientific objectives of the mission, the measurements to be made, the techniques to be used, and the main characteristics of a model payload. Title: Observations of Low-Degree Solar Oscillations with Few Detector Elements Authors: Appourchaux, T.; Andersen, B. N. Bibcode: 1990SoPh..128...91A Altcode: 1990IAUCo.121P..91A The detection of low-degree solar oscillation modes with a specific low-resolution detector configuration is investigated. The detector is part of an instrument (the Luminosity Oscillations Imager) in the VIRGO package, to be flown on SOHO. Various problems such as p- and g-mode sensitivity, B and roll angle effects, modes isolation, cross-talk and guiding effects are treated for a given detector configuration. The computed sensitivity will enable the instrument to detect any type of modes for l < 6.B and roll angle effects can be compensated by using adequate filters for mode isolation. Guiding effects are small for p-modes. Also some other complex high-degree mode effects are treated. Title: ESA's report to the 28th COSPAR meeting, The Hague (Netherlands), Jun 1990. Authors: Appourchaux, T.; Burke, W. R. Bibcode: 1990ert..book.....A Altcode: This report, presented to COSPAR's biennial meeting, covers the period May 1989 to April 1990. It describes all missions in the planning stage and under development, as well as missions in operation. Missions beyond the operational phase are also presented, if considerable effort is still being expended on establishing data bases or on data analysis. Contents: 1. Introduction. 2. On-going & completed missions: IUE, Exosat, Hipparcos, Giotto extended mission. 3. Projects under development: Ulysses, Hubble Space Telescope, ISO, STSP (The Solar-Terrestrial Science Programme), Cassini/Huygens, XMM. 4. Missions under study: Cornerstone missions (FIRST, Rosetta), assessment studies, Third Millenium missions (Mars exploration, interferometry from space, Vulcan). 5. Platforms: Eureca A, Columbus Polar Platform. 6. Bibliography. Title: Optimization of parameters for helioseismology experiments measuring solar radial velocities Authors: Appourchaux, T. Bibcode: 1989A&A...222..361A Altcode: Solar-oscillation instruments have many common characteristics, such as detecting solar radial velocities on Fraunhofer lines with a 2-point measuring technique, high spectral resolution and stability, etc. The 2-point measuring technique is described including spectral responses of filter and blocker, calibration, sensitivity and photon noise. Optimization of different parameters such as filter profile, filter bandwidth, filter scanning range, line profile, line depth and prefilter bandwidth is addressed by means of a simple model. This analysis is then applied to existing or future helioseismology instruments. Title: The stable solar analyzer. Authors: Rust, D. M.; Appourchaux, T. Bibcode: 1988ESASP.286..227R Altcode: 1988ssls.rept..227R This paper presents a progress report on the development of an instrument with very high (1:1010) wavelength stability designed to measure solar surface velocities and magnetic fields. The instrument determines Doppler and Zeeman shifts in solar spectral lines by a 6-point weighted average. It is built around an electrically tunable solid lithium-niobate Fabry-Perot etalon that is stabilized against a diode laser which itself is locked to a resonance line of cesium 133. Key features are the unique etalon, which acts as a wide-angle 0.017-nm solar filter, the camera with a specially stabilized shutter, and the instrument control and data collection system. Use of the instrument in helioseismological research is emphasized. Title: Solar oscillations instrumentation and measurement theory. Authors: Appourchaux, T. Bibcode: 1988ESASP.286..595A Altcode: 1988ssls.rept..595A Solar-oscillation instruments have many common characteristics, such as detecting solar radial velocities on Fraunhofer lines with a 2-point measuring technique, high spectral resolution and stability, etc... A review of these common effects is made which can be used for optimizing most instruments in helioseismology. The choice of the spectral line is addressed for getting a high signal to solar noise ratio. Velocity imaging of solar oscillations modes is detailed including spatial sampling and span, highest observable degree. Applications of these different analysis is then applied to existing or future helioseismology instruments. Title: Performance of a Stabilized Fabry-Perot Solar Analyzer Authors: Rust, D. M.; Appourchaux, T.; Hill, F. Bibcode: 1988IAUS..123..475R Altcode: A unique solar lineshift analyzer described by Rust, Burton and Leistner (1986) has been used to study solar oscillations. Operation of this "Stabilized Solar Analyzer" depends on the electro-optic effect in crystalline lithium niobate, the substrate of the solid Fabry-Perot etalon. For 10 days in February, 1986, at the Vacuum Tower Telescope of the Sacramento Peak Observatory, the authors obtained full-disk observations of the solar oscillations. Title: Rotation in the Solar Convection Zone Inferred from Fabry-Perot Observations of the 5-MIN Oscillations Authors: Hill, F.; Rust, D. M.; Appourchaux, T. Bibcode: 1988IAUS..123...49H Altcode: Full disk observations of the 5-min solar oscillations have been obtained with a lithium niobate Fabry-Perot filter. The equatorial solar rotation rate as a function of depth has been inferred from the sectoral modes of oscillation using the Backus-Gilbert optimal averaging inversion method. The results show a rotation rate that slowly decreases over the depths of 15 to 56 Mm below the photosphere. The results are in agreement with the previous Duvall-Harvey observations. Title: The Faraday effect in a magneto-optical filter. Authors: Appourchaux, T. Bibcode: 1987SoPh..109..393A Altcode: A magneto-optical filter was built to establish its utility for measuring solar oscillations. A theoretical model is described and the asymptotic behaviour of the Faraday effect in the filter is deduced. Experimental work confirms to first order the asymptotic model. Title: Observations of Solar Oscillations with a Fabry-Perot Etalon Authors: Rust, D. M.; Hill, F.; Appourchaux, T. Bibcode: 1987BAAS...19R.933R Altcode: No abstract at ADS Title: Correction of Atmospheric Transparency Gradient Effect on Solar Radial Velocities Authors: Appourchaux, T. Bibcode: 1984srps.conf..117A Altcode: The author has found that the major part of the atmospheric gradient is that computable from sec z and standard atmospheric tables. Thus a reasonable first approximation of the velocity correction can be obtained simply by computation. The autor has demonstrated a simple system for measuring the actual gradient from which the effective spurious velocity can be computed using standard figures for limb darkening and solar rotation. Title: Développement d'un Fabry-Perot destiné à l'observation des oscillations solaires pour une mission spatiale Title: Développement d'un Fabry-Perot destiné à l'observation des oscillations solaires pour une mission spatiale Title: Development of a Fabry-Perot interferometer for the observation of solar oscillations from a space mission; Authors: Appourchaux, Thierry Bibcode: 1984PhDT........97A Altcode: No abstract at ADS