Author name code: palle ADS astronomy entries on 2022-09-14 author:"Palle, Pere" ------------------------------------------------------------------------ Title: Magnetic activities on two single-lined RS Canum Venaticorum binaries IM Pegasi and σ Geminorum Authors: Cao, Dongtao; Gu, Shenghong; Grundahl, F.; Pallé, P. L. Bibcode: 2022MNRAS.514.4190C Altcode: 2022MNRAS.tmp.1527C We present the study on continuous high-resolution spectroscopic observations of two long-period single-lined RS Canum Venaticorum (RS CVn) binary stars IM Pegasi (IM Peg) and σ Geminorum (σ Gem), obtained with the Hertzsprung SONG telescope during the 2015-2016 season. Chromospheric activity indicators Hα, $\rm{Na\,\,{\small I}}$ D1, D2 doublet, $\rm{He\,\,{\small I}}$ D3, and Hβ lines have been analysed by using the spectral subtraction technique. The expected chromospheric emission features in the Hα, $\rm{Na\,\,{\small I}}$ D1, D2 doublet, and Hβ lines confirm that both of two stars are very active systems. In the spectra, the $\rm{He\,\,{\small I}}$ D3 line had been always detected in absorption feature. Although the behaviour of chromospheric activity indicators is very similar for both stars, the activity level of IM Peg is much stronger than that of σ Gem. Moreover, the equivalent width variations of the Hα, $\rm{He\,\,{\small I}}$ D3, and Hβ line subtractions correlate well and show different behaviour among different orbital cycles, which indicates the presence and evolution of activity longitudes over the surface of two stars. Furthermore, the subtracted Hα line profile is usually asymmetric. The red-shifted excess absorption features could be interpreted as a strong down-flow of cool absorbing material, while the blue-shifted emission component is probably caused by up-flow of hot materials through microflare events. Title: Parameters of the eclipsing binary α Draconis observed by TESS and SONG Authors: Hey, Daniel R.; Kochoska, Angela; Monier, Richard; Kochukhov, Oleg; Johnston, Cole; Bedding, Timothy R.; Murphy, Simon J.; Abdul-Masih, Michael; Southworth, John; Andersen, Mads Fredslund; Grundahl, Frank; Pallé, Pere L. Bibcode: 2022MNRAS.511.2648H Altcode: 2022MNRAS.tmp..117H We present an analysis of the eclipsing single-lined spectroscopic binary system α Dra based on photometry from the Transiting Exoplanet Survey Satellite (TESS) mission and newly acquired spectroscopic measurements. Recently discovered to have eclipses in the TESS data, at a magnitude of V = 3.7, α Dra is now one of the brightest detached eclipsing binary (EB) systems known. We obtain the parameters of this system by simultaneously fitting the TESS light curve in conjunction with radial velocities (RVs) acquired from the SONG spectrograph. We determine the fractional radii (R/a) for the primary and secondary components of the system to be 0.0479 $\, \pm \,$ 0.0003 and 0.0226 $\, \pm \,$ 0.0005, respectively. We constrain the temperature, mass, and luminosity (log(L/L⊙)) of the primary to be $9975\, \pm \, 125$ K, $3.7\, \pm \, 0.1$ M⊙, and $2.49\, \pm \, 0.02$, respectively, using isochrone fitting. Although the secondary is too faint to appear in the spectra, the obtained mass function and observed inclination yields a secondary minimum mass of $M_2=2.5\, \pm \, 0.1$ M⊙, which suggests that it is an A2V type star. We were unable to obtain RVs of the secondary, and are only able to see a weak highly rotationally broadened absorption line, indicating that the secondary is rapidly rotating (vsin i ~ 200 km s-1). We also perform an abundance analysis of the primary star for 21 chemical elements. We find a complex abundance pattern, with a few elements having mild underabundances while the majority have solar abundances. We make available the PYTHON code used in this paper to facilitate future modelling of EBs. https://github.com/danhey/adra Title: VizieR Online Data Catalog: Radial velocity and transit photometry of TOI-1431 (Addison+, 2021) Authors: Addison, B. C.; Knudstrup, E.; Wong, I.; Hebrard, G.; Dorval, P.; Snellen, I.; Albrecht, S.; Bello-Arufe, A.; Almenara, J. -M.; Boisse, I.; Bonfils, X.; Dalal, S.; Demangeon, O. D. S.; Hoyer, S.; Kiefer, F.; Santos, N. C.; Nowak, G.; Luque, R.; Stangret, M.; Palle, E.; Tronsgaard, R.; Antoci, V.; Buchhave, L. A.; Gunther, M. N.; Daylan, T.; Murgas, F.; Parviainen, H.; Esparza-Borges, E.; Crouzet, N.; Narita, N.; Fukui, A.; Kawauchi, K.; Watanabe, N.; Rabus, M.; Johnson, M. C.; Otten, G. P. P. L.; Talens, G. J.; Cabot, S. H. C.; Fischer, D. A.; Grundahl, F.; Fredslund Andersen, M.; Jessen-Hansen, J.; Palle, P.; Shporer, A.; Ciardi, D. R.; Clark, J. T.; Wittenmyer, R. A.; Wright, D. J.; Horner, J.; Collins, K. A.; Jensen, E. L. N.; Kielkopf, J. F.; Schwarz, R. P.; Srdoc, G.; Yilmaz, M.; Senavci, H. V.; Diamond, B.; Harbeck, D.; Komacek, T. D.; Smith, J. C.; Wang, S.; Eastman, J. D.; Stassun, K. G.; Latham, D. W.; Vanderspek, R.; Seager, S.; Winn, J. N.; Jenkins, J. M.; Louie, D. R.; Bouma, L. G.; Twicken, J. D.; Levine, A. M.; McLean, B. Bibcode: 2022yCat..51620292A Altcode: The star TOI-1431 was observed in Sectors 15 (on Camera 2 and CCD chip number 4) and 16 (on Camera 2 and CCD chip number 3) by Transiting Exoplanet Survey Satellite (TESS) in 2min cadence mode nearly continuously between 2019 August 15 and 2019 October 7.

One full transit of TOI-1431b was observed on 2019 December 24-25 with the CDK14 telescope at Howard Community College. The observations were taken using alternating 10s exposures in the Sloan g'an d z filters, starting at 23:02 UT on December 24 at an airmass of 1.2 and finishing at 02:56 UT on December 25 at an airmass of 2.4. Two full transits of TOI-1431b were observed with MuSCAT2, one on 2020 May 16 and a second one on 2020 May 24, using simultaneous multicolor photometry in g',r', i' and z bands. A full transit of TOI-1431b was observed with the 0.8m Prof. Dr. Berahitdin Albayrak Telescope (T80) at the AUKR on 2020 June 16 in the Sloan z band. We used the 0.3m telescope at the Kotizarovci Observatory near Viskovo, Croatia, to observe a full transit of TOI-1431b on 2020 August 8. On 2020 September 20, we observed a full transit of TOI-1431b from the 0.6m ULMT at Mt Lemmon using the Sloan z' filter. A full transit of TOI-1431b was observed on 2020 October 14 from the LCOGT 1.0m network node at McDonald Observatory near Fort Davis, Texas (LCO-McD), in PANSTARRS Y band.

High-resolution spectroscopic observations of TOI-1431 were obtained using the robotic Stellar Observations Network Group (SONG) 1m Hertzsprung telescope at the Teide Observatory in Tenerife. (R=90000 between 4400 and 6900Å). TOI-1431 was observed with the fiber-fed SOPHIE HR echelle spectrograph on the 1.93m telescope at the Haute-Provence Observatory between 2019 December 18 and 2020 January 12. (R=75000 at 5500Å). We acquired 52 spectra of TOI-1431 using the Fibre-fed Echelle Spectrograph (FIES) at the 2.56m Nordic Optical Telescope (NOT) of Roque de los Muchachos Observatory (La Palma, Spain). (R=67000 at 3760-8220Å). We triggered observations of TOI-1431 on the Network of Robotic Echelle Spectrographs (NRES) operated by the LCOGT. (R=53000 between 380 and 860nm). We observed TOI-1431 with the Extreme Precision Spectrometer (EXPRES), which was recently commissioned at the 4.3m Lowell Discovery Telescope. (R~137500 between 380 and 780nm).

(4 data files). Title: HiRISE - High-Resolution Imaging and Spectroscopy Explorer - Ultrahigh resolution, interferometric and external occulting coronagraphic science Authors: Erdélyi, Robertus; Damé, Luc; Fludra, Andrzej; Mathioudakis, Mihalis; Amari, T.; Belucz, B.; Berrilli, F.; Bogachev, S.; Bolsée, D.; Bothmer, V.; Brun, S.; Dewitte, S.; de Wit, T. Dudok; Faurobert, M.; Gizon, L.; Gyenge, N.; Korsós, M. B.; Labrosse, N.; Matthews, S.; Meftah, M.; Morgan, H.; Pallé, P.; Rochus, P.; Rozanov, E.; Schmieder, B.; Tsinganos, K.; Verwichte, E.; Zharkov, S.; Zuccarello, F.; Wimmer-Schweingruber, R. Bibcode: 2022ExA...tmp...21E Altcode: Recent solar physics missions have shown the definite role of waves and magnetic fields deep in the inner corona, at the chromosphere-corona interface, where dramatic and physically dominant changes occur. HiRISE (High Resolution Imaging and Spectroscopy Explorer), the ambitious new generation ultra-high resolution, interferometric, and coronagraphic, solar physics mission, proposed in response to the ESA Voyage 2050 Call, would address these issues and provide the best-ever and most complete solar observatory, capable of ultra-high spatial, spectral, and temporal resolution observations of the solar atmosphere, from the photosphere to the corona, and of new insights of the solar interior from the core to the photosphere. HiRISE, at the L1 Lagrangian point, would provide meter class FUV imaging and spectro-imaging, EUV and XUV imaging and spectroscopy, magnetic fields measurements, and ambitious and comprehensive coronagraphy by a remote external occulter (two satellites formation flying 375 m apart, with a coronagraph on a chaser satellite). This major and state-of-the-art payload would allow us to characterize temperatures, densities, and velocities in the solar upper chromosphere, transition zone, and inner corona with, in particular, 2D very high resolution multi-spectral imaging-spectroscopy, and, direct coronal magnetic field measurement, thus providing a unique set of tools to understand the structure and onset of coronal heating. HiRISE's objectives are natural complements to the Parker Solar Probe and Solar Orbiter-type missions. We present the science case for HiRISE which will address: i) the fine structure of the chromosphere-corona interface by 2D spectroscopy in FUV at very high resolution; ii) coronal heating roots in the inner corona by ambitious externally-occulted coronagraphy; iii) resolved and global helioseismology thanks to continuity and stability of observing at the L1 Lagrange point; and iv) solar variability and space climate with, in addition, a global comprehensive view of UV variability. Title: No swan song for Sun-as-a-star helioseismology: Performances of the Solar-SONG prototype for individual mode characterisation Authors: Breton, S. N.; Pallé, P. L.; García, R. A.; Fredslund Andersen, M.; Grundahl, F.; Christensen-Dalsgaard, J.; Kjeldsen, H.; Mathur, S. Bibcode: 2022A&A...658A..27B Altcode: 2021arXiv211012698B The GOLF instrument on board SoHO has been in operation for almost 25 years, but the ageing of the instrument has now strongly affected its performance, especially in the low-frequency pressure-mode (p-mode) region. At the end of the SoHO mission, the ground-based network BiSON will remain the only facility able to perform Sun-integrated helioseismic observations. Therefore, we want to assess the helioseismic performances of an échelle spectrograph such as SONG. The high precision of such an instrument and the quality of the data acquired for asteroseismic purposes call for an evaluation of the instrument's ability to perform global radial-velocity measurements of the solar disk. Data acquired during the Solar-SONG 2018 observation campaign at the Teide Observatory are used to study mid- and low-frequency p modes. A Solar-SONG time series of 30 days in duration is reduced with a combination of the traditional IDL iSONG pipeline and a new Python pipeline described in this paper. A mode fitting method built around a Bayesian approach is then performed on the Solar-SONG and contemporaneous GOLF, BiSON, and HMI data. For this contemporaneous time series, Solar-SONG is able to characterise p modes at a lower frequency than BiSON or GOLF (1750 μHz versus 1946 and 2157 μHz, respectively), while for HMI it is possible to characterise a mode at 1686 μHz. The decrease in GOLF sensitivity is then evaluated through the evolution of its low-frequency p-mode characterisation abilities over the years: a set of 30-day-long GOLF time series, considered at the same period of the year from 1996 to 2017, is analysed. We show that it is more difficult to accurately characterise p modes in the range 1680 to 2160 μHz when considering the most recent time series. By comparing the global power level of different frequency regions, we also observe that the Solar-SONG noise level in the 1000 to 1500 μHz region is lower than for any GOLF subseries considered in this work. While the global p-mode power-level ratio is larger for GOLF during the first years of the mission, this ratio decreases over the years and is bested by Solar-SONG for every time series after 2000. All these observations strongly suggest that efforts should be made towards deploying more Solar-SONG nodes in order to acquire longer time series with better duty cycles. Title: Analysing Kepler stellar surface rotation and activity with ROOSTER Authors: Breton, S. N.; Santos, A. R. G.; Mathur, S.; García, R. A.; Bugnet, L.; Pallé, P. L. Bibcode: 2021sf2a.conf..363B Altcode: It is crucial for our knowledge of stellar evolution to be able to efficiently determine stellar surface rotation periods in large stellar samples. Random forest (RF) learning abilities are exploited to automate the extraction of rotation periods in Kepler light curves. We train three different classifiers: one to detect if rotational modulation is present in the light curve; one to select the rotation period among estimates provided by ACF and wavelet analysis methods; and finally one to flag classical pulsators or close binary candidates that can bias our rotation-period determination. We test our machine learning pipeline, ROOSTER, on the Kepler K and M dwarf sample using the most up-to-date reference catalog. We show that we are able to detect rotational modulations with an accuracy of 94.2% and to retrieve final rotation periods with an accuracy of 95.3%. This value is raised to 99.5% after visually inspecting 25.2% of the stars. Over the two main analysis steps, the pipeline yields a global accuracy of 92.1% before visual checks, 96.9% after. The method is then applied to analyse the F and G stars observed by Kepler. The methodology presented here can be adapted to extract surface rotation periods for stars observed by other missions, like K2, TESS, and PLATO. Title: TOI-1431b/MASCARA-5b: A Highly Irradiated Ultrahot Jupiter Orbiting One of the Hottest and Brightest Known Exoplanet Host Stars Authors: Addison, Brett C.; Knudstrup, Emil; Wong, Ian; Hébrard, Guillaume; Dorval, Patrick; Snellen, Ignas; Albrecht, Simon; Bello-Arufe, Aaron; Almenara, Jose-Manuel; Boisse, Isabelle; Bonfils, Xavier; Dalal, Shweta; Demangeon, Olivier D. S.; Hoyer, Sergio; Kiefer, Flavien; Santos, N. C.; Nowak, Grzegorz; Luque, Rafael; Stangret, Monika; Palle, Enric; Tronsgaard, René; Antoci, Victoria; Buchhave, Lars A.; Günther, Maximilian N.; Daylan, Tansu; Murgas, Felipe; Parviainen, Hannu; Esparza-Borges, Emma; Crouzet, Nicolas; Narita, Norio; Fukui, Akihiko; Kawauchi, Kiyoe; Watanabe, Noriharu; Rabus, Markus; Johnson, Marshall C.; Otten, Gilles P. P. L.; Jan Talens, Geert; Cabot, Samuel H. C.; Fischer, Debra A.; Grundahl, Frank; Fredslund Andersen, Mads; Jessen-Hansen, Jens; Pallé, Pere; Shporer, Avi; Ciardi, David R.; Clark, Jake T.; Wittenmyer, Robert A.; Wright, Duncan J.; Horner, Jonathan; Collins, Karen A.; Jensen, Eric L. N.; Kielkopf, John F.; Schwarz, Richard P.; Srdoc, Gregor; Yilmaz, Mesut; Senavci, Hakan Volkan; Diamond, Brendan; Harbeck, Daniel; Komacek, Thaddeus D.; Smith, Jeffrey C.; Wang, Songhu; Eastman, Jason D.; Stassun, Keivan G.; Latham, David W.; Vanderspek, Roland; Seager, Sara; Winn, Joshua N.; Jenkins, Jon M.; Louie, Dana R.; Bouma, Luke G.; Twicken, Joseph D.; Levine, Alan M.; McLean, Brian Bibcode: 2021AJ....162..292A Altcode: 2021arXiv210412078A We present the discovery of a highly irradiated and moderately inflated ultrahot Jupiter, TOI-1431b/MASCARA-5 b (HD 201033b), first detected by NASA's Transiting Exoplanet Survey Satellite mission (TESS) and the Multi-site All-Sky Camera (MASCARA). The signal was established to be of planetary origin through radial velocity measurements obtained using SONG, SOPHIE, FIES, NRES, and EXPRES, which show a reflex motion of K = 294.1 ± 1.1 m s-1. A joint analysis of the TESS and ground-based photometry and radial velocity measurements reveals that TOI-1431b has a mass of M p = 3.12 ± 0.18 M J (990 ± 60 M ⊕), an inflated radius of R p = 1.49 ± 0.05 R J (16.7 ± 0.6 R ⊕), and an orbital period of P = 2.650237 ± 0.000003 days. Analysis of the spectral energy distribution of the host star reveals that the planet orbits a bright (V = 8.049 mag) and young ( ${0.29}_{-0.19}^{+0.32}$ Gyr) Am type star with ${T}_{\mathrm{eff}}={7690}_{-250}^{+400}$ K, resulting in a highly irradiated planet with an incident flux of $\langle F\rangle ={7.24}_{-0.64}^{+0.68}\times $ 109 erg s-1 cm-2 ( ${5300}_{-470}^{+500}\,{S}_{\oplus }$ ) and an equilibrium temperature of T eq = 2370 ± 70 K. TESS photometry also reveals a secondary eclipse with a depth of ${127}_{-5}^{+4}$ ppm as well as the full phase curve of the planet's thermal emission in the red-optical. This has allowed us to measure the dayside and nightside temperature of its atmosphere as T day = 3004 ± 64 K and T night = 2583 ± 63 K, the second hottest measured nightside temperature. The planet's low day/night temperature contrast (~420 K) suggests very efficient heat transport between the dayside and nightside hemispheres. Given the host star brightness and estimated secondary eclipse depth of ~1000 ppm in the K band, the secondary eclipse is potentially detectable at near-IR wavelengths with ground-based facilities, and the planet is ideal for intensive atmospheric characterization through transmission and emission spectroscopy from space missions such as the James Webb Space Telescope and the Atmospheric Remote-sensing Infrared Exoplanet Large-survey. Title: ROOSTER, a machine learning tool to determine stellar surface rotation periods in Kepler data Authors: Breton, S. N.; Santos, A. R. G.; Mathur, S.; García, R. A.; Pallé, P. L.; Bugnet, L. Bibcode: 2021plat.confE..27B Altcode: The Kepler and, to a lesser extent, the CoRoT missions opened the era of large-scale photometric stellar surveys with space instruments. Corotating dark spots and bright faculae on the stellar surface lead to brightness variations and therefore those long-term photometric surveys provide ideal datasets to measure stellar surface rotation periods and build stellar rotation catalogs. Such catalogs can then be used to constrain gyrochronology models or to study the interplay between rotation and magnetic activity. Taking the best possible advantage of those large-scale surveys, the main challenge that we face today is finding efficient methods to analyse the large amount of data. It has been shown that a combination of methods (auto-correlation function, time-frequency analysis) applied on light curves with different high-pass filtering provide reliable rotation estimates. However, the results yielded by those methods require a significant amount of visual inspection.

In the work presented here, random forest learning abilities are exploited to automate the extraction of rotation periods and magnetic activity index in Kepler light curves and to reduce the number of required visual inspections in the dataset. We train three different classifiers: one to detect if rotation modulations are present in the light curve, one to flag classical pulsators or close binary candidates that can bias our rotation-period determination, and finally one classifier to provide the final rotation period. We test our machine learning pipeline, ROOSTER (Breton et al. 2021), on the Kepler K and M dwarf sample using the reference catalog of Santos et al (2019). We show that we are able to detect rotation modulations with an accuracy of 94.2% and to retrieve final rotation periods with an accuracy of 95.3%. This value is raised to 99.5% after visually inspecting 25.2% of the stars. Over the two main analysis steps, the pipeline yields a global accuracy of 92.1% before visual checks, 96.9% after. The method is then applied to analyse the F and G Kepler sample (Santos et al. 2021). This allowed us to derive the largest catalog of surface rotation periods for the Kepler targets with more than 55,000 entries. The work we performed used only time series from the Kepler mission, but the methodology presented here could be adapted to extract surface rotation periods for stars observed by other missions, like K2, TESS, or PLATO. Title: Precise radial velocities of giant stars. XV. Mysterious nearly periodic radial velocity variations in the eccentric binary ε Cygni Authors: Heeren, Paul; Reffert, Sabine; Trifonov, Trifon; Wong, Ka Ho; Lee, Man Hoi; Lillo-Box, Jorge; Quirrenbach, Andreas; Arentoft, Torben; Albrecht, Simon; Grundahl, Frank; Andersen, Mads Fredslund; Antoci, Victoria; Pallé, Pere L. Bibcode: 2021A&A...647A.160H Altcode: 2021arXiv210201999H Context. Using the Hamilton Échelle Spectrograph at Lick Observatory, we have obtained precise radial velocities (RVs) of a sample of 373 G- and K-giant stars over more than 12 yr, leading to the discovery of several single and multiple planetary systems. The RVs of the long-period (~53 yr) spectroscopic binary ε Cyg (HIP 102488) are found to exhibit additional regular variations with a much shorter period (~291 days).
Aims: We intend to improve the orbital solution of the ε Cyg system and attempt to identify the cause of the nearly periodic shorter period variations, which might be due to an additional substellar companion.
Methods: We used precise RV measurements of the K-giant star ε Cyg from Lick Observatory, in combination with a large set of RVs collected more recently with the SONG telescope, as well as archival data sets. We fit Keplerian and fully dynamical N-body models to the RVs in order to explore the properties of a previously known spectroscopic stellar companion and to investigate whether there is an additional planetary companion in the system. To search for long-term stable regions in the parameter space around the orbit of this putative planet, we ran a stability analysis using an N-body code. Furthermore, we explored the possibility of co-orbital bodies to the planet with a demodulation technique. We tested the hypothesis of ε Cyg being a hierarchical stellar triple by using a modified version of the N-body code. Alternative causes for the observed RV variations, such as stellar spots and oscillations, were examined by analyzing photometric data of the system and by comparing its properties to known variable stars with long secondary periods and heartbeat stars from the literature.
Results: Our Keplerian model characterizes the orbit of the spectroscopic binary to higher precision than achieved previously, resulting in a semi-major axis of a = 15.8 AU, an eccentricity of e = 0.93, and a minimum mass of the secondary of msini = 0.265 M⊙. Additional short-period RV variations closely resemble the signal of a Jupiter-mass planet orbiting the evolved primary component with a period of 291 d, but the period and amplitude of the putative orbit change strongly over time. Furthermore, in our stability analysis of the system, no stable orbits could be found in a large region around the best fit. Both of these findings deem a planetary cause of the RV variations unlikely. Most of the investigated alternative scenarios also fail to explain the observed variability convincingly. Due to its very eccentric binary orbit, it seems possible, however, that ε Cyg could be an extreme example of a heartbeat system.

RV data (Tables A.1 and A.2) are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/647/A160

Based on observations collected at the Lick Observatory, University of California.

Based on observations collected with the Hertzsprung SONG telescope at the Spanish Observatorio del Teide, Tenerife.

Based on data collected by the BRITE Constellation satellite mission, designed, built, launched, operated, and supported by the Austrian Research Promotion Agency (FFG), the University of Vienna, the Technical University of Graz, the University of Innsbruck, the Canadian Space Agency (CSA), the University of Toronto Institute for Aerospace Studies (UTIAS), the Foundation for Polish Science & Technology (FNiTP MNiSW), and National Science Centre (NCN). Title: ROOSTER: a machine-learning analysis tool for Kepler stellar rotation periods Authors: Breton, S. N.; Santos, A. R. G.; Bugnet, L.; Mathur, S.; García, R. A.; Pallé, P. L. Bibcode: 2021A&A...647A.125B Altcode: 2021arXiv210110152B In order to understand stellar evolution, it is crucial to efficiently determine stellar surface rotation periods. Indeed, while they are of great importance in stellar models, angular momentum transport processes inside stars are still poorly understood today. Surface rotation, which is linked to the age of the star, is one of the constraints needed to improve the way those processes are modelled. Statistics of the surface rotation periods for a large sample of stars of different spectral types are thus necessary. An efficient tool to automatically determine reliable rotation periods is needed when dealing with large samples of stellar photometric datasets. The objective of this work is to develop such a tool. For this purpose, machine learning classifiers constitute relevant bases to build our new methodology. Random forest learning abilities are exploited to automate the extraction of rotation periods in Kepler light curves. Rotation periods and complementary parameters are obtained via three different methods: a wavelet analysis, the autocorrelation function of the light curve, and the composite spectrum. We trained three different classifiers: one to detect if rotational modulations are present in the light curve, one to flag close binary or classical pulsators candidates that can bias our rotation period determination, and finally one classifier to provide the final rotation period. We tested our machine learning pipeline on 23 431 stars of the Kepler K and M dwarf reference rotation catalogue for which 60% of the stars have been visually inspected. For the sample of 21 707 stars where all the input parameters are provided to the algorithm, 94.2% of them are correctly classified (as rotating or not). Among the stars that have a rotation period in the reference catalogue, the machine learning provides a period that agrees within 10% of the reference value for 95.3% of the stars. Moreover, the yield of correct rotation periods is raised to 99.5% after visually inspecting 25.2% of the stars. Over the two main analysis steps, rotation classification and period selection, the pipeline yields a global agreement with the reference values of 92.1% and 96.9% before and after visual inspection. Random forest classifiers are efficient tools to determine reliable rotation periods in large samples of stars. The methodology presented here could be easily adapted to extract surface rotation periods for stars with different spectral types or observed by other instruments such as K2, TESS or by PLATO in the near future. Title: Observing the changing surface structures of the active K giant σ Geminorum with SONG Authors: Korhonen, H.; Roettenbacher, R. M.; Gu, S.; Grundahl, F.; Andersen, M. F.; Henry, G. W.; Jessen-Hansen, J.; Antoci, V.; Pallé, P. L. Bibcode: 2021A&A...646A...6K Altcode: 2020arXiv201215177K
Aims: We aim to study the spot evolution and differential rotation in the magnetically active cool K-type giant star σ Gem from broadband photometry and continuous spectroscopic observations that span 150 nights.
Methods: We use high-resolution, high signal-to-noise ratio spectra obtained with the Hertzsprung SONG telescope to reconstruct surface (photospheric) temperature maps with Doppler imaging techniques. The 303 observations span 150 nights and allow for a detailed analysis of the spot evolution and surface differential rotation. The Doppler imaging results are compared to simultaneous broadband photometry from the Tennessee State University T3 0.4 m Automated Photometric Telescope. The activity from the stellar chromosphere, which is higher in the stellar atmosphere, is also studied using SONG observations of Balmer Hα line profiles and correlated with the photospheric activity.
Results: The temperature maps obtained during eight consecutive stellar rotations show mainly high-latitude or polar spots, with the main spot concentrations above latitude 45°. The spots concentrate around phase 0.25 near the beginning of our observations and around phase 0.75 towards the end. The photometric observations confirm a small jump in spot phases that occurred in February 2016. The cross-correlation of the temperature maps reveals rather strong solar-like differential rotation, giving a relative surface differential rotation coefficient of α = 0.10 ± 0.02. There is a weak correlation between the locations of starspots and enhanced emission in the chromosphere at some epochs.

Tables 1 and 2, photometry, and spectra are only 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/cat/J/A+A/646/A6

Based on observations made with the Hertzsprung SONG telescope on the Spanish Observatorio del Teide on the island of Tenerife and the Tennessee State University T3 0.4-m Automated Photometric Telescope at Fairborn Observatory in Arizona. Title: Classical Astronomy as an educational resource in a Faculty of Education Authors: Eff-Darwich, Antonio; Stengler, Erik; El-Qady, Gad; Rahona, Usama; Shaker, Ashraf; Ibrahim, Makram; Núñez, Manuel; Medina, Victor; Yanes, Adán; Pallé, Pere Ll.; Martínez-Frías, Jesús Bibcode: 2021IAUS..367..411E Altcode: History, Maths and Astronomy are all mixed up in an innovative educational project that is being carried out in the Faculty of Education of the Universidad de La Laguna, in Spain. Students learn how to teach (to primary school students) about the shape of the Earth, the distances to the Moon, the Sun and other planets, collecting their own data with simple instrumentation and, most important, to connect ideas and different disciplines. The structure and contents of this project are presented, as well as examples of the activities that are carried out. Title: VizieR Online Data Catalog: sigma Gem BV photometry (Korhonen+, 2021) Authors: Korhonen, H.; Roettenbacher, R. M.; Gu, S.; Grundahl, F.; Andersen, M. F.; Henry, G. W.; Jessen-Hansen, J.; Antoci, V.; Palle, P. L. Bibcode: 2021yCat..36460006K Altcode: Photometric and spectroscopic observing logs of sigma Geminorum.

The photometric observations were obtained between 27 October 2015 and 5 May 2016 with the Tennessee State University T3 0.4m Automated Photometric Telescope at Fairborn Observatory in Arizona. The observations consist of Johnson B and V differential magnitudes, which are defined as the variable star (sigma Gem ) minus the comparison star (HD 60318). The typical standard deviation of the observations is 0.00935mag in B and 0.00840mag in V.

The spectroscopic observations were obtained with the Hertzsprung SONG telescope between 4 November 2015 and 1 April 2016. We used the spectrograph with slit #5, giving a resolving power of 77000 and covering wavelengths from 4400Å to 6900Å in 51 orders, with some small gaps redwards of 5300Å. Each individual spectrum of sigma Gem had an exposure time of 180 seconds. All the spectra are freely available in the SONG Data Archive, SODA: https://soda.phys.au.dk/

(2 data files). Title: VizieR Online Data Catalog: Radial velocity data of epsilon Cyg (Heeren+, 2021) Authors: Heeren, P.; Reffert, S.; Trifonov, T.; Wong, K. H.; Lee, M. H.; Lillo-Box, J.; Quirrenbach, A.; Arentoft, T.; Albrecht, S.; Grundahl, F.; Andersen, M. F.; Antoci, V.; Palle, P. L. Bibcode: 2021yCat..36470160H Altcode: Precise radial velocities of the giant star epsilon Cyg are presented. A total of 109 measurements of this star were taken with the Hamilton spectrograph at the Lick Observatory, from June 2000 until November 2011. Additionally, we present 228 radial velocities acquired with the Hertzsprung SONG telescope on Tenerife, from April 2015 until December 2018. Part of these data are nightly averages from higher cadence asteroseismic measurements. All observations were acquired and reduced using the iodine cell approach.

(2 data files). Title: Properties of the Hyades, the eclipsing binary HD 27130, and the oscillating red giant ɛ Tauri Authors: Brogaard, K.; Pakštienė, E.; Grundahl, F.; Mikolaitis, Š.; Tautvaišienė, G.; Slumstrup, D.; Talens, G. J. J.; VandenBerg, D. A.; Miglio, A.; Arentoft, T.; Kjeldsen, H.; Janulis, R.; Drazdauskas, A.; Marchini, A.; Minkevičiūtė, R.; Stonkutė, E.; Bagdonas, V.; Fredslund Andersen, M.; Jessen-Hansen, J.; Pallé, P. L.; Dorval, P.; Snellen, I. A. G.; Otten, G. P. P. L.; White, T. R. Bibcode: 2021A&A...645A..25B Altcode: 2020arXiv201102274B Context. The derivation of accurate and precise masses and radii is possible for eclipsing binary stars, allowing for insights into their evolution. When residing in star clusters, they provide measurements of even greater precision, along with additional information on their properties. Asteroseismic investigations of solar-like oscillations offers similar possibilities for single stars.
Aims: We wish to improve the previously established properties of the Hyades eclipsing binary HD 27130 and re-assess the asteroseismic properties of the giant star ɛ Tau. The physical properties of these members of the Hyades can be used to constrain the helium content and age of the cluster.
Methods: New multi-colour light curves were combined with multi-epoch radial velocities to yield masses and radii of HD 27130. Measurements of Teff were derived from spectroscopy and photometry, and verified using the Gaia parallax. We estimated the cluster age from re-evaluated asteroseismic properties of ɛ Tau while using HD 27130 to constrain the helium content.
Results: The masses, radii, and Teff of HD 27130 were found to be M = 1.0245 ± 0.0024 M⊙, R = 0.9226 ± 0.015 R⊙, Teff = 5650 ± 50 K for the primary, and M = 0.7426 ± 0.0016 M⊙, R = 0.7388 ± 0.026 R⊙, Teff = 4300 ± 100 K for the secondary component. Our re-evaluation of ɛ Tau suggests that the previous literature estimates are trustworthy and that the HIPPARCOS parallax is more reliable than the Gaia DR2 parallax.
Conclusions: The helium content of HD 27130 and, thus, of the Hyades is found to be Y = 0.27 but with a significant model dependency. Correlations with the adopted metallicity result in a robust helium enrichment law, with ΔY/ΔZ close to 1.2 We estimate the age of the Hyades to be 0.9 ± 0.1 (stat) ±0.1 (sys) Gyr, which is in slight tension with recent age estimates based on the cluster white dwarfs. The precision of the age estimate can be much improved via asteroseismic investigations of the other Hyades giants and by future improvements to the Gaia parallax for bright stars.

Tables 8-16 are only 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/cat/J/A+A/645/A25 Title: VizieR Online Data Catalog: HD27130 photometric light curves (Brogaard+, 2021) Authors: Brogaard, K.; Pakstiene, E.; Grundahl, F.; Mikolaitis, S.; Tautvaisiene, G.; Slumstrup, D.; Talens, G. J. J.; Vandenberg, D. A.; Miglio, A.; Arentoft, T.; Kjeldsen, H.; Janulis, R.; Drazdauskas, A.; Marchini, A.; Minkeviciute, R.; Stonkute, E.; Bagdonas, V.; Fredslund Andersen, M.; Jessen-Hansen, J.; Palle, P. L.; Dorval, P.; Snellen, I. A. G.; Otten, G. P. P. L.; White, T. R. Bibcode: 2020yCat..36450025B Altcode: We obtained photometric light curves (LCs) for HD 27130 in Johnson B, V, and Cousins I bandpasses at the Moletai Astronomical Observatory of Vilnius University (MAO, Lithuania) and the Astronomical Observatory of the University of Siena (AO SU, Italy). We also obtained the photometric light curve of HD 27130 from the MASCARA survey. These observed light curves are found in Tables 8-13.

For Modelling purposes, we combined and manipulated the light curves to remove out-of-eclipse variations, and to only include observations in or very close to eclipse. These corrected light curves are normalised to 0 mag and available in Tables 14-16.

(9 data files). Title: Asteroseismic masses of four evolved planet-hosting stars using SONG and TESS: resolving the retired A-star mass controversy Authors: Malla, Sai Prathyusha; Stello, Dennis; Huber, Daniel; Montet, Benjamin T.; Bedding, Timothy R.; Fredslund Andersen, Mads; Grundahl, Frank; Jessen-Hansen, Jens; Hey, Daniel R.; Palle, Pere L.; Deng, Licai; Zhang, Chunguang; Chen, Xiaodian; Lloyd, James; Antoci, Victoria Bibcode: 2020MNRAS.496.5423M Altcode: 2020arXiv200607649P; 2020MNRAS.tmp.1930M The study of planet occurrence as a function of stellar mass is important for a better understanding of planet formation. Estimating stellar mass, especially in the red giant regime, is difficult. In particular, stellar masses of a sample of evolved planet-hosting stars based on spectroscopy and grid-based modelling have been put to question over the past decade with claims they were overestimated. Although efforts have been made in the past to reconcile this dispute using asteroseismology, results were inconclusive. In an attempt to resolve this controversy, we study four more evolved planet-hosting stars in this paper using asteroseismology, and we revisit previous results to make an informed study of the whole ensemble in a self-consistent way. For the four new stars, we measure their masses by locating their characteristic oscillation frequency, νmax, from their radial velocity time series observed by SONG. For two stars, we are also able to measure the large frequency separation, Δν, helped by extended SONG single-site and dual-site observations and new Transiting Exoplanet Survey Satellite observations. We establish the robustness of the νmax-only-based results by determining the stellar mass from Δν, and from both Δν and νmax. We then compare the seismic masses of the full ensemble of 16 stars with the spectroscopic masses from three different literature sources. We find an offset between the seismic and spectroscopic mass scales that is mass dependent, suggesting that the previously claimed overestimation of spectroscopic masses only affects stars more massive than about 1.6 M⊙. Title: VizieR Online Data Catalog: 4 planet-hosting stars asteroseismic masses (Malla+, 2020) Authors: Malla, S. P.; Stello, D.; Huber, D.; Montet, B. T.; Bedding, T. R.; Andersen, M. F.; Grundahl, F.; Jessen-Hansen, J.; Hey, D. R.; Palle, P. L.; Deng, L.; Zhang, C.; Chen, X.; Lloyd, J.; Antoci, V. Bibcode: 2020yCat..74965423M Altcode: We tabulate the observing parameters for the four targets in our sample, observed using the Stellar Observations Network Group (SONG) telescope nodes at Tenerife and Delingha. We also tabulate the observed and derived parameters for each of our targets. The updated results from Stello et al. (2017MNRAS.472.4110S) are also provided here. We also provide the approximate frequencies of individual modes extracted from the echelle diagrams of gamma Cep and 24 Sex. Lastly, we provide the stellar masses for the evolved planet-hosting stars used for the ensemble study in this work across various literature sources

(5 data files). Title: Doppler Imaging and Differential Rotation of σ2 Coronae Borealis Using SONG Authors: Xiang, Yue; Gu, Shenghong; Cameron, A. Collier; Barnes, J. R.; Christensen-Dalsgaard, J.; Grundahl, F.; Antoci, V.; Andersen, M. F.; Pallé, P. L. Bibcode: 2020ApJ...893..164X Altcode: 2020arXiv200502592X We present new Doppler images of both components of the double-lined binary σ2 CrB, based on the high-resolution spectroscopic data collected during 11 nights in 2015 March-April. The observed spectra form two independent data sets with sufficient phase coverage. We apply the least-squares deconvolution to all observed spectra to obtain high signal-to-noise mean profiles, from which we derive the Doppler images of both components of σ2 CrB simultaneously. The surfaces of both F9 and G0 components are dominated by pronounced polar spots. The F9 component exhibits a weak spot at latitude 30° and its mid-to-low latitudes are relatively featureless. The G0 star shows an extended spot structure at latitude 30°, and its surface spot coverage is larger than that of the F9 star, which suggests a higher level of magnetic activity. With the cross-correlation method, we derive a solar-like surface differential rotation on the G0 star of σ2 CrB for the first time, and the surface shear rate is ΔΩ = 0.180 ± 0.004 rad days-1 and α = ΔΩ/Ωeq = 0.032 ± 0.001. We do not obtain a clear surface shear law for the F9 star due to the lack of mid-to-low latitude features, but detect a systematic longitude shift of high-latitude spots, which indicates a slower rotation with respect to the corotating frame. Title: Measurement of Atmospheric Scintillation during a Period of Saharan Dust (Calima) at Observatorio del Teide, Iz∼ana, Tenerife, and the Impact on Photometric Exposure Times Authors: Hale, S. J.; Chaplin, W. J.; Davies, G. R.; Elsworth, Y. P.; Howe, R.; Pallé, P. L. Bibcode: 2020PASP..132c4501H Altcode: We present scintillation noise profiles captured at the Observatorio del Teide, Izaña, Tenerife, over a one-week period in 2017 September. Contemporaneous data from the Birmingham Solar Oscillations Network (BiSON) and the Stellar Activity (STELLA) robotic telescopes provides estimates of daily atmospheric extinction allowing the scintillation noise to be placed within the context of overall atmospheric conditions. We discuss the results both in terms of the impact on BiSON spectrophotometer design, and for astronomical observations more generally. We find that scintillation noise power reduces by half at about 5 Hz, and is reduced to one tenth between 20 and 30 Hz even during periods of mild Calima, where visibility is reduced due to high concentrations of mineral dust in the atmosphere. We show that the common accepted exposure time of <10 ms for limiting the effect of scintillation noise in ground based photometry may be increased, and that depending on the application there may be little benefit to achieving exposure times shorter than 50 ms, relaxing constraints on detector gain and bandwidth. Title: A Comparison of Global Helioseismic-Instrument Performances: Solar-SONG, GOLF and VIRGO Authors: Breton, S. N.; García, R. A.; Pallé, P. L.; Mathur, S.; Hill, F.; Jain, K.; Jiménez, A.; Tripathy, S. C.; Grundahl, F.; Fredslund-Andersen, M.; Santos, A. R. G. Bibcode: 2020ASSP...57..327B Altcode: The SONG spectrograph has recently demonstrated its ability to perform solar radial velocity measurement during the first test run of the Solar-SONG initiative. A preliminary assessment of its performance is carried out here by comparing the results of Solar-SONG during the summer 2018 test run, with GOLF and VIRGO/SPM taken as reference instruments. Title: The BRITE-SONG of Aldebaran - stellar music in three voices Authors: Beck, P. G.; Kuschnig, R.; Houdek, G.; Kallinger, T.; Weiss, W. W.; Palle, P. L.; Grundahl, F.; Hatzes, A.; Parviainen, H.; Allende Prieto, C.; Deeg, H. J.; Jiménez, A.; Mathur, S.; Garcia, R. A.; White, T. R.; Bedding, T. R.; Grossmann, D. H.; Janisch, S.; Zaqarashvili, T.; Hanslmeier, A.; Zwintz, K. Bibcode: 2020svos.conf...75B Altcode: 2020arXiv200104912B Solar-like oscillations in red-giant stars are now commonly detected in thousands of stars with space telescopes such as Kepler. Parallel radial-velocity and photometric measurements would help us understand better the physics governing the amplitudes of solar-like oscillators, but most stars targetted for space photometry are too faint for light-demanding ground-based spectroscopy. The BRITE-Constellation provides a unique opportunity of monitoring in two colours the flux variations of bright luminous red giants. Those stars are also bright enough to be monitored with high-resolution spectrographs on small telescopes, such as the SONG Network. This contribution provided a first overview of our comprehensive, multi-year campaign to use both BRITE and SONG to characterize Aldebaran (one of the brightest red giants in the sky) seismically. Because luminous red giants can be seen at large distances, when characterized well they will serve as valuable benchmark stars for Galactic archeology. Title: Sun-like Oscillations in the Population II giant HD 122563 Authors: Creevey, O.; Thévénin, F.; Grundahl, F.; Corsaro, E.; Andersen, M. F.; Antoci, V.; Bigot, L.; Collet, R.; Pallé, P. L.; Pichon, B.; Salabert, D. Bibcode: 2019sf2a.conf..425C Altcode: 2020arXiv200513883C We have been monitoring the metal-poor Population II giant, HD 122563, for radial velocity variations since 2016 using the SONG telescope on Tenerife. We have detected the global seismic quantity \numax\ which provides information related to the stellar parameters. By combining these data with complementary data, we derive a new precise surface gravity, radius and distance to the star. Our results are corroborated by using the parallax from Gaia DR2. We present these results and some of their implications. Title: Determining surface rotation periods of solar-like stars observed by the Kepler mission using machine learning techniques Authors: Breton, S. N.; Bugnet, L.; Santos, A. R. G.; Le Saux, A.; Mathur, S.; Pallé, P. L.; García, R. A. Bibcode: 2019sf2a.conf..421B Altcode: 2019arXiv190609609B For a solar-like star, the surface rotation evolves with time, allowing in principle to estimate the age of a star from its surface rotation period. Here we are interested in measuring surface rotation periods of solar-like stars observed by the NASA mission Kepler. Different methods have been developed to track rotation signals in Kepler photometric light curves: time-frequency analysis based on wavelet techniques, autocorrelation and composite spectrum. We use the learning abilities of random forest classifiers to take decisions during two crucial steps of the analysis. First, given some input parameters, we discriminate the considered Kepler targets between rotating MS stars, non-rotating MS stars, red giants, binaries and pulsators. We then use a second classifier only on the MS rotating targets to decide the best data-analysis treatment. Title: Measurement of atmospheric scintillation during a period of Saharan dust (Calima) at Observatorio del Teide, Izaña, Tenerife, and the impact on photometric exposure times Authors: Hale, S J; Chaplin, W J; Davies, G R; Elsworth, Y P; Howe, R; Pallé, P L Bibcode: 2019arXiv191212237H Altcode: We present scintillation noise profiles captured at the Observatorio del Teide, Izaña, Tenerife, over a one-week period in September 2017. Contemporaneous data from the Birmingham Solar Oscillations Network (BiSON) and the Stellar Activity (STELLA) robotic telescopes provides estimates of daily atmospheric extinction allowing the scintillation noise to be placed within the context of overall atmospheric conditions. We discuss the results both in terms of the impact on BiSON spectrophotometer design, and for astronomical observations more generally. We find that scintillation noise power reduces by half at about~\SI{5}{\hertz}, and is reduced to one tenth between~\SIrange{20}{30}{\hertz} even during periods of mild Calima, where visibility is reduced due to high concentrations of mineral dust in the atmosphere. We show that the common accepted exposure time of~\SI{<10}{\milli\second} for limiting the effect of scintillation noise in ground based photometry may be increased, and that depending on the application there may be little benefit to achieving exposure times shorter than~\SI{50}{\milli\second}, relaxing constraints on detector gain and bandwidth. Title: Acoustic oscillations and dynamo action in the G8 sub-giant EK Eridani Authors: Bonanno, A.; Corsaro, E.; Del Sordo, F.; Pallé, P. L.; Stello, D.; Hon, M. Bibcode: 2019A&A...628A.106B Altcode: 2019arXiv190701338B We present further evidence of acoustic oscillations in the slowly rotating overactive G8 sub-giant EK Eri. This star was observed with the 1m Hertzsprung SONG telescope at the Observatorio del Teide for two different runs of 8 and 13 nights, respectively, that were separated by about a year. We determined a significant excess of power around νmax = 253 ± 3 μHz in the first observing run and were able to determine a large separation, Δν = 16.43 ± 0.22 μHz. No significant excess of power was instead detected in a subsequent SONG observing season, as also supported by our analysis of the simultaneous TESS photometric observations. We propose a new amplitude-luminosity relation in order to account for the missing power in the power spectrum. Based on the evolutionary stage of this object, we argue that a standard α2Ω dynamo cannot be excluded as the possible origin for the observed magnetic field.

A table of the radial velocities is only 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/628/A106 Based on observations made with the Hertzsprung SONG telescope operated on the Spanish Observatorio del Teide on the island of Tenerife by the Aarhus and Copenhagen Universities and by the Instituto de Astrofísica de Canarias. Title: VizieR Online Data Catalog: Radial velocity time series of EK Eridani (Bonanno+, 2019) Authors: Bonanno, A.; Corsaro, E.; Del Sordo, F.; Palle, P. L.; Stello, D.; Hon, M. Bibcode: 2019yCat..36280106B Altcode: Radial velocity time series of EK Eridani are presented. These data were obtained using the Hertzsprung telescope, a node of the Stellar Observations Network Group (SONG) network, located at the Observatorio del Teide on Tenerife, Spain.

(2 data files). 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: Looking for the sun within the educational core standards: the Spanish case Authors: Eff-Darwich, Antonio; Pallé, Pere Ll.; Rosenberg, Alfred Bibcode: 2019EPJWC.20001005E Altcode: Although Astronomy is engaging and motivating for both precollege and college students, it is often difficult to fit it in within the formal educational core standards. In this work, we present an analysis of the Spanish educational curricula for primary school to look for opportunities to adapt the tools and the science behind the most famous discoveries about the sun. In this way, we attempt to find opportunities to explain concepts such as: energy, electricity, magnetism, dynamics, astronomy, data analysis, algebra, arithmetics, geometry, language and communication skills, music, cooperative working, computing, the use of new technologies and problem-based learning. 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: First detection of oscillations in the Halo giant HD 122563: Validation of seismic scaling relations and new parameters Authors: Creevey, O.; Grundahl, F.; Thévenin, F.; Corsaro, E.; Pallé, P. L.; Salabert, D.; Pichon, B.; Collet, R.; Bigot, L.; Antoci, V.; Andersen, M. F. Bibcode: 2019A&A...625A..33C Altcode: 2019arXiv190202657C
Aims: The nearby metal-poor giant HD 122563 is an important astrophysical laboratory in which to test stellar atmospheric and interior physics. It is also a benchmark star for which to calibrate methods to apply to large scale surveys. Recently it has been remeasured using various methodologies given the new high precision instruments at our disposal. However, inconsistencies in the observations and models have been found.
Methods: In order to better characterise this star using complementary techniques we have been measuring its radial velocities since 2016 using the Hertzsprung telescope (SONG network node) in order to detect oscillations.
Results: In this work we report the first detections of sun-like oscillations in this star, and to our knowledge, a detection in the most metal-poor giant to date. We applied the classical seismic scaling relation to derive a new surface gravity for HD 122563 of log gν = 1.39 ± 0.01. Reasonable constraints on the mass imposed by its PopII giant classification then yields a radius of 30.8 ± 1.0 ℛ⊙. By coupling this new radius with recent interferometric measurements we infer a distance to the star of 306 ± 9 pc. This result places it further away than was previously thought and is inconsistent with the HIPPARCOS parallax. Independent data from the Gaia mission corroborate the distance hypothesis (dGDR2 = 290 ± 5 pc), and thus the updated fundamental parameters.
Conclusions: We confirm the validity of the classical seismic scaling relation for surface gravity in metal-poor and evolved star regimes. The remaining discrepancy of 0.04 dex between log gGDR2 (= 1.43 ± 0.03) reduces to 0.02 dex by applying corrections to the scaling relations based on the mean molecular weight and adiabatic exponent. The new constraints on the Hertzsprung-Russell diagram (L⋆ν = 381 ± 26 ℒ⊙) significantly reduce the disagreement between the stellar parameters and evolution models, however, a discrepancy of the order of 150 K still exists. Fine-tuned stellar evolution calculations show that this discrepancy can be reconciled by changing the mixing-length parameter by an amount (-0.35) that is in agreement with predictions from recent 3D simulations and empirical results. Asteroseismic measurements are continuing, and analysis of the full frequency data complemented by a distance estimate promises to bring important constraints on our understanding of this star and of the accurate calibration of the seismic scaling relations in this regime.

SONG radial velocities are only 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/625/A33 Title: VizieR Online Data Catalog: Radial velocity time series of HD 122563 (Creevey+, 2019) Authors: Creevey, O.; Grundahl, F.; Thevenin, F.; Corsaro, E.; Palle, P. L.; Salabert, D.; Pichon, B.; Collet, R.; Bigot, L.; Antoci, V.; Andersen, M. F. Bibcode: 2019yCat..36250033C Altcode: Radial velocity time series of HD 122563 are presented. These data were obtained using the Hertzsprung telescope, a node of the Stellar Observations Network Group (SONG) network, located at the Observatorio del Teide on Tenerife, Spain.

(1 data file). Title: Conducting the SONG: The Robotic Nature and Efficiency of a Fully Automated Telescope Authors: Fredslund Andersen, M.; Handberg, R.; Weiss, E.; Frandsen, S.; Simón-Díaz, S.; Grundahl, F.; Pallé, P. Bibcode: 2019PASP..131d5003F Altcode: 2019arXiv190107560F; 2019PASP..131d5003A We present a description of “the Conductor,” an automated software package that handles all observations at the first Stellar Observations Network Group (SONG) node telescope at the Teide Observatory on the island of Tenerife. The idea was to provide a complete description on the automated procedures for target selection and execution of observations and to demonstrate how the SONG robotic telescope is being operated. The Conductor is a software package developed in Python and running on a server in Aarhus that makes use of a large set of database tables through which it communicates with the SONG nodes. Based on a number of selection criteria the Conductor is able to identify the optimum target to be observed at any given moment, taking into account local weather conditions and technical constraints. The Conductor has made it possible for the Hertzsprung SONG telescope to become a highly sophisticated and efficient robotic telescopic facility without human interaction. It can handle everything from principal investigators submitting their proposed targets with specific settings, to the data being available for download after the observations has been carried out. At present, and thanks to the availability of the Conductor, the first node of the SONG project can be considered a world leading robotic telescope with respect to needed human interactions, efficiency, and flexibility in observing strategy. Title: Oscillations in the Sun with SONG: Setting the scale for asteroseismic investigations Authors: Fredslund Andersen, M.; Pallé, P.; Jessen-Hansen, J.; Wang, K.; Grundahl, F.; Bedding, T. R.; Roca Cortes, T.; Yu, J.; Mathur, S.; Gacia, R. A.; Arentoft, T.; Régulo, C.; Tronsgaard, R.; Kjeldsen, H.; Christensen-Dalsgaard, J. Bibcode: 2019A&A...623L...9F Altcode: 2019arXiv190210717F Context. We present the first high-cadence multiwavelength radial-velocity observations of the Sun-as-a-star, carried out during 57 consecutive days using the stellar échelle spectrograph at the Hertzsprung SONG Telescope operating at the Teide Observatory.
Aims: Our aim was to produce a high-quality data set and reference values for the global helioseismic parameters νmax, ⊙ and Δν⊙ of the solar p-modes using the SONG instrument. The obtained data set or the inferred values should then be used when the scaling relations are applied to other stars showing solar-like oscillations observed with SONG or similar instruments.
Methods: We used different approaches to analyse the power spectrum of the time series to determine νmax, ⊙: simple Gaussian fitting and heavy smoothing of the power spectrum. We determined Δν⊙ using the method of autocorrelation of the power spectrum. The amplitude per radial mode was determined using the method described in Kjeldsen et al. (2008, ApJ, 682, 1370).
Results: We found the following values for the solar oscillations using the SONG spectrograph: νmax, ⊙ = 3141 ± 12 μHz, Δν⊙ = 134.98 ± 0.04 μHz, and an average amplitude of the strongest radial modes of 16.6 ± 0.4 cm s-1. These values are consistent with previous measurements with other techniques.

Based on observations made at the Hertzsprung SONG telescope operated at the Spanish Observatorio del Teide on the island of Tenerife by the Aarhus and Copenhagen Universities and by the Instituto de Astrofísica de Canarias. Title: Asteroseismology of the Hyades red giant and planet host ɛ Tauri Authors: Arentoft, T.; Grundahl, F.; White, T. R.; Slumstrup, D.; Handberg, R.; Lund, M. N.; Brogaard, K.; Andersen, M. F.; Silva Aguirre, V.; Zhang, C.; Chen, X.; Yan, Z.; Pope, B. J. S.; Huber, D.; Kjeldsen, H.; Christensen-Dalsgaard, J.; Jessen-Hansen, J.; Antoci, V.; Frandsen, S.; Bedding, T. R.; Pallé, P. L.; Garcia, R. A.; Deng, L.; Hon, M.; Stello, D.; Jørgensen, U. G. Bibcode: 2019A&A...622A.190A Altcode: 2019arXiv190106187A Context. Asteroseismic analysis of solar-like stars allows us to determine physical parameters such as stellar mass, with a higher precision compared to most other methods. Even in a well-studied cluster such as the Hyades, the masses of the red giant stars are not well known, and previous mass estimates are based on model calculations (isochrones). The four known red giants in the Hyades are assumed to be clump (core-helium-burning) stars based on their positions in colour-magnitude diagrams, however asteroseismology offers an opportunity to test this assumption.
Aims: Using asteroseismic techniques combined with other methods, we aim to derive physical parameters and the evolutionary stage for the planet hosting star ɛ Tau, which is one of the four red giants located in the Hyades.
Methods: We analysed time-series data from both ground and space to perform the asteroseismic analysis. By combining high signal-to-noise radial-velocity data from the ground-based SONG network with continuous space-based data from the revised Kepler mission K2, we derive and characterize 27 individual oscillation modes for ɛ Tau, along with global oscillation parameters such as the large frequency separation Δν and the ratio between the amplitude of the oscillations measured in radial velocity and intensity as a function of frequency. The latter has been measured previously for only two stars, the Sun and Procyon. Combining the seismic analysis with interferometric and spectroscopic measurements, we derive physical parameters for ɛ Tau, and discuss its evolutionary status.
Results: Along with other physical parameters, we derive an asteroseismic mass for ɛ Tau of M = 2.458 ± 0.073 M⊙, which is slightly lower than previous estimates, and which leads to a revised minimum mass of the planetary companion. Noting that the SONG and K2 data are non-simultaneous, we estimate the amplitude ratio between intensity and radial velocity to be 42.2 ± 2.3 ppm m-1 s, which is higher than expected from scaling relations.

Time-series data are only 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/622/A190Based on observations made with the SONG telescopes operated on the Spanish Observatorio del Teide (Tenerife) and at the Chinese Delingha Observatory (Qinghai) by the Aarhus and Copenhagen Universities, by the Instituto de Astrofísica de Canarias and by the National Astronomical Observatories of China, and with NASA's K2 mission. Title: VizieR Online Data Catalog: eps Tau intensity and RV time-series data (Arentoft+, 2019) Authors: Arentoft, T.; Grundahl, F.; White, T. R.; Slumstrup, D.; Handberg, R.; Lund, M. N.; Brogaard, K.; Andersen, M. F.; Silva Aguirre, V.; Zhang, C.; Chen, X.; Yan, Z.; Pope, B. J. S.; Huber, D.; Kjeldsen, H.; Christensen-Dalsgaard, J.; Jessen-Hansen, J.; Antoci, V.; Frandsen, S.; Bedding, T. R.; Palle, P. L.; Garcia, R. A.; Deng, L.; Hon, M.; Stello, D.; Jorgensen, U. G. Bibcode: 2019yCat..36220190A Altcode: Time-series data for epsilon Tau; photometric time-series data from the revised Kepler mission K2 and radial-velocity measurements from SONG (Stellar Observations Network Group). The time series have been filtered in order to remove variations and instrumental effects at low frequencies.

(2 data files). Title: The mass and age of the first SONG target: the red giant 46 LMi Authors: Frandsen, S.; Fredslund Andersen, M.; Brogaard, K.; Jiang, C.; Arentoft, T.; Grundahl, F.; Kjeldsen, H.; Christensen-Dalsgaard, J.; Weiss, E.; Pallé, P.; Antoci, V.; Kjærgaard, P.; Sørensen, A. N.; Skottfelt, J.; Jørgensen, U. G. Bibcode: 2018A&A...613A..53F Altcode: 2018arXiv180602095F Context. The Stellar Observation Network Group (SONG) is an initiative to build a worldwide network of 1m telescopes with high-precision radial-velocity spectrographs. Here we analyse the first radial-velocity time series of a red-giant star measured by the SONG telescope at Tenerife. The asteroseismic results demonstrate a major increase in the achievable precision of the parameters for red-giant stars obtainable from ground-based observations. Reliable tests of the validity of these results are needed, however, before the accuracy of the parameters can be trusted.
Aims: We analyse the first SONG time series for the star 46 LMi, which has a precise parallax and an angular diameter measured from interferometry, and therefore a good determination of the stellar radius. We use asteroseismic scaling relations to obtain an accurate mass, and modelling to determine the age.
Methods: A 55-day time series of high-resolution, high S/N spectra were obtained with the first SONG telescope. We derive the asteroseismic parameters by analysing the power spectrum. To give a best guess on the large separation of modes in the power spectrum, we have applied a new method which uses the scaling of Kepler red-giant stars to 46 LMi.
Results: Several methods have been applied: classical estimates, seismic methods using the observed time series, and model calculations to derive the fundamental parameters of 46 LMi. Parameters determined using the different methods are consistent within the uncertainties. We find the following values for the mass M (scaling), radius R (classical), age (modelling), and surface gravity (combining mass and radius): M = 1.09 ± 0.04M⊙, R = 7.95 ± 0.11R⊙ age t = 8.2 ± 1.9 Gy, and logg = 2.674 ± 0.013.
Conclusions: The exciting possibilities for ground-based asteroseismology of solar-like oscillations with a fully robotic network have been illustrated with the results obtained from just a single site of the SONG network. The window function is still a severe problem which will be solved when there are more nodes in the network.

Based on observations made with the Hertzsprung SONG telescope operated at the Spanish Observatorio del Teide on the island of Tenerife by the Aarhus and Copenhagen Universities and by the Instituto de Astrofísica de Canarias. Title: Low-frequency photospheric and wind variability in the early-B supergiant HD 2905 Authors: Simón-Díaz, S.; Aerts, C.; Urbaneja, M. A.; Camacho, I.; Antoci, V.; Fredslund Andersen, M.; Grundahl, F.; Pallé, P. L. Bibcode: 2018A&A...612A..40S Altcode: 2017arXiv171108994S Context. Despite important advances in space asteroseismology during the last decade, the early phases of evolution of stars with masses above 15 M⊙ (including the O stars and their evolved descendants, the B supergiants) have been only vaguely explored up to now. This is due to the lack of adequate observations for a proper characterization of the complex spectroscopic and photometric variability occurring in these stars. Aim. Our goal is to detect, analyze, and interpret variability in the early-B-type supergiant HD 2905 (κ Cas, B1 Ia) using long-term, ground-based, high-resolution spectroscopy.
Methods: We gather a total of 1141 high-resolution spectra covering some 2900 days with three different high-performance spectrographs attached to 1-2.6m telescopes at the Canary Islands observatories. We complement these observations with the hipparcos light curve, which includes 160 data points obtained during a time span of 1200 days. We investigate spectroscopic variability of up to 12 diagnostic lines by using the zero and first moments of the line profiles. We perform a frequency analysis of both the spectroscopic and photometric dataset using Scargle periodograms. We obtain single snapshot and time-dependent information about the stellar parameters and abundances by means of the FASTWIND stellar atmosphere code.
Results: HD 2905 is a spectroscopic variable with peak-to-peak amplitudes in the zero and first moments of the photospheric lines of up to 15% and 30 km s-1, respectively. The amplitude of the line-profile variability is correlated with the line formation depth in the photosphere and wind. All investigated lines present complex temporal behavior indicative of multi-periodic variability with timescales of a few days to several weeks. No short-period (hourly) variations are detected. The Scargle periodograms of the hipparcos light curve and the first moment of purely photospheric lines reveal a low-frequency amplitude excess and a clear dominant frequency at 0.37 d-1. In the spectroscopy, several additional frequencies are present in the range 0.1-0.4 d-1. These may be associated with heat-driven gravity modes, convectively driven gravity waves, or sub-surface convective motions. Additional frequencies are detected below 0.1 d-1. In the particular case of Hα, these are produced by rotational modulation of a non-spherically symmetric stellar wind.
Conclusions: Combined long-term uninterrupted space photometry with high-precision spectroscopy is the best strategy to unravel the complex low-frequency photospheric and wind variability of B supergiants. Three-dimensional (3D) simulations of waves and of convective motions in the sub-surface layers can shed light on a unique interpretation of the variability. 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: Photospheric activity of the Sun with VIRGO and GOLF. Comparison with standard activity proxies Authors: Salabert, D.; García, R. A.; Jiménez, A.; Bertello, L.; Corsaro, E.; Pallé, P. L. Bibcode: 2017A&A...608A..87S Altcode: 2017arXiv170905110S We study the variability of solar activity using new photospheric proxies originally developed for the analysis of stellar magnetism with the CoRoT and Kepler photometric observations. These proxies were obtained by tracking the temporal modulations in the observations associated with the spots and magnetic features as the Sun rotates. We analyzed 21 yr of observations, spanning solar cycles 23 and 24, collected by the space-based photometric VIRGO and radial velocity GOLF instruments on board the SoHO satellite. We then calculated the photospheric activity proxy Sph is for each of the three VIRGO photometers and the associated Svel proxy from the radial velocity GOLF observations. Comparisons with several standard solar activity proxies sensitive to different layers of the Sun demonstrate that these new activity proxies, Sph and Svel, provide a new manner to monitor solar activity. We show that both the long- and short-term magnetic variabilities respectively associated with the 11-yr cycle and the quasi-biennial oscillation are well monitored, and that the magnetic field interaction between the subsurface, photosphere, and chromosphere of the Sun was modified between Cycle 24 and Cycle 23. Furthermore, the photometric proxies show a wavelength dependence of the response function of the solar photosphere among the three channels of the VIRGO photometers, providing inputs for the study of the stellar magnetism of Sun-like stars. Title: Asteroseismic masses of retired planet-hosting A-stars using SONG Authors: Stello, Dennis; Huber, Daniel; Grundahl, Frank; Lloyd, James; Ireland, Mike; Casagrande, Luca; Fredslund, Mads; Bedding, Timothy R.; Palle, Pere L.; Antoci, Victoria; Kjeldsen, Hans; Christensen-Dalsgaard, Jørgen Bibcode: 2017MNRAS.472.4110S Altcode: 2017arXiv170809613S To better understand how planets form, it is important to study planet occurrence rates as a function of stellar mass. However, estimating masses of field stars is often difficult. Over the past decade, a controversy has arisen about the inferred occurrence rate of gas-giant planets around evolved intermediate-mass stars - the so-called 'retired A-stars'. The high masses of these red-giant planet hosts, derived using spectroscopic information and stellar evolution models, have been called into question. Here, we address the controversy by determining the masses of eight evolved planet-hosting stars using asteroseismology. We compare the masses with spectroscopic-based masses from the Exoplanet Orbit Database,which were previously adopted to infer properties of the exoplanets and their hosts. We find a significant one-sided offset between the two sets of masses for stars with spectroscopic masses above roughly 1.6 M⊙, suggestive of an average 15-20 per cent overestimate of the adopted spectroscopic-based masses. The only star in our sample well below this mass limit is also the only one not showing this offset. Finally, we note that the scatter across literature values of spectroscopic-based masses often exceeds their formal uncertainties, making it comparable to the offset we report here. Title: Promoting access to and use of seismic data in a large scientific community. SpaceInn data handling and archiving Authors: Michel, Eric; Belkacem, Kevin; Samadi, Reza; Assis Peralta, Raphael de; Renié, Christian; Abed, Mahfoudh; Lin, Guangyuan; Christensen-Dalsgaard, Jørgen; Houdek, Günter; Handberg, Rasmus; Gizon, Laurent; Burston, Raymond; Nagashima, Kaori; Pallé, Pere; Poretti, Ennio; Rainer, Monica; Mistò, Angelo; Panzera, Maria Rosa; Roth, Markus Bibcode: 2017EPJWC.16001011M Altcode: The growing amount of seismic data available from space missions (SOHO, CoRoT, Kepler, SDO,…) but also from ground-based facilities (GONG, BiSON, ground-based large programmes…), stellar modelling and numerical simulations, creates new scientific perspectives such as characterizing stellar populations in our Galaxy or planetary systems by providing model-independent global properties of stars such as mass, radius, and surface gravity within several percent accuracy, as well as constraints on the age. These applications address a broad scientific community beyond the solar and stellar one and require combining indices elaborated with data from different databases (e.g. seismic archives and ground-based spectroscopic surveys). It is thus a basic requirement to develop a simple and effcient access to these various data resources and dedicated tools. In the framework of the European project SpaceInn (FP7), several data sources have been developed or upgraded. The Seismic Plus Portal has been developed, where synthetic descriptions of the most relevant existing data sources can be found, as well as tools allowing to localize existing data for given objects or period and helping the data query. This project has been developed within the Virtual Observatory (VO) framework. In this paper, we give a review of the various facilities and tools developed within this programme. The SpaceInn project (Exploitation of Space Data for Innovative Helio- and Asteroseismology) has been initiated by the European Helio- and Asteroseismology Network (HELAS). Title: Atmospheric Extinction Coefficients in the Ic Band for Several Major International Observatories: Results from the BiSON Telescopes, 1984-2016 Authors: Hale, S. J.; Chaplin, W. J.; Davies, G. R.; Elsworth, Y. P.; Howe, R.; Lund, M. N.; Moxon, E. Z.; Thomas, A.; Pallé, P. L.; Rhodes, E. J., Jr. Bibcode: 2017AJ....154...89H Altcode: 2017arXiv170706647H Over 30 years of solar data have been acquired by the Birmingham Solar Oscillations Network (BiSON), an international network of telescopes used to study oscillations of the Sun. Five of the six BiSON telescopes are located at major observatories. The observational sites are, in order of increasing longitude: Mount Wilson (Hale) Observatory (MWO), California, USA; Las Campanas Observatory, Chile; Observatorio del Teide, Izaña, Tenerife, Canary Islands; the South African Astronomical Observatory, Sutherland, South Africa; Carnarvon, Western Australia; and the Paul Wild Observatory, Narrabri, New South Wales, Australia. The BiSON data may be used to measure atmospheric extinction coefficients in the {{{I}}}{{c}} band (approximately 700-900 nm), and presented here are the derived atmospheric extinction coefficients from each site over the years 1984-2016. Title: Kepler sheds new and unprecedented light on the variability of a blue supergiant: Gravity waves in the O9.5Iab star HD 188209 Authors: Aerts, C.; Símon-Díaz, S.; Bloemen, S.; Debosscher, J.; Pápics, P. I.; Bryson, S.; Still, M.; Moravveji, E.; Williamson, M. H.; Grundahl, F.; Fredslund Andersen, M.; Antoci, V.; Pallé, P. L.; Christensen-Dalsgaard, J.; Rogers, T. M. Bibcode: 2017A&A...602A..32A Altcode: 2017arXiv170301514A Stellar evolution models are most uncertain for evolved massive stars. Asteroseismology based on high-precision uninterrupted space photometry has become a new way to test the outcome of stellar evolution theory and was recently applied to a multitude of stars, but not yet to massive evolved supergiants.Our aim is to detect, analyse and interpret the photospheric and wind variability of the O9.5 Iab star HD 188209 from Kepler space photometry and long-term high-resolution spectroscopy. We used Kepler scattered-light photometry obtained by the nominal mission during 1460 d to deduce the photometric variability of this O-type supergiant. In addition, we assembled and analysed high-resolution high signal-to-noise spectroscopy taken with four spectrographs during some 1800 d to interpret the temporal spectroscopic variability of the star. The variability of this blue supergiant derived from the scattered-light space photometry is in full in agreement with the one found in the ground-based spectroscopy. We find significant low-frequency variability that is consistently detected in all spectral lines of HD 188209. The photospheric variability propagates into the wind, where it has similar frequencies but slightly higher amplitudes. The morphology of the frequency spectra derived from the long-term photometry and spectroscopy points towards a spectrum of travelling waves with frequency values in the range expected for an evolved O-type star. Convectively-driven internal gravity waves excited in the stellar interior offer the most plausible explanation of the detected variability.

Based on photometric observations made with the NASA Kepler satellite and on spectroscopic observations made with four telescopes: the Nordic Optical Telescope operated by NOTSA and the Mercator Telescope operated by the Flemish Community, both at the Observatorio del Roque de los Muchachos (La Palma, Spain) of the Instituto de Astrofísica de Canarias, the T13 2.0 m Automatic Spectroscopic Telescope (AST) operated by Tennessee State University at the Fairborn Observatory, and the Hertzsprung SONG telescope operated on the Spanish Observatorio del Teide on the island of Tenerife by the Aarhus and Copenhagen Universities and by the Instituto de Astrofísica de Canarias, Spain. Title: Lithium abundance and rotation of seismic solar analogues. Solar and stellar connection from Kepler and Hermes observations Authors: Beck, P. G.; do Nascimento, J. -D., Jr.; Duarte, T.; Salabert, D.; Tkachenko, A.; Mathis, S.; Mathur, S.; García, R. A.; Castro, M.; Pallé, P. L.; Egeland, R.; Montes, D.; Creevey, O.; Andersen, M. F.; Kamath, D.; van Winckel, H. Bibcode: 2017A&A...602A..63B Altcode: 2017arXiv170201152B Context. Lithium abundance A(Li) and surface rotation are good diagnostic tools to probe the internal mixing and angular momentum transfer in stars.
Aims: We explore the relation between surface rotation, A(Li), and age in a sample of seismic solar-analogue stars, and we study their possible binary nature.
Methods: We selected a sample of 18 solar-analogue stars observed by the NASA Kepler satellite for an in-depth analysis. Their seismic properties and surface rotation rates are well constrained from previous studies. About 53 h of high-resolution spectroscopy were obtained to derive fundamental parameters from spectroscopy and A(Li). These values were combined and compared with seismic masses, radii, and ages, as well as with surface rotation periods measured from Kepler photometry.
Results: Based on radial velocities, we identify and confirm a total of six binary star systems. For each star, a signal-to-noise ratio of 80 ≲ S/N ≲ 210 was typically achieved in the final spectrum around the lithium line. We report fundamental parameters and A(Li). Using the surface rotation period derived from Kepler photometry, we obtained a well-defined relation between A(Li) and rotation. The seismic radius translates the surface rotation period into surface velocity. With models constrained by the characterisation of the individual mode frequencies for single stars, we identify a sequence of three solar analogues with similar mass ( 1.1 M⊙) and stellar ages ranging between 1 to 9 Gyr. Within the realistic estimate of 7% for the mass uncertainty, we find a good agreement between the measured A(Li) and the predicted A(Li) evolution from a grid of models calculated with the Toulouse-Geneva stellar evolution code, which includes rotational internal mixing, calibrated to reproduce solar chemical properties. We found a scatter in ages inferred from the global seismic parameters that is too large when compared with A(Li).
Conclusions: We present the Li-abundance for a consistent spectroscopic survey of solar-analogue stars with a mass of 1.00 ± 0.15 M⊙ that are characterised through asteroseismology and surface rotation rates based on Kepler observations. The correlation between A(Li) and Prot supports the gyrochronological concept for stars younger than the Sun and becomes clearer when the confirmed binaries are excluded. The consensus between measured A(Li) for solar analogues with model grids, calibrated on the Sun's chemical properties, suggests that these targets share the same internal physics. In this light, the solar Li and rotation rate appear to be normal for a star like the Sun.

Based on observations made with the NASA Kepler space telescope and the Hermes spectrograph mounted on the 1.2 m Mercator Telescope at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias. Title: First Results from the Hertzsprung SONG Telescope: Asteroseismology of the G5 Subgiant Star μ Herculis Authors: Grundahl, F.; Fredslund Andersen, M.; Christensen-Dalsgaard, J.; Antoci, V.; Kjeldsen, H.; Handberg, R.; Houdek, G.; Bedding, T. R.; Pallé, P. L.; Jessen-Hansen, J.; Silva Aguirre, V.; White, T. R.; Frandsen, S.; Albrecht, S.; Andersen, M. I.; Arentoft, T.; Brogaard, K.; Chaplin, W. J.; Harpsøe, K.; Jørgensen, U. G.; Karovicova, I.; Karoff, C.; Kjærgaard Rasmussen, P.; Lund, M. N.; Sloth Lundkvist, M.; Skottfelt, J.; Norup Sørensen, A.; Tronsgaard, R.; Weiss, E. Bibcode: 2017ApJ...836..142G Altcode: 2017arXiv170103365G We report the first asteroseismic results obtained with the Hertzsprung Stellar Observations Network Group Telescope from an extensive high-precision radial-velocity observing campaign of the subgiant μ Herculis. The data set was collected during 215 nights in 2014 and 2015. We detected a total of 49 oscillation modes with l values from zero to three, including some l = 1 mixed modes. Based on the rotational splitting observed in l = 1 modes, we determine a rotational period of 52 days and a stellar inclination angle of 63°. The parameters obtained through modeling of the observed oscillation frequencies agree very well with independent observations and imply a stellar mass between 1.11 and 1.15 M ⊙ and an age of {7.8}-0.4+0.3 Gyr. Furthermore, the high-quality data allowed us to determine the acoustic depths of the He II ionization layer and the base of the convection zone.

Based on observations made with the Hertzsprung SONG telescope operated on the Spanish Observatorio del Teide on the island of Tenerife by the Aarhus and Copenhagen Universities and by the Instituto de Astrofísica de Canarias. Title: The SONG prototype: Efficiency of a robotic telescope Authors: Andersen, M. F.; Grundahl, F.; Beck, A. H.; Pallé, P. Bibcode: 2016RMxAC..48...54A Altcode: 2019arXiv190108293A The Stellar Observations Network Group prototype telescope at the Teide Observatory has been operating in scientific mode since March 2014. The first year of observations has entirely been carried out using the high resolution echelle spectrograph. Several asteroseismic targets were selected for scientific and technical verification. A few bright subgiants and one red giant were chosen since the oscillations in these stars have large amplitudes and the periods long enough to easily be detected. These targets would also be used for evaluation of the instruments since long term observations of single targets would reveal potential problems. In this paper the performance of the first robotic SONG node is described to illustrate the efficiency and possibilities in having a robotic telescope. Title: Photospheric and chromospheric magnetic activity of seismic solar analogs. Observational inputs on the solar-stellar connection from Kepler and Hermes Authors: Salabert, D.; García, R. A.; Beck, P. G.; Egeland, R.; Pallé, P. L.; Mathur, S.; Metcalfe, T. S.; do Nascimento, J. -D., Jr.; Ceillier, T.; Andersen, M. F.; Triviño Hage, A. Bibcode: 2016A&A...596A..31S Altcode: 2016arXiv160801489S We identify a set of 18 solar analogs among the seismic sample of solar-like stars observed by the Kepler satellite rotating between 10 and 40 days. This set is constructed using the asteroseismic stellar properties derived using either the global oscillation properties or the individual acoustic frequencies. We measure the magnetic activity properties of these stars using observations collected by the photometric Kepler satellite and by the ground-based, high-resolution Hermes spectrograph mounted on the Mercator telescope. The photospheric (Sph) and chromospheric (S index) magnetic activity levels of these seismic solar analogs are estimated and compared in relation to the solar activity. We show that the activity of the Sun is comparable to the activity of the seismic solar analogs, within the maximum-to-minimum temporal variations of the 11-yr solar activity cycle 23. In agreement with previous studies, the youngest stars and fastest rotators in our sample are actually the most active. The activity of stars older than the Sun seems to not evolve much with age. Furthermore, the comparison of the photospheric, Sph, with the well-established chromospheric, S index, indicates that the Sph index can be used to provide a suitable magnetic activity proxy which can be easily estimated for a large number of stars from space photometric observations.

Based on observations collected by the NASA Kepler space telescope and the Hermes spectrograph mounted on the 1.2 m Mercator telescope at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias. Title: Probing Seismic Solar Analogues Through Observations With The NASA Kepler Space Telescope and Hermes High-Resolution Spectrograph Authors: Beck, P. G.; Salabert, D.; Garcia, R. A.; do Nascimento, J., Jr.; Duarte, T. S. S.; Mathis, S.; Regulo, C.; Ballot, J.; Egeland, R.; Castro, M.; Pérez-Herńandez, F.,; Creevey, O.; Tkachenko, A.; van Reeth, T.; Bigot, L.; Corsaro, E.; Metcalfe, T.; Mathur, S.; Palle, P. L.; Allende Prieto, C.; Montes, D.; Johnston, C.; Andersen, M. F.; van Winckel, H. Bibcode: 2016csss.confE..42B Altcode: 2016arXiv161104329B Stars similar to the Sun, known as solar analogues, provide an excellent opportunity to study the preceding and following evolutionary phases of our host star. The unprecedented quality of photometric data collected by the Kepler NASA mission allows us to characterise solar-like stars through asteroseismology and study diagnostics of stellar evolution, such as variation of magnetic activity, rotation and the surface lithium abundance. In this project, presented in a series of papers by Salabert et al (2016ab) and Beck et al. (2016ab), we investigate the link between stellar activity, rotation, lithium abundance and oscillations in a group of 18 solar-analogue stars through space photometry, obtained with the NASA Kepler space telescope and from currently 50+ hours of ground-based, high-resolution spectroscopy with the Hermes instrument. In these proceedings, we first discuss the selection of the stars in the sample, observations and calibrations and then summarise the main results of the project.
By investigating the chromospheric and photospheric activity of the solar analogues in this sample, it was shown that for a large fraction of these stars the measured activity levels are compatible to levels of the 11-year solar activity cycle 23. A clear correlation between the lithium abundance and surface rotation was found for rotation periods shorter than the solar value. Comparing the lithium abundance measured in the solar analogues to evolutionary models with the Toulouse-Geneva Evolutionary Code (TGEC), we found that the solar models calibrated to the Sun also correctly describe the set of solar/stellar analogs showing that they share the same internal mixing physics. Finally, the star KIC3241581 and KIC10644353 are discussed in more detail. Title: The Solar-Stellar Connection: Magnetic Activity Of Seismic Solar Analogs Authors: Salabert, David; Garcia, Rafael A.; Beck, Paul G.; Regulo, C.; Ballot, J.; Creevey, Orlagh L.; Egeland, Ricky; do Nascimento, Jose-D., Jr.; Perez Hernandez, Fernando; Bigot, Lionel; Mathur, Savita; Metcalfe, Travis S.; Corsaro, Enrico; Palle, Pere L. Bibcode: 2016csss.confE..30S Altcode: 2016arXiv161000990S Finding solar-analog stars with fundamental properties as close as possible to the Sun and studying the characteristics of their surface magnetic activity is a very promising way to understand the solar variability and its associated dynamo process. However, the identification of solar-analog stars depends on the accuracy of the estimated stellar parameters. Thanks to the photometric CoROT and Kepler space missions, the addition of asteroseismic data was proven to provide the most accurate fundamental properties that can be derived from stellar modeling today. Here, we present our latest results on the solar-stellar connection by studying 18 solar analogs that we identified among the Kepler seismic sample (Salabert et al., 2016a}. We measured their magnetic activity properties using the observations collected by the Kepler satellite and the ground-based, high-resolution HERMES spectrograph. The photospheric (Sph) and chromospheric (S) magnetic activity proxies of these seismic solar analogs are compared in relation to the solar activity. We show that the activity of the Sun is comparable to the activity of the seismic solar analogs, within the maximum-to-minimum temporal variations of the 11-year solar activity cycle. Furthermore, we report on the discovery of temporal variability in the acoustic frequencies of the young (1 Gyr-old) solar analog KIC10644253 with a modulation of about 1.5 years, which agrees with the derived photospheric activity Sph (Salabert et al., 2016b}. It could be the signature of the short-period modulation, or quasi-biennal oscillation, of its magnetic activity as observed in the Sun and in the 1-Gyr-old solar analog HD30495. In addition, the lithium abundance and the chromospheric activity estimated from HERMES confirms that KIC10644253 is a young and more active star than the Sun. Title: Probing Stellar Dynamics With Space Photometry Authors: García, Rafael A.; Salabert, D.; Ballot, J.; Beck, P. G.; Bigot, L.; Corsaro, E.; Creevey, O.; Egeland, R.; Jiménez, A.; Mathur, S.; Metcalfe, T.; do Nascimento, J.; Pallé, P. L.; Pérez Hernández, F.; Regulo, C. Bibcode: 2016csss.confE...3G Altcode: The surface magnetic field has substantial influence on various stellar properties that can be probed through various techniques. With the advent of new space-borne facilities such as CoRoT and Kepler, uninterrupted long high-precision photometry is available for hundred of thousand of stars. This number will substantially grow through the forthcoming TESS and PLATO missions. The unique Kepler observations -covering up to 4 years with a 30-min cadence- allows studying stellar variability with different origins such as pulsations, convection, surface rotation, or magnetism at several time scales from hours to years. We study the photospheric magnetic activity of solar-like stars by means of the variability induced in the observed signal by starspots crossing the visible disk. We constructed a solar photometric magnetic activity proxy, Sph from SPM/VIRGO/SoHO, as if the Sun was a distant star and we compare it with several solar well-known magnetic proxies. The results validate this approach. Thus, we compute the Sph proxy for a set of CoRoT and Kepler solar-like stars for which pulsations were already detected. After characterizing the rotation and the magnetic properties of 300 solar-like stars, we use their seismic properties to characterize 18 solar analogs for which we study their magnetism. This allows us to put the Sun into context of its siblings. Title: Magnetic variability in the young solar analog KIC 10644253. Observations from the Kepler satellite and the HERMES spectrograph Authors: Salabert, D.; Régulo, C.; García, R. A.; Beck, P. G.; Ballot, J.; Creevey, O. L.; Pérez Hernández, F.; do Nascimento, J. -D., Jr.; Corsaro, E.; Egeland, R.; Mathur, S.; Metcalfe, T. S.; Bigot, L.; Ceillier, T.; Pallé, P. L. Bibcode: 2016A&A...589A.118S Altcode: 2016arXiv160300655S The continuous photometric observations collected by the Kepler satellite over 4 yr provide a wealth of data with an unequalled quantity and quality for the study of stellar evolution of more than 200 000 stars. Moreover, the length of the dataset provides a unique source of information for detecting magnetic activity and associated temporal variability in the acoustic oscillations. In this regards, the Kepler mission was awaited with great expectations. The search for the signature of magnetic activity variability in solar-like pulsations still remained unfruitful more than 2 yr after the end of the nominal mission. Here, however, we report the discovery of temporal variability in the low-degree acoustic frequencies of the young (1 Gyr-old) solar analog KIC 10644253 with a modulation of about 1.5 yr with significant temporal variations for the duration of the Kepler observations. The variations agree with the derived photometric activity. The frequency shifts extracted for KIC 10644253 are shown to result from the same physical mechanisms involved in the inner subsurface layers as in the Sun. In parallel, a detailed spectroscopic analysis of KIC 10644253 is performed based on complementary ground-based, high-resolution observations collected by the HERMES instrument mounted on the Mercator telescope. Its lithium abundance and chromospheric activity 𝒮 index confirm that KIC 10644253 is a young and more active star than the Sun. Title: Long-Term Trends and Gleissberg Cycles in Aurora Borealis Records (1600 - 2015) Authors: Vázquez, M.; Vaquero, J. M.; Gallego, M. C.; Roca Cortés, T.; Pallé, P. L. Bibcode: 2016SoPh..291..613V Altcode: 2016SoPh..tmp...12V The long-term spatial and temporal variation of aurora borealis events from 1600 to the present were studied using catalogues and other records of these phenomena. Geographic and geomagnetic coordinates were assigned to approximately 45 000 auroral events with more than 160 000 observations. They were analysed separately for three large-scale areas: i) Europe and North Africa, ii) North America, and iii) Asia. Variations in the cumulative numbers of auroral events with latitude (in both geographic and geomagnetic coordinates) were used to distinguish between the two main solar sources: coronal mass ejections and high-speed streams from coronal holes. We find significant long-term variations in the space-time distribution of auroras. We mainly identify these with four Gleissberg solar activity cycles whose overall characteristics we examine. The Asian observations are crucial in this context, and therefore merit further studies and verifications. 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: The two-colour EMCCD instrument for the Danish 1.54 m telescope and SONG Authors: Skottfelt, J.; Bramich, D. M.; Hundertmark, M.; Jørgensen, U. G.; Michaelsen, N.; Kjærgaard, P.; Southworth, J.; Sørensen, A. N.; Andersen, M. F.; Andersen, M. I.; Christensen-Dalsgaard, J.; Frandsen, S.; Grundahl, F.; Harpsøe, K. B. W.; Kjeldsen, H.; Pallé, P. L. Bibcode: 2015A&A...574A..54S Altcode: 2014arXiv1411.7401S We report on the implemented design of a two-colour instrument based on electron-multiplying CCD (EMCCD) detectors. This instrument is currently installed at the Danish 1.54 m telescope at ESO's La Silla Observatory in Chile, and will be available at the SONG (Stellar Observations Network Group) 1m telescope node at Tenerife and at other SONG nodes as well. We present the software system for controlling the two-colour instrument and calibrating the high frame-rate imaging data delivered by the EMCCD cameras. An analysis of the performance of the Two-Colour Instrument at the Danish telescope shows an improvement in spatial resolution of up to a factor of two when doing shift-and-add compared with conventional imaging, and the possibility of doing high-precision photometry of EMCCD data in crowded fields. The Danish telescope, which was commissioned in 1979, is limited by a triangular coma at spatial resolutions below 0.5 arcsec, and better results will thus be achieved at the near diffraction-limited optical system on the SONG telescopes, where spatial resolutions close to 0.2 arcsec have been achieved. Regular EMCCD operations have been running at the Danish telescope for several years and produced a number of scientific discoveries, including microlensing detected exoplanets, detecting previously unknown variable stars in dense globular clusters, and discovering two rings around the small asteroid-like object (10199) Chariklo.

Based on data collected with the Danish 1.54m telescope at ESO's La Silla Observatory. Title: Hardware and software for a robotic network of telescopes - SONG Authors: Andersen, M. F.; Grundahl, F.; Christensen-Dalsgaard, J.; Frandsen, S.; Jørgensen, U. G.; Kjeldsen, H.; Pallé, P.; Skottfelt, J.; Sørensen, A. N.; Weiss, E. Bibcode: 2014RMxAC..45...83A Altcode: 2019arXiv190108300A SONG aims at setting up a network of small 1m telescopes around the globe to observe stars uninterrupted throughout days, weeks and even months. This paper describes the fundamental aspects for putting up such a network and how we will operate each site as part of the full network. The SONG observatories will be working autonomously and automatic and can be fully controlled remotely. Title: The Mark-I helioseismic experiment - I. Measurements of the solar gravitational redshift (1976-2013) Authors: Roca Cortés, T.; Pallé, P. L. Bibcode: 2014MNRAS.443.1837R Altcode: 2014arXiv1406.5944R The resonant scattering solar spectrophotometer `Mark-I', designed and build at the University of Birmingham (UK) and located at the Observatorio del Teide (Spain), has been continuously in operation for the past 38 years. During this period of time, it has provided high-precision measurements of the radial velocity of the Sun as a star, which has enabled the study of the small velocity fluctuations produced by the solar oscillations and the characterization of their spectrum. So far, it has been one of the pioneer experiments in the field of helioseismology and contributed to the development of that area. Moreover, because of its high-sensitivity and long-term instrumental stability, it also provides an accurate determination (to within a few parts in 103) of the absolute daily velocity offset, which contains the so-called solar gravitational red-shift. In this paper, results of the analysis of the measurements of this parameter over the whole period 1976-2013 are presented. The result of this series of measurements is 600.4 ± 0.8 m s-1 with an amplitude variation of ±5 m s-1, which is in anticorrelation with the phase of the solar activity cycle. The 5 per cent difference found with respect to the value predicted by the equivalence principle is probably due to the asymmetry of the solar spectral line used. Title: Impact on asteroseismic analyses of regular gaps in Kepler data Authors: García, R. A.; Mathur, S.; Pires, S.; Régulo, C.; Bellamy, B.; Pallé, P. L.; Ballot, J.; Barceló Forteza, S.; Beck, P. G.; Bedding, T. R.; Ceillier, T.; Roca Cortés, T.; Salabert, D.; Stello, D. Bibcode: 2014A&A...568A..10G Altcode: 2014arXiv1405.5374G Context. The NASA Kepler mission has observed more than 190 000 stars in the constellations of Cygnus and Lyra. Around 4 years of almost continuous ultra high-precision photometry have been obtained reaching a duty cycle higher than 90% for many of these stars. However, almost regular gaps due to nominal operations are present in the light curves on different time scales.
Aims: In this paper we want to highlight the impact of those regular gaps in asteroseismic analyses, and we try to find a method that minimizes their effect on the frequency domain.
Methods: To do so, we isolate the two main time scales of quasi regular gaps in the data. We then interpolate the gaps and compare the power density spectra of four different stars: two red giants at different stages of their evolution, a young F-type star, and a classical pulsator in the instability strip.
Results: The spectra obtained after filling the gaps in the selected solar-like stars show a net reduction in the overall background level, as well as a change in the background parameters. The inferred convective properties could change as much as ~200% in the selected example, introducing a bias in the p-mode frequency of maximum power. When asteroseismic scaling relations are used, this bias can lead to a variation in the surface gravity of 0.05 dex. Finally, the oscillation spectrum in the classical pulsator is cleaner than the original one. Title: Asteroseismology Authors: Pallé, Pere L.; Esteban, Cesar Bibcode: 2014aste.book.....P Altcode: Our understanding of stars has grown significantly due to recent advances in asteroseismology, the stellar analog of helioseismology, the study of the Sun's acoustic wave oscillations. Using ground-based and satellite observatories to measure the frequency spectra of starlight, researchers are able to probe beneath a star's surface and map its interior structure. This volume provides a wide-ranging and up-to-date overview of the theoretical, experimental, and analytical tools for carrying out front-line research in stellar physics using asteroseismological observations, tools, and inferences. Chapters from seven eminent scientists in residence at the twenty-second Canary Islands Winter School of Astrophysics examine the interior of our Sun relative to data collected from distant stars, how to measure the fundamental parameters of single field stars, diffusion processes, and the effects of rotation on stellar structures. The volume also provides detailed treatments of modeling and computing programs, providing astronomers and graduate students a practical, methods-based guide. Title: Stellar Observations Network Group: The prototype is nearly ready Authors: Grundahl, Frank; Christensen-Dalsgaard, Jørgen; Pallé, Pere L.; Andersen, Mads F.; Frandsen, Søren; Harpsøe, Kennet; Jørgensen, Uffe Gråe; Kjeldsen, Hans; Rasmussen, Per K.; Skottfelt, Jesper; Sørensen, Anton N.; Hage, Andrea Triviño Bibcode: 2014IAUS..301...69G Altcode: The prototype telescope and instruments for the Stellar Observations Network Group (SONG) are nearing completion at the Observatorio del Teide on Tenerife. In this contribution we describe the current status (autumn 2013) of the telescope and its instrumentation. Preliminary performance characteristics are presented for the high-resolution spectrograph based on daytime observations of the Sun and a 4 hour test series obtained for the sub-giant β Aquilae. 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: 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: Observations of the radial velocity of the Sun as measured with the novel SONG spectrograph: results from a 1-week campaign Authors: Pallé, P. L.; Grundahl, F.; Triviño Hage, A.; Christensen-Dalsgaard, J.; Frandsen, S.; García, R. A.; Uytterhoeven, K.; Andersen, M. F.; Rasmussen, P. K.; Sørensen, A. N.; Kjeldsen, H.; Spano, P.; Nilsson, H.; Hartman, H.; Jørgensen, U. G.; Skottfelt, J.; Harpsøe, K.; Andersen, M. I. Bibcode: 2013JPhCS.440a2051P Altcode: Deployment of the prototype node of the SONG project took place in April 2012 at Observatorio del Teide (Canary Islands). Its key instrument (echelle spectrograph) was installed and operational a few weeks later while its 1 m feeding telescope suffered a considerable delay to meet the required specifications. Using a fibre-feed, solar light could be fed to the spectrograph and we carried out a 1-week observing campaign in June 2012 to evaluate its performance for measuring precision radial velocities. In this work we present the first results of this campaign by comparing the sensitivity of the SONG spectrograph with other helioseismology reference instruments (Mark-I and GOLF) when simultaneous data are considered. Title: Secular measurements of the solar gravitational redshift (1976 - 2011) Authors: Pallé, P. L.; Roca Cortés, T. Bibcode: 2013hsa7.conf..750P Altcode: The solar spectrophotometer "Mark-I", located at the Observatorio del Teide and continuously operated for the latest 36, provides a high precision measurement of the radial velocity of the Sun-as-a-star which has enabled the study of the small velocity fluctuations produced by normal modes solar oscillations and the characterization of its spectrum. Furthermore, because of its high sensitivity and long term instrumental stability also provides a daily accurate determination (less than 1 m s^{-1}) of the daily radial velocity offset, the so-called "solar gravitational red-shift" (GRS). In the present work, first results of the analysis of this parameter over the whole period 1976-2011 are presented. Title: SONG-OT: The prototype SONG node at Tenerife Authors: Uytterhoeven, K.; Pallé, P. L.; Grundahl, F.; Frandsen, S.; Christensen-Dalsgaard, J.; Triviño Hage, A.; SONG Team Bibcode: 2012AN....333.1103U Altcode: The prototype SONG node, SONG-OT, is currently being installed and tested at Observatory del Teide on Tenerife. SONG will be a global network of 1-m robotic telescopes, equipped with a high-resolution échelle spectrograph and dual-colour lucky imaging cameras. The network will be devoted to the seismic study of bright stars and characterisation of low-mass planets. We present the current status of the network in general and the SONG-OT node in particular. Title: Presentation of the reduction pipeline of the SONG échelle spectrograph Authors: Triviño Hage, A.; Uytterhoeven, K.; Grundahl, F.; Pallé, P. L.; SONG Team Bibcode: 2012AN....333.1107T Altcode: We give an overview of the spectral reduction pipeline that will be used to process the data of the échelle spectrograph of the SONG-OT telescope node of the SONG (Stellar Observations Network Group) network on Tenerife. In particular, we focus on the iodine absorption cell technique to derive precise radial velocity measurements. The telescope and dome of SONG-OT were installed on 23 April 2012, and first light is foreseen this autumn. The reduction pipeline will be tested, optimized and improved when real stellar data will become available. Title: Solar Global Oscillations of Low-Degree modes (GOLD): The Status of the Multi-channel Resonance Spectrometer GOLF-NG Authors: Turck-Chièze, S.; Carton, P. -H.; Barrière, J. -C.; Pallé, P. L.; Robillot, J. -M.; Ballot, J.; Chenus, A. -C.; Daniel-Thomas, P.; Delbart, A.; García, R. A.; Granelli, R.; Lahonde-Hamdoun, C.; Loiseau, D.; Mathur, S.; Piret, Y.; Salabert, D.; Simoniello, R.; Davies, G. R. Bibcode: 2012ASPC..462..240T Altcode: Low-degree pulsation modes are the best way to scrutinize stellar cores. They also provide, due to their intrinsic nature, a way to follow varying activity in important subsurface layers. Following difficulties encountered with the Solar and Heliospheric Observatory (SoHO) in 1998, we study a new design that improves the detection at low and high frequencies in comparison with the Global Oscillations at Low Frequency (GOLF) instrument. It is based on a substantial increase in the counting rates to get better photon statistics, and a reduction of the solar turbulent noise in measuring simultaneously the Doppler velocity at 6-7 heights in the strong sodium spectral line. A prototype, GOLF-NG (GOLF New Generation), has been built with numerous laboratory checks of the performance and in situ solar measurements at Tenerife in 2008 and 2010. All the required specifications are now achieved, and so GOLD can be prepared for space observations with balloons or satellites. The substantial improvements allow an improved detection of weak signals at different frequencies and information on activity indicators, as the Na D lines are sensitive to the magnetic field between photosphere and chromosphere. Title: Fast Rotating Solar-like Stars Using Asteroseismic Datasets Authors: García, R. A.; Ceillier, T.; Campante, T. L.; Davies, G. R.; Mathur, S.; Suárez, J. C.; Ballot, J.; Benomar, O.; Bonanno, A.; Brun, A. S.; Chaplin, W. J.; Christensen-Dalsgaard, J.; Deheuvels, S.; Elsworth, Y.; Handberg, R.; Hekker, S.; Jiménez, A.; Karoff, C.; Kjeldsen, H.; Mathis, S.; Mosser, B.; Pallé, P. L.; Pinsonneault, M.; Régulo, C.; Salabert, D.; Silva Aguirre, V.; Stello, D.; Thompson, M. J.; Verner, G.; PE11 Team of Kepler WG#1 Bibcode: 2012ASPC..462..133G Altcode: 2011arXiv1109.6488G The NASA Kepler mission is providing an unprecedented set of asteroseismic data. In particular, short-cadence light-curves (∼ 60 s samplings), allow us to study solar-like stars covering a wide range of masses, spectral types and evolutionary stages. Oscillations have been observed in around 600 out of 2000 stars observed for one month during the survey phase of the Kepler mission. The measured light curves can present features related to the surface magnetic activity (starspots) and, thus we are able to obtain a good estimate of the surface (differential) rotation. In this work we establish the basis of such research and we show a potential method to find stars with fast surface rotation. Title: The Acoustic Cutoff Frequency of the Sun and the Solar Magnetic Activity Cycle Authors: Jiménez, A.; García, R. A.; Pallé, P. L. Bibcode: 2011ApJ...743...99J Altcode: 2011arXiv1109.3326J The acoustic cutoff frequency—the highest frequency for acoustic solar eigenmodes—is an important parameter of the solar atmosphere as it determines the upper boundary of the p-mode resonant cavities. At frequencies beyond this value, acoustic disturbances are no longer trapped but are traveling waves. Interference among them gives rise to higher-frequency peaks—the pseudomodes—in the solar acoustic spectrum. The pseudomodes are shifted slightly in frequency with respect to p-modes, making possible the use of pseudomodes to determine the acoustic cutoff frequency. Using data from the GOLF and VIRGO instruments on board the Solar and Heliospheric Observatory spacecraft, we calculate the acoustic cutoff frequency using the coherence function between both the velocity and intensity sets of data. By using data gathered by these instruments during the entire lifetime of the mission (1996 until the present), a variation in the acoustic cutoff frequency with the solar magnetic activity cycle is found. Title: The SONG project and the prototype node at Tenerife Authors: Uytterhoeven, K.; Palle, P. L.; Grundahl, F.; Frandsen, S.; Kjeldsen, H.; Christensen-Dalsgaard, J.; Fredslund Andersen, M.; Weiss, E.; Joergensen, U. G.; Rasmussen, P. K.; Soerensen, A. N.; Harpsoee, K.; Skottfelt, J. Bibcode: 2011arXiv1111.1834U Altcode: SONG (Stellar Observations Network Group) is a global network of 1-m class robotic telescopes that is under development. The SONG prototype will shortly be operational at Observatorio del Teide, Tenerife, and first light is expected by December 2011. The main scientific goals of the SONG project are asteroseismology of bright stars and follow-up and characterization of exo-planets by means of precise measurements of stellar surface motions and brightness variations. We present the Tenerife SONG node and its instruments. Title: The Observatorio del Teide welcomes SONG:the Stellar Observations Network Group Authors: Creevey, O. L.; Grundahl, F.; Pallé, P. L.; Gråe Jørgensen, U.; Belmonte, J. A.; Christensen-Dalsgaard, J.; Frandsen, S.; Kjeldsen, H.; Kjærgaard, P. Bibcode: 2011hsa6.conf..686C Altcode: 2011arXiv1112.5539C The Stellar Observations Network Group (SONG) is an internationalnetwork project aiming to place eight 1 m robotic telescopes around the globe,with the primary objectives of studying stellar oscillations and planetsusing ultra-precision radial velocity measurements.The prototype of SONG will be installed and running at the Observatoriodel Teide by Summer 2011. In these proceedings we present the project, primary scientific objectives, and instrument, and discussthe observing possibilities for the Spanish community. Title: The acoustic cutoff frequency of the Sun and the solar cycle Authors: Jiménez, A.; García, R. A.; Pallé, P. L. Bibcode: 2011JPhCS.271a2051J Altcode: The acoustic cutoff frequency - highest frequency for acoustic solar eigenmodes-is an important parameter of the solar atmosphere because it determines the upper boundary of the p mode cavities. At frequencies beyond this value, acoustic disturbances are no longer trapped waves but traveling waves. Interferences amongst them, originate higher frequency peaks -the pseudomodes- in the solar acoustic spectrum. Using data from GOLF and VIRGO instruments aboard SoHO spacecraft, we determine the acoustic cutoff frequency using the coherence function between both sets of data, velocity and intensity. By using data gathered by these instruments during the whole lifetime of the mission (1996 till present), it is found a variation of this parameter with the solar magnetic activity cycle. Title: New insights on the solar core Authors: García, R. A.; Salabert, D.; Ballot, J.; Eff-Darwich, A.; Garrido, R.; Jiménez, A.; Mathis, S.; Mathur, S.; Moya, A.; Pallé, P. L.; Régulo, C.; Sato, K.; Suárez, J. C.; Turck-Chièze, S. Bibcode: 2011JPhCS.271a2046G Altcode: 2010arXiv1012.0506G Since the detection of the asymptotic properties of the dipole gravity modes in the Sun, the quest to find individual gravity modes has continued. An extensive and deeper analysis of 14 years of continuous GOLF/SoHO observational data, unveils the presence of a pattern of peaks that could be interpreted as individual dipole gravity modes in the frequency range between 60 and 140 microHz, with amplitudes compatible with the latest theoretical predictions. By collapsing the power spectrum we have obtained a quite constant splitting for these patterns in comparison to regions where no g modes were expected. Moreover, the same technique applied to simultaneous VIRGO/SoHO data unveils some common signals between the power spectra of both instruments. Thus, we are able to identify and characterize individual g modes with their central frequencies, amplitudes and splittings allowing to do seismic inversions of the rotation profile inside the solar core. These results open a new ligh t on the physics and dynamics of the solar deep core. Title: Global p-mode oscillations throughout the complete solar cycle 23 and the beginning of cycle 24 Authors: Salabert, D.; García, R. A.; Pallé, P. L.; Jiménez, A. Bibcode: 2011JPhCS.271a2030S Altcode: 2010arXiv1011.4966S The parameters of the p-mode oscillations vary with solar activity. Such temporal variations provide insights for the study of the structural and dynamical changes occurring in the Sun's interior throughout the solar cycle. We present here a complete picture of the temporal variations of the global p-mode parameters (excitation, damping, frequency, peak asymmetry, and rotational splitting) over the entire solar cycle 23 and the beginning of cycle 24 as observed by the space-based, Sun-as-a-star helioseismic GOLF and VIRGO instruments onboard SoHO. Title: Four years of HELAS Authors: Roth, M.; Lühe, O. v. d.; Aerts, C.; Christensen-Dalsgaard, J.; Corbard, T.; Daszyńska-Daszkiewicz, J.; Di Mauro, M. P.; Gizon, L.; Jiménez-Reyes, S.; Monteiro, M. J. P. F. G.; Pallé, P. L.; Thompson, M. J. Bibcode: 2010AN....331.1084R Altcode: The European Coordination Action on HELio- and ASteroseismology (HELAS) has completed its fourth and final year of initial funding by the European Commission. Set up as a network which combines solar and stellar physics communities in the important and vigorously evolving field of seismology, HELAS has been able to coordinate the efforts of European astronomers with remarkable success. Four large international conferences including the HELAS-IV conference on Lanzarote as well as many workshops were organized with a substantial contribution from HELAS. About a dozen workshops, addressing specialized questions in global and local helioseismology and asteroseismology were entirely organized by HELAS. Data analysis tools to prepare the European communities for the upcoming influx of data from new missions have been prepared, tested and demonstrated. Lecture notes and outreach material have been assembled and prepared for general access. As a result, HELAS has an important impact on the scientific output of the astrophysics seismology communities and significantly increased the visibility of European research in this field. This paper summarizes the activities and accomplishments of HELAS. Title: Towards a detection of individual g modes in the Sun Authors: Garcia, R. A.; Ballot, J.; Eff-Darwich, A.; Garrido, R.; Jimenez, A.; Mathis, S.; Mathur, S.; Moya, A.; Palle, P. L.; Regulo, C.; Salabert, D.; Suarez, J. C.; Turck-Chieze, S. Bibcode: 2010arXiv1007.4445G Altcode: Since the detection of the asymptotic properties of the dipole gravity modes in the Sun, the quest to find the individual gravity modes has continued. A deeper analysis of the GOLF/SoHO data unveils the presence of a pattern of peaks that could be interpreted as individual dipole gravity modes. The computed collapsed spectrum -around these candidate modes- uncovers the presence of a quasi constant frequency splitting, in contrast with regions where no g modes are expected in which the collapsogram gives random results. Besides, the same technique applied to VIRGO/SoHO unveils some common signals between both power spectra. Thus, we can identify and characterize the modes, for example, with their central frequency and splittings. This would open the path towards new investigations to better constrain the solar core. Title: Frequency Shifts of the Individual Low-Degree P-Modes during Solar Cycle 23 and its Extended Minimum Authors: Salabert, D.; García, R. A.; Pallé, P. L.; Jiménez-Reyes, S. J. Bibcode: 2010ASPC..428...51S Altcode: 2010arXiv1003.4354S We study the response of the low-degree solar p-mode frequencies to the unusual extension of the minimum of solar surface activity since 2007. Helioseismic observations collected by the space-based, Sun-as-a-star GOLF instrument and by the ground-based, multi-site network GONG (integrated signal) are analyzed. Temporal variations of the low-degree (l=0,1,2), p-mode frequencies are obtained. Although the known correlation of the frequency changes with solar surface activity is recovered for the period 1996â??2007, since the second half of 2007 and until July 2009 (the latest period analyzed) we notice a peculiar behavior amongst modes of different angular degrees. In particular, a clear increase of the l=0 and l=2 p-mode frequencies is obtained consistently since late 2007, while the l=1 frequencies follow the general decreasing trend of surface activity. We interpret these differences in the frequency shifts of individual low-degree modes as indicative of variations at high latitudes in the magnetic flux beneath the surface of the Sun related to the onset of solar cycle 24. Title: SONG: an observational new facility at Observatorio del Teide for stellar observations Authors: Creevey, O.; Pallé, P. L.; Belmonte, J. A. Bibcode: 2010iac..talk..141C Altcode: 2010iac..talk..161C No abstract at ADS Title: The extended minimum of solar cycle 23 as seen by radial velocity (GOLF, GONG) and intensity (VIRGO) helioseismic instruments Authors: Salabert, D.; Garcia, R. A.; Palle, P. L.; Jimenez-Reyes, S. J.; Jimenez, A. Bibcode: 2010arXiv1004.2869S Altcode: We present an analysis of the variability of the solar oscillation spectrum during solar cycle 23 and its extended minimum. We use simultaneous observations of the low-degree solar p modes collected by the space-based, Sun-as-a-star GOLF (radial velocity) and VIRGO (intensity) instruments, and by the ground-based, multi-site network GONG. We investigate in particular the response of the p-mode eigenfrequencies to the observed peculiar deep solar minimum of surface activity of 2007-2009 as compared with the previous solar cycle 23. We study the different temporal variations of the p-mode frequencies with individual angular degrees. 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: Interior and Exterior Clues of Solar Activity Authors: Turck-Chièze, S.; Brun, A. S.; Duez, V.; García, R. A.; Mathis, S.; Piau, L.; Salabert, D.; Pallé, P. L.; Jiménez-Reyes, S. J.; Mathur, S.; Simoniello, R.; Robillot, J. M. Bibcode: 2010ASSP...19..368T Altcode: 2010mcia.conf..368T Two research paths are described to obtain better understanding of the origin of global solar activity. First, observations with a multichannel resonant spectrometer may reveal the dynamics of the solar core, the tachocline, and the temporal evolution of activity between the photosphere and chromosphere. Such new observations will deliver constraints for 3D simulations of solar activity. Second, we examine the ab-initio introduction of a non-force-free field expressed in spherical harmonics into the solar structure equations and estimate its impact on the inner and subsurface layers, its time evolution, and its role in angular momentum transport. Title: First Performance of the GOLF-NG Instrumental Prototype Observing the Sun in Tenerife Authors: Salabert, D.; Turck-Chièze, S.; Barrière, J. C.; Carton, P. H.; Daniel-Thomas, P.; Delbart, A.; García, R. A.; Granelli, R.; Jiménez-Reyes, S. J.; Lahonde-Hamdoun, C.; Loiseau, D.; Mathur, S.; Nunio, F.; Pallé, P. L.; Piret, Y.; Robillot, J. M.; Simoniello, R. Bibcode: 2009ASPC..416..341S Altcode: 2008arXiv0810.3393S The primary challenge of Global Oscillations at Low Frequency New Generation (GOLF-NG) is the detection of the low-frequency solar gravity and acoustic modes, as well as the possibility to measure the high-frequency chromospheric modes. On June 8th 2008, the first sunlight observations with the multichannel resonant GOLF-NG prototype spectrometer were obtained at the Observatorio del Teide (Tenerife). The instrument performs integrated (Sun-as-a-star), Doppler velocity measurements, simultaneously at eight different heights in the D1 sodium line profile, corresponding to photospheric and chromospheric layers of the solar atmosphere. In order to study its performance, to validate the conceived strategy, and to estimate the necessary improvements, this prototype has been running on a daily basis over the whole summer of 2008 at the Observatorio del Teide. We present here the results of the first GOLF-NG observations, clearly showing the characteristics of the 5-minute oscillatory signal at different heights in the solar atmosphere. We compare these signals with simultaneous observations from Global Oscillations at Low Frequency (GOLF)/SoHO and from the Mark-I instrument—a node of the Birmingham Solar Oscillations Network (BiSON) network, operating at the same site. Title: Detecting individual gravity modes in the Sun Authors: Garcia, R. A.; Ballot, J.; Eff-Darwich, A.; Garrido, R.; Jimenez, A.; Mathis, S.; Moya, A.; Palle, P. L.; Regulo, C.; Salabert, D.; Suarez, J. C.; Turck-Chieze, S. Bibcode: 2009arXiv0911.5442G Altcode: Many questions are still open regarding the structure and the dynamics of the solar core. By constraining more this region in the solar evolution models, we can reduce the incertitudes on some physical processes and on momentum transport mechanisms. A first big step was made with the detection of the signature of the dipole-gravity modes in the Sun, giving a hint of a faster rotation rate inside the core. A deeper analysis of the GOLF/SoHO data unveils the presence of a pattern of peaks that could be interpreted as dipole gravity modes. In that case, those modes can be characterized, thus bringing better constraints on the rotation of the core as well as some structural parameters such as the density at these very deep layers of the Sun interior. Title: HD 172189: another step in furnishing one of the best laboratories known for asteroseismic studies Authors: Creevey, O. L.; Uytterhoeven, K.; Martín-Ruiz, S.; Amado, P. J.; Niemczura, E.; van Winckel, H.; Suárez, J. C.; Rolland, A.; Rodler, F.; Rodríguez-López, C.; Rodríguez, E.; Raskin, G.; Rainer, M.; Poretti, E.; Pallé, P.; Molina, R.; Moya, A.; Mathias, P.; Le Guillou, L.; Hadrava, P.; Fabbian, D.; Garrido, R.; Decin, L.; Cutispoto, G.; Casanova, V.; Broeders, E.; Arellano Ferro, A.; Aceituno, F. Bibcode: 2009A&A...507..901C Altcode: 2009arXiv0909.3435C HD 172189 is a spectroscopic eclipsing binary system with a rapidly-rotating pulsating δ Scuti component. It is also a member of the open cluster IC 4756. These combined characteristics make it an excellent laboratory for asteroseismic studies. To date, HD 172189 has been analysed in detail photometrically but not spectroscopically. For this reason we have compiled a set of spectroscopic data to determine the absolute and atmospheric parameters of the components. We determined the radial velocities (RV) of both components using four different techniques. We disentangled the binary spectra using KOREL, and performed the first abundance analysis on both disentangled spectra. By combining the spectroscopic results and the photometric data, we obtained the component masses, 1.8 and 1.7 M⊙, and radii, 4.0 and 2.4 R⊙, for inclination i = 73.2°, eccentricity e = 0.28, and orbital period Π = 5.70198 days. Effective temperatures of 7600 K and 8100 K were also determined. The measured v sin i are 78 and 74 km s-1, respectively, giving rotational periods of 2.50 and 1.55 days for the components. The abundance analysis shows [Fe/H] = -0.28 for the primary (pulsating) star, consistent with observations of IC 4756. We also present an assessment of the different analysis techniques used to obtain the RVs and the global parameters. Title: The onset of solar cycle 24. What global acoustic modes are telling us Authors: Salabert, D.; García, R. A.; Pallé, P. L.; Jiménez-Reyes, S. J. Bibcode: 2009A&A...504L...1S Altcode: 2009arXiv0907.3888S We study the response of the low-degree, solar p-mode frequencies to the unusually extended minimum of solar surface activity since 2007. A total of 4768 days of observations collected by the space-based, Sun-as-a-star helioseismic GOLF instrument are analyzed. A multi-step iterative maximum-likelihood fitting method is applied to subseries of 365 days and 91.25 days to extract the p-mode parameters. Temporal variations in the l=0, 1, and 2 p-mode frequencies are then obtained from April 1996 to May 2009. While the p-mode frequency shifts are closely correlated with solar surface activity proxies during the past solar cycles, the frequency shifts of the l=0 and l=2 modes increase from the second half of 2007, when no significant surface activity is observable. On the other hand, the l=1 modes follow the general decreasing trend of solar surface activity. The different behaviors between the l=0 and l=2 modes and the l=1 modes may be interpreted as different geometrical responses to the spatial distribution of the solar magnetic field beneath the surface of the Sun. The analysis of the low-degree, solar p-mode frequency shifts indicates that the solar activity cycle 24 started in late 2007, despite the absence of activity on the solar surface. Title: The GOLF-NG prototype and the solar European perspective for cosmic vision 2015-2025 Authors: Turck-Chièze, Sylvaine; Mathur, Savita; Ballot, Jérome; García, Rafael A.; Carton, Pierre-Henri; Barrière, Jean-Christophe; Daniel-Thomas, Philippe; Delbart, Alain; Desforges, Daniel; Granelli, Rémi; Nunio, Francois; Piret, Yves; Pallé, Pere L.; Jiménez, Antonio J.; Jiménez-Reyes, Sébastian J.; Simoniello, Rosaria; Dyna MICCS Team Bibcode: 2008JPhCS.118a2044T Altcode: The progress on the dynamics of the radiative zone by global Doppler velocity measurements aboard SoHO (GOLF+ MDI) and with ground networks (BiSON and GONG) opens a new perspective for solar and stellar physics. It is why we prepare a new generation of solar resonant spectrometer. The objectives of the GOLF-NG instrument and its present status are described. We have demonstrated this year that most of the technical challenges have been successfully faced and the next steps are mentioned. We then recall the scientific questions that might be solved with the next generation of instruments in construction in different european laboratories to reach a complete 3D vision of our star from the core to the corona. Two formation flying missions DynaMICCS and HIRISE have been proposed to ESA in the framework of the 2015-2025 Cosmic Vision perspective to contribute to solve these questions. A strategy of measurements must be found for the next decade. Title: Preliminary results on the contribution of the convection motions to the Doppler velocity signal Authors: Simoniello, R.; Ruiz-Cobo, B.; Jiménez-Reyes, S. J.; García, R. A.; Pallé, P. L. Bibcode: 2008JPhCS.118a2089S Altcode: This investigation aims to study the correlation of the solar background with atmosphere. We used high resolution observations of the NaDl spectral line. In fact the large span in formation heights of this spectral line allowed us to infer the signal from photosphere to chromosphere. We analyzed the data by applying the SIR code (Stokes Inversion based on response functions). It is an inversion method of the RTE (Radiative transfer equation) that provides physical information on the region where the spectral lines are sensitive to changes in thermal and dynamical parameters of the atmosphere. The survey has been divided in two different steps: 1) identification of a model of the atmosphere that reproduce our observations; 2) determination of the degree of correlation of convective motions with the solar atmosphere. Here we present the results of the first step: we identified in the model presented by Vernazza the best model that matches our observations. Title: Update on g-mode research Authors: García, R. A.; Jiménez, A.; Mathur, S.; Ballot, J.; Eff-Darwich, A.; Jiménez-Reyes, S. J.; Pallé, P. L.; Provost, J.; Turck-Chièze, S. Bibcode: 2008AN....329..476G Altcode: 2008arXiv0802.4296G Since the beginning of this century we have attended a blooming of the gravity-mode research thanks to the unprecedented quality of the data available, either from space with SoHO, or from the ground-based networks as BiSON or GONG. From the first upper limit of the gravity-mode amplitudes fixed at 10 mm/s at 200 μHz given by Appourchaux et al. (2000), on one hand, a peak was supposed to be a component of the ℓ = 1, n = 1 mixed mode (García et al. 2001a, 2001b; Gabriel et al. 2002) and, on the other hand, a couple of patterns - multiplets - were attributed to gravity modes (Turck-Chièze et al. 2004; Mathur et al. 2007). One of these patterns, found around 220 μHz, could be labeled as the ℓ = 2, n =-3 g mode, which is expected to be the one with the highest surface amplitude (Cox & Guzik 2004). Finally, in 2007, García et al. were able to measure the fingertips of the dipole gravity modes looking for their asymptotic properties. In the present paper we present an update of the recent developments on this subject with special attention to the 220 μHz region, the dipole asymptotic properties and the impact of the incoming g-mode observations on the knowledge of the solar structure and rotation profile. Title: p-mode power variation with solar atmosphere as observed in the Na D1 and K spectral lines Authors: Simoniello, R.; Jiménez-Reyes, S. J.; García, R. A.; Pallé, P. L. Bibcode: 2008AN....329..494S Altcode: In this work we investigate p-mode power variation with solar atmosphere. To this aim, we use THÉMIS observations of the Na D1 (λ5896 Å) and K (λ7699 Å) spectral lines. While the formation heights of the K spectral line are essentially located in the photospheric layer, the formation heights of the Na D1 line span a much wider region: from photosphere up to chromosphere. Hence, we had the opportunity to infer p-mode power variation up to the chromospheric layer. By analyzing power spectra obtained by temporal series at different points of the Na D1 and K spectral lines, we confirm and quantify the increase in p-mode power towards higher atmospheric layers. Furthermore, the large span in formation heights of the Na D1 line induces a larger enhancement of p-mode power with solar atmosphere compared to the K spectral line. Title: HELAS IT-platform: A new tool for the European Helio- and Asteroseismology community. Authors: Jiménez-Reyes, S. J.; Quintero Nerkhorn, J.; Pallé, P. L.; Helas Board Bibcode: 2008CoAst.153..108J Altcode: HELAS is a Coordination Action funded under the European Commission's Sixth Framework Programme (FP6) since April 1st, 2006 till March 31st, 2010. The HELAS Consortium includes 10 partner institutions that host researchers active in helio- and asteroseismology. This initiative offers a unique chance to advance the field further by coordinating the activities of researchers, enhancing the quality and quantity of science performed in Europe. The HELAS Forum is one of its Networking Activities. Its main goal is to encourage, provide, and support the tools, activities, and initiatives emanating from the European helio- and asterosesimology scientific communities. Thus, the HELAS Forum should ensure European competence and competitiveness in these areas by better coordinating the groups. It also enhances the synergies between the helio- and astero communities and between those and other non-European related activities. Here, we present the Helas Forum IT-platform (www.helas-eu.org), developed to facilitate the coordinated activities such as data and software package exchange, information about workshops and meetings, knowledge of the community, etc., as well as to allow tracking the development of HELAS activities. Title: Tracking Solar Gravity Modes: The Dynamics of the Solar Core Authors: García, Rafael A.; Turck-Chièze, Sylvaine; Jiménez-Reyes, Sebastian J.; Ballot, Jérôme; Pallé, Pere L.; Eff-Darwich, Antonio; Mathur, Savita; Provost, Janine Bibcode: 2007Sci...316.1591G Altcode: Solar gravity modes have been actively sought because they directly probe the solar core (below 0.2 solar radius), but they have not been conclusively detected in the Sun because of their small surface amplitudes. Using data from the Global Oscillation at Low Frequency instrument, we detected a periodic structure in agreement with the period separation predicted by the theory for gravity dipole modes. When studied in relation to simulations including the best physics of the Sun determined through the acoustic modes, such a structure favors a faster rotation rate in the core than in the rest of the radiative zone. Title: The DynaMICS perspective Authors: Turck-Chièze, S.; Schmutz, W.; Thuillier, G.; Jefferies, S.; Pallé; Dewitt, S.; Ballot, J.; Berthomieu, G.; Bonanno, A.; Brun, A. S.; Christensen-Dalsgaard, J.; Corbard, T.; Couvidat, S.; Darwich, A. M.; Dintrans, B.; Domingo, V.; Finsterle, W.; Fossat, E.; Garcia, R. A.; Gelly, B.; Gough, D.; Guzik, J.; Jiménez, A. J.; Jiménez-Reyes, S.; Kosovichev, A.; Lambert, P.; Lefebvre, S.; Lopes, I.; Martic, M.; Mathis, S.; Mathur, S.; Nghiem, P. A. P.; Piau, L.; Provost, J.; Rieutord, M.; Robillot, J. M.; Rogers, T.; Roudier, T.; Roxburgh, I.; Rozelot, J. P.; Straka, C.; Talon, S.; Théado, S.; Thompson, M.; Vauclair, S.; Zahn, J. P. Bibcode: 2006ESASP.624E..24T Altcode: 2006soho...18E..24T No abstract at ADS Title: European helio- and asteroseismology network HELAS Authors: Roth, M.; Luhe, O. v. d.; Palle, P.; Thompson, M. J.; Christensen-Dalsgaard, J.; Monteiro, M. J. P. F. G.; Gizon, L.; Di Mauro, M. P.; Aerts, C.; Daszynska-Daszkiewicz, J.; Corbard, T. Bibcode: 2006ESASP.624E.130R Altcode: 2006soho...18E.130R The Helio- and Asteroseismology Network (HELAS) is a Coordinated Action funded by the FP6-Infrastructure-Programme of the European Commission. Currently, HELAS consists of ten members. The objective of HELAS is to co-ordinate European activities in helio- and asteroseismology. HELAS will transfer knowledge and data analysis techniques, and will prepare the European research community for important missions in the immediate future. Title: Detection of periodic signatures in the solar power spectrum On the track of l=1 gravity modes Authors: García, R. A.; Turck-Chièze, S.; Jiménez-Reyes, S. J.; Ballot, J.; Pallé, P. L.; Eff-Darwich, A.; Mathur, S.; Provost, J. Bibcode: 2006ESASP.624E..23G Altcode: 2006astro.ph.11806G; 2006soho...18E..23G In the present work we show robust indications of the existence of g modes in the Sun using 10 years of GOLF data. The present analysis is based on the exploitation of the collective properties of the predicted low-frequency (25 to 140 microHz) g modes: their asymptotic nature, which implies a quasi equidistant separation of their periods for a given angular degree (l). The Power Spectrum (PS) of the Power Spectrum Density (PSD), reveals a significant structure indicating the presence of features (peaks) in the PSD with near equidistant periods corresponding to l=1 modes in the range n=-4 to n=-26. The study of its statistical significance of this feature was fully undertaken and complemented with Monte Carlo simulations. This structure has a confidence level better than 99.86% not to be due to pure noise. Furthermore, a detailed study of this structure suggests that the gravity modes have a much more complex structure than the one initially expected (line-widths, magnetic splittings...). Compared to the latest solar models, the obtained results tend to favor a solar core rotating significantly faster than the rest of the radiative zone. In the framework of the Phoebus group, we have also applied the same methodology to other helioseismology instruments on board SoHO and ground based networks. Title: Knowledge of the solar core dynamics through g modes Authors: Garcia, R. A.; Turck-Chièze, S.; Jimenez-Reyes, S. J.; Ballot, J.; Pallé, P. L.; Eff-Darwich, A.; Mathur, S.; Provost, J. Bibcode: 2006IAUJD..17E...8G Altcode: Helioseismology is able to study the solar interior through the observation of the solar oscillation modes propagating inside the Sun. Pressure-driven modes (p modes) provide a very detailed picture of the external convective zone above 0.7 R[⊙]and the radiative zone down to ~0.2 R[⊙] where only a few of such modes penetrate so far. To study deeper layers, still containing more than 40% of the totals mass, another type of oscillations are needed: the gravity-driven modes (g modes). Since the early 19 80s, this type of mode has been looked for. Only very recently have we have found some structures that are compatible with some global properties of these modes in the GOLF/ SOHO data. In this contribution we will show these signals. By explaining them as the signature of the asymptotic properties of the ℓ = 1 g modes, we could start constraining the solar core dynamics. Title: Scientific Objectives of the Novel Formation Flying Mission Aspiics Authors: Turck-Chièze, S.; Schmutz, W.; Thuillier, G.; Jefferies, S.; Pallé; Dewitt, S.; Ballot, J.; Berthomieu, G.; Bonanno, A.; Brun, A. S.; Christensen-Dalsgaard, J.; Corbard, T.; Couvidat, S.; Darwich, A. M.; Dintrans, B.; Domingo, V.; Finsterle, W.; Fossat, E.; Garcia, R. A.; Gelly, B.; Gough, D.; Guzik, J.; Jiménez, A. J.; Jiménez-Reyes, S.; Kosovichev, A.; Lambert, P.; Lefebvre, S.; Lopes, I.; Martic, M.; Mathis, S.; Mathur, S.; Nghiem, P. A. P.; Piau, L.; Provost, J.; Rieutord, M.; Robillot, J. M.; Rogers, T.; Roudier, T.; Roxburgh, I.; Rozelot, J. P.; Straka, C.; Talon, S.; Théado, S.; Thompson, M.; Vauclair, S.; Zahn, J. P. Bibcode: 2006ESASP.617E.164L Altcode: 2006soho...17E.164L No abstract at ADS Title: The EUV Variability Experiment (EVE) on the Solar Dynamics Observatory (SDO): Science Plan and Instrument Overview Authors: Turck-Chièze, S.; Schmutz, W.; Thuillier, G.; Jefferies, S.; Pallé; Dewitt, S.; Ballot, J.; Berthomieu, G.; Bonanno, A.; Brun, A. S.; Christensen-Dalsgaard, J.; Corbard, T.; Couvidat, S.; Darwich, A. M.; Dintrans, B.; Domingo, V.; Finsterle, W.; Fossat, E.; Garcia, R. A.; Gelly, B.; Gough, D.; Guzik, J.; Jiménez, A. J.; Jiménez-Reyes, S.; Kosovichev, A.; Lambert, P.; Lefebvre, S.; Lopes, I.; Martic, M.; Mathis, S.; Mathur, S.; Nghiem, P. A. P.; Piau, L.; Provost, J.; Rieutord, M.; Robillot, J. M.; Rogers, T.; Roudier, T.; Roxburgh, I.; Rozelot, J. P.; Straka, C.; Talon, S.; Théado, S.; Thompson, M.; Vauclair, S.; Zahn, J. P. Bibcode: 2006ESASP.617E.165W Altcode: 2006soho...17E.165W No abstract at ADS Title: Detection of the Periodic Signatures of l=1 Solar g Modes with 10 Years of GOLF/SOHO Data Authors: Garcia, Rafael A.; Turck-Chiéze, Sylvaine; Jiménez-Reyes, Sebastián J.; Ballot, Jerome; Palle, Pere L.; Eff-Darwich, Antonio; Mathur, Savita; Provost, Janine Bibcode: 2006ESASP.617E...3G Altcode: 2006soho...17E...3G No abstract at ADS Title: Helas-European Helio- and Asteroseismology Network Authors: Roth, M.; Lühe, O. v. d.; Pallé, P.; Thompson, M.; Christensen-Dalsgaard, J.; Monteiro, M. J. P. F. G; Gizon, L.; Di Mauro, M. P.; Aerts, C.; Daszynska-Daszkiewicz, J.; Corbard, T. Bibcode: 2006ESASP.617E.157R Altcode: 2006soho...17E.157R No abstract at ADS Title: The Dynamics Project Authors: Turck-Chièze, S.; Schmutz, W.; Thuillier, G.; Jefferies, S.; Pallé; Dewitt, S.; Ballot, J.; Berthomieu, G.; Bonanno, A.; Brun, A. S.; Christensen-Dalsgaard, J.; Corbard, T.; Couvidat, S.; Darwich, A. M.; Dintrans, B.; Domingo, V.; Finsterle, W.; Fossat, E.; Garcia, R. A.; Gelly, B.; Gough, D.; Guzik, J.; Jiménez, A. J.; Jiménez-Reyes, S.; Kosovichev, A.; Lambert, P.; Lefebvre, S.; Lopes, I.; Martic, M.; Mathis, S.; Mathur, S.; Nghiem, P. A. P.; Piau, L.; Provost, J.; Rieutord, M.; Robillot, J. M.; Rogers, T.; Roudier, T.; Roxburgh, I.; Rozelot, J. P.; Straka, C.; Talon, S.; Théado, S.; Thompson, M.; Vauclair, S.; Zahn, J. P. Bibcode: 2006ESASP.617E.162T Altcode: 2006soho...17E.162T 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: Jovian seismology: preliminary results of the SYMPA instrument Authors: Gaulme, P.; Schmider, F. X.; Gay, J.; Jacob, C.; Jeanneaux, F.; Alvarez, M.; Reyes, M.; Valtier, J. C.; Fossat, E.; Palle, P. L.; Belmonte, J. C.; Gelly, B. Bibcode: 2006sf2a.conf..403G Altcode: Jupiter's internal structure is poorly known (Guillot et al. 2004). Seismology is a powerful tool to investigate the internal structure of planets and stars, by analyzing how acoustic waves propagate. Mosser (1997) and Gudkova & Zarkhov (1999) showed that the detection and the identification of non-radial modes up to degree ℓ=25 can constrain strongly the internal structure. SYMPA is a ground-based network project dedicated to the Jovian oscillations (Schmider et al. 2002). The instrument is composed of a Mach-Zehnder interferometer producing four interferograms of the planetary spectrum. The combination of the four images in phase quadrature allows the reconstruction of the incident light phase, which is related to the Doppler shift generated by the oscillations. Two SYMPA instruments were built at the Nice university and were used simultaneously during two observation campaigns, in 2004 and 2005, at the San Pedro Martir observatory (Mexico) and the Teide observatory (Las Canarias). We will present for the first time the data processing and the preliminary results of the experiment. Title: GOLF-NG spectrometer, a space prototype for studying the dynamics of the deep solar interior Authors: Turck-Chièze, Sylvaine; Carton, Pierre-Henri; Ballot, Jérome; Barrière, Jean-Christophe; Daniel-Thomas, Philippe; Delbart, Alain; Desforges, Daniel; Garcia, Rafaël A.; Granelli, Rémi; Mathur, Savita; Nunio, François; Piret, Yves; Pallé, Pere L.; Jiménez, Antonio J.; Jiménez-Reyes, Sebastian J.; Robillot, Jean Maurice; Fossat, Eric; Eff-Darwich, Antonio. M.; Gelly, Bernard Bibcode: 2006AdSpR..38.1812T Altcode: 2005astro.ph.10753T The GOLF-NG (Global Oscillations at Low Frequency New Generation) instrument is devoted to the search for solar gravity and acoustic modes, and also chromospheric modes from space. This instrument which is a successor to GOLF/SOHO will contribute to improve our knowledge of the dynamics of the solar radiative zone. It is a 15 points resonant scattering spectrometer, working on the D1 sodium line. A ground-based prototype is under construction to validate the difficult issues. It will be installed at the Teide Observatory, on Tenerife in 2006 to analyse the separation of the effects of the magnetic turbulence of the line from the solar oscillations. We are prepared to put a space version of this instrument including a capability of identification of the modes, in orbit during the next decade. This instrument should be included in the ILWS program as it offers a key to the improvement of our knowledge of the solar core in combination with observations from SDO and PICARD. We hope to determine the core rotation and magnetic field, through precise measurements of oscillation mode frequency splittings. Understanding the magnetic field of the radiative zone is important for progress in the study of solar activity sources, an important player for the long-term Sun-Earth relationship. Title: The origin of the solar cyclic activities: the DynaMICS project Authors: Turck-Chieze, S.; Brun, A. S.; Garcia, R. A.; Jiménez-Reyes, S. J.; Palle, P.; Dynamics Team Bibcode: 2006cosp...36.2001T Altcode: 2006cosp.meet.2001T In order to better estimate the earth climatic variations at scales corresponding to decennia or centuries it appears more and more important to understand the internal origin of the solar magnetic cyclic activities together with the evolution of the internal solar rotation profile It is the only way to be able to predict how they will evolve in the future The seismic techniques are totally adapted to this knowledge and an enriched information will allow to interpret the solar global variations as irradiance luminosity at different wavelengths and will measure temporal global mode characteristics which must be linked to the total magnetic fluxes ldots Our main objectives are to predict the characteristics of the coming solar cycles and to determine if there is different origins for the longer solar cycles or if it is only a temporal evolution of the eleven cycle 22 years which produces grand minima or maxima SDO is well adapted to progress on the convective zone with increased resolution in comparison with the SoHO mission it will allow to improve the 11 year solar cycle predictions In complementarity we consider very important to get a general description of the dynamics of the solar radiative zone which contains the main part of the solar mass and to understand the interconnection between magnetic fields of the radiative zone and of the convective zones Such information stays today poorly known even SoHO results on the solar radiative zone through acoustic and gravity modes are very promising to pursue this investigation In this Title: Jis - the Joint Information System Authors: Kienreich, I.; Hanslmeier, A.; Palle, P.; Sosa, A. Bibcode: 2005ESASP.600E.159K Altcode: 2005dysu.confE.159K; 2005ESPM...11..159K No abstract at ADS Title: GOLF New Generation: a spectrophotometer for the quest of solar gravity modes Authors: Turck-Chièze, S.; Mathur, S.; Carton, P. H.; García, R. A.; Palle, P.; Ballot, J. Bibcode: 2005sf2a.conf..167T Altcode: The Global Oscillations at Low Frequency: New Generation instrument (GOLF-NG), the successor of GOLF aboard SoHO, is devoted to the study the dynamics of the solar radiative zone thanks to the detection of solar gravity modes and low-frequency acoustic modes. This instrument built under a French-Spanish collaboration, is based on the Doppler velocity method using a 15 points resonant scattering spectrometer working on the D1 sodium line and will be placed in Tenerife. The observations of the space version called DynaMICS (for Dynamics and Magnetism of the Innner Core of the Sun) will enable us to improve our knowledge of the radiative zone, especially the solar core and the influence of the Sun on our planet by the determination of the origin of the magnetic activities. The investigation of the sodium line will also provide interesting information on the atmosphere of the Sun, between the photosphere and the chromosphere. Title: Global solar Doppler velocity determination with the GOLF/SoHO instrument Authors: García, R. A.; Turck-Chièze, S.; Boumier, P.; Robillot, J. M.; Bertello, L.; Charra, J.; Dzitko, H.; Gabriel, A. H.; Jiménez-Reyes, S. J.; Pallé, P. L.; Renaud, C.; Roca Cortés, T.; Ulrich, R. K. Bibcode: 2005A&A...442..385G Altcode: The Global Oscillation at Low Frequencies (GOLF) experiment is a resonant scattering spectrophotometer on board the Solar and Heliospheric Observatory (SoHO) mission, originally designed to measure the disk-integrated solar oscillations of the Sun. This instrument was designed in a relative photometric mode involving both wings of the neutral sodium doublet (D1 at λ 5896 and D2 at λ 5890 Å). However, a "one-wing" photometric mode has been selected to ensure 100% continuity in the measurements after a problem in the polarization mechanisms. Thus the velocity is obtained from only two points on the same wing of the lines. This operating configuration imposes tighter constraints on the stability of the instrument with a higher sensitivity to instrumental variations. In this paper we discuss the evolution of the instrument during the last 8 years in space and the corrections applied to the measured counting rates due to known instrumental effects. We also describe a scaling procedure to obtain the variation of the Doppler velocity based on our knowledge of the sodium profile slope and we compare it to previous velocity estimations. Title: JIS - the Joint Information System Authors: Hanslmeier, A.; Kienreich, I.; Palle, P.; Sosa, A. Bibcode: 2005HvaOB..29..329H Altcode: The main aim of JIS (Joint Information System) is to overcome the present lack of detailed knowledge amongst the European Solar Physics community. This lack of knowledge occurs at several levels: groups of researchers, institutions, scientific activities, running programs, resources, new opportunities, observational campaigns etc.

JIS will not be data archives -- this is the aim of EGSO, but will provide all information mentioned above collecting all possible data about the institutes and scientists working in the field of solar physics. All European solar physicists will be provided with this information by means of an easy accessible webpage including different inquiry modes (query by country, university, institute, scientist and area of research). Until now such a system did not exist in Europe, but in foreseeable future a user-friendly and logical structured webpage will take on this task. Title: The solar radiative interior: gravity modes and future instrumentation Authors: Garcia, R. A.; Turck-Chieze, S.; Ballot, J.; Couvidat, S.; Eff-Darwich, A.; Jiménez-Reyes, S. J.; Mathur, S.; Pallé, P. L.; GOLF-Ng Team Bibcode: 2004sf2a.conf...99G Altcode: 2004sf2a.confE.281G Today, the knowledge of the solar radiative interior is obtained by the solar acoustic modes. Thanks to the latest modes detected by SoHO the sound speed has been determined down to 0.06 Ro with a resolution of 3%. This profile is used to improve the solar model and its deviations from a static vision. The rotation profile is now clearly established down to the limit of the core (Garcia et al. 2004). In order to progress toward the core and reduce the uncertainties in the radiative region, gravity modes should be measured. Recently, Turck-Chieze et al. (2004) have identified some patterns using GOLF data during the last solar minimum, that can be interpreted in terms of gravity modes. These candidates, with an amplitude of ~2 mm/s, are at the limit of the signal-to-noise ratio and are difficult to follow when the activity increases. Their research will continue until the end of the SoHO lifetime in 2008 during the next solar minimum. In the best case, only a few mixed and gravity modes will be detected with SoHO. This is the reason why a French-Spanish collaboration is now building a prototype of a new spatial instrument, GOLF-NG, that will be tested during the Summer 2005 in the Observatorio del Teide. GOLF-NG will directly address the problem of the solar convective background noise to improve the g-mode detection. 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: Gravity Modes with a Resonant Scattering Spectrophotometer Authors: Turck-Chièze, S.; Garcia, R. A.; Couvidat, S.; Ballot, J.; Jiménez-Reyes, S. J.; Fossat, E.; Gelly, B.; Mathur, S.; Nghiem, P. A. P.; Pallé, P.; Robillot, Jm.; GOLF-Ng Technical Team Bibcode: 2004ESASP.559...85T Altcode: 2004soho...14...85T No abstract at ADS Title: Erratum: ``Looking for Gravity-Mode Multiplets with the GOLF Experiment aboard SOHO'' (ApJ, 604, 455 [2004]) Authors: Turck-Chièze, S.; García, R. A.; Couvidat, S.; Ulrich, R. K.; Bertello, L.; Varadi, F.; Kosovichev, A. G.; Gabriel, A. H.; Berthomieu, G.; Brun, A. S.; Lopes, I.; Pallé, P.; Provost, J.; Robillot, J. M.; Roca Cortés, T. Bibcode: 2004ApJ...608..610T Altcode: As a result of an error at the Press, the second panel of Figure 9 was repeated twice in the top row of the printed, black-and-white version of this figure, and the first panel was omitted. This error appears in the print edition and the PDF and postscript (PS) versions available with the electronic edition of the journal, although the panels of the color figure displayed in the electronic article itself are correct. Please see below for the corrected print version of Figure 9. The Press sincerely regrets the error. Title: About the rotation of the solar radiative interior Authors: García, R. A.; Corbard, T.; Chaplin, W. J.; Couvidat, S.; Eff-Darwich, A.; Jiménez-Reyes, S. J.; Korzennik, S. G.; Ballot, J.; Boumier, P.; Fossat, E.; Henney, C. J.; Howe, R.; Lazrek, M.; Lochard, J.; Pallé, P. L.; Turck-Chièze, S. Bibcode: 2004SoPh..220..269G Altcode: In the modern era of helioseismology we have a wealth of high-quality data available, e.g., more than 6 years of data collected by the various instruments on board the SOHO mission, and an even more extensive ground-based set of observations covering a full solar cycle. Thanks to this effort a detailed picture of the internal rotation of the Sun has been constructed. In this paper we present some of the actions that should be done to improve our knowledge of the inner rotation profile discussed during the workshop organized at Saclay on June 2003 on this topic. In particular we will concentrate on the extraction of the rotational frequency splittings of low- and medium-degree modes and their influence on the rotation of deeper layers. Furthermore, for the first time a full set of individual |m|-component rotational splittings is computed for modes ℓ≤4 and 1<ν<2 mHz, opening new studies on the latitudinal dependence of the rotation rate in the radiative interior. It will also be shown that these splittings have the footprints of the differential rotation of the convective zone which can be extremely useful to study the differential rotation of other stars where only these low-degree modes will be available. Title: Looking for Gravity-Mode Multiplets with the GOLF Experiment aboard SOHO Authors: Turck-Chièze, S.; García, R. A.; Couvidat, S.; Ulrich, R. K.; Bertello, L.; Varadi, F.; Kosovichev, A. G.; Gabriel, A. H.; Berthomieu, G.; Brun, A. S.; Lopes, I.; Pallé, P.; Provost, J.; Robillot, J. M.; Roca Cortés, T. Bibcode: 2004ApJ...604..455T Altcode: This paper is focused on the search for low-amplitude solar gravity modes between 150 and 400 μHz, corresponding to low-degree, low-order modes. It presents results based on an original strategy that looks for multiplets instead of single peaks, taking into consideration our knowledge of the solar interior from acoustic modes. Five years of quasi-continuous measurements collected with the helioseismic GOLF experiment aboard the SOHO spacecraft are analyzed. We use different power spectrum estimators and calculate confidence levels for the most significant peaks. This approach allows us to look for signals with velocities down to 2 mm s-1, not far from the limit of existing instruments aboard SOHO, amplitudes that have never been investigated up to now. We apply the method to series of 1290 days, beginning in 1996 April, near the solar cycle minimum. An automatic detection algorithm lists those peaks and multiplets that have a probability of more than 90% of not being pure noise. The detected patterns are then followed in time, considering also series of 1768 and 2034 days, partly covering the solar cycle maximum. In the analyzed frequency range, the probability of detection of the multiplets does not increase with time as for very long lifetime modes. This is partly due to the observational conditions after 1998 October and the degradation of these observational conditions near the solar maximum, since these modes have a ``mixed'' character and probably behave as acoustic modes. Several structures retain our attention because of the presence of persistent peaks along the whole time span. These features may support the idea of an increase of the rotation in the inner core. There are good arguments for thinking that complementary observations up to the solar activity minimum in 2007 will be decisive for drawing conclusions on the presence or absence of gravity modes detected aboard the SOHO satellite. Title: Solar gravity modes: the present and future Authors: Turck-Chièze, S.; Garcià, R.; Fossat, E.; Gelly, B.; Palle, P.; Robillot, Jm; Golf-Ng Bibcode: 2004cosp...35.3949T Altcode: 2004cosp.meet.3949T Gravity modes are the best probes to study the solar radiative zone, in particular the nuclear core and to follow its potential variability with time and latitude. Nevertheless, their amplitude is small and the solar noise particularly high in the range of frequency where they stand (below 500 μ Hz). It is why they are looked for more than 20 years and actively serached with GOLF and MDI instruments aboard SoHO which offers the best conditions of observation. Some candidates (Turck-Chièze et al. 2004) have been identified in the GOLF instrument, during the period of low solar activity thanks to an original research of multiplets corresponding to surface amplitudes of about 2mm/s. The examination of the interesting frequency range (100 to 400 μ Hz) will be pursued up to the end of the SoHO mission scheduled for 2007. Today our knowledge of the radiative zone is due to acoustic modes. Recent clear progress is due to the detection of modes less influenced by the sun activity, in the range 400-1600 μ Hz. The sound speed is determined down to 0.06 Ro with a resolution of 3%. This profile is used to improve the solar model and its deviations from a static vision. The rotation profile is now clearly established down to the limit of the core and its rigidity can only be explained by invoking a magnetic field effect. We present here GOLF-NG (Turck-Chièze et al., 2000) built by a French Spanish collaboration to improve g-mode detection. Based on the Doppler velocity method using a resonant spectrometer with a 16 channels on the sodium line, the main objective of GOLF-NG is to contribute to get an MHD picture of the Sun to better understand the influence of the Sun on earth climate, in improving the detection by a factor 10 in decreasing the solar noise thanks to a variable magnet. Consequently, the physical information will be extracted at different heights in the atmosphere. A prototype will be installed in 2005 in Tenerife. Then a spatial version will be available for taking place in one project of the ILWS mission. Turck-Chièze, S., Robillot, J.M., Dzitko, H ., Boumier, P., Decaudin, M., Gabriel, A.H., Garcia, R.A., Grec, G., Pallé, P.L., Renaud, C., Schmidt, D., 2000, ESA SP-464, 331; Turck-Chieze, S., Garcia, R.A., Couvidat, S., et al., 2004, ApJ, vol 604, Title: Helioseismology: probing the solar interior Authors: Palle, P. L. Bibcode: 2004cosp...35.4454P Altcode: 2004cosp.meet.4454P The direct access to the interior of the Sun has been possible, over the past 25 years, by successfully applying seismic techniques to detect and to characterize the whole spectrum of its oscillation eigenmodes. The unique and huge amount of observational data provided by earth-based networks and space-borne instruments, has allowed a high degree of refinement on present Solar Models as well as the development of robust inversion techniques. In addition, the sensitivity and correlation of acoustic solar eigenmodes characteristics (frequencies, power, linewidths, etc.) to solar activity (as measured by any of the many indicators) is providing further and additional insights on the so-called "Solar Activity Cycle". In this talk, a comprehensive review on the actual knowledge of the interior of the Sun and its relation with solar variability will be presented. Title: Solar gravity modes: the present and future Authors: Turck-Chièze, S.; Garcià, R.; Fossat, E.; Gelly, B.; Palle, P.; Robillot, Jm Bibcode: 2004cosp...35.3946T Altcode: 2004cosp.meet.3946T Gravity modes are the best probes to study the solar radiative zone, in particular the nuclear core and to follow its potential variability with time and latitude. Nevertheless, their amplitude is small and the solar noise particularly high in the range of frequency where they stand (below 500 μ Hz). It is why they are looked for more than 20 years and actively serached with GOLF and MDI instruments aboard SoHO which offers the best conditions of observation. Some candidates (Turck-Chièze et al. 2004) have been identified in the GOLF instrument, during the period of low solar activity thanks to an original research of multiplets corresponding to surface amplitudes of about 2mm/s. The examination of the interesting frequency range (100 to 400 μ Hz) will be pursued up to the end of the SoHO mission scheduled for 2007. Today our knowledge of the radiative zone is due to acoustic modes. Recent clear progress is due to the detection of modes less influenced by the sun activity, in the range 400-1600 μ Hz. The sound speed is determined down to 0.06 Ro with a resolution of 3%. This profile is used to improve the solar model and its deviations from a static vision. The rotation profile is now clearly established down to the limit of the core and its rigidity can only be explained by invoking a magnetic field effect. We present here GOLF-NG (Turck-Chièze et al., 2000) built by a French Spanish collaboration to improve g-mode detection. Based on the Doppler velocity method using a resonant spectrometer with a 16 channels on the sodium line, the main objective of GOLF-NG is to contribute to get an MHD picture of the Sun to better understand the influence of the Sun on earth climate, in improving the detection by a factor 10 in decreasing the solar noise thanks to a variable magnet. Consequently, the physical information will be extracted at different heights in the atmosphere. A prototype will be installed in 2005 in Tenerife. Then a spatial version will be available for taking place in one project of the ILWS mission. Turck-Chièze, S., Robillot, J.M., Dzitko, H ., Boumier, P., Decaudin, M., Gabriel, A.H., Garcia, R.A., Grec, G., Pallé, P.L., Renaud, C., Schmidt, D., 2000, ESA SP-464, 331; Turck-Chièze, S., Garcia, R.A., Couvidat, S., et al., 2004, ApJ, vol 604, Title: Eleven years of IRIS frequencies and splittings Authors: Fossat, E.; Salabert, David; Cacciani, A.; Ehgamberdiev, S.; Gelly, B.; Grec, G.; Hoeksema, J. T.; Kholikov, S.; Lazrek, M.; Palle, P.; Schmider, F. X.; Tomczyk, S. Bibcode: 2003ESASP.517..139F Altcode: 2003soho...12..139F Having acquired since July, 1989, a complete 11-year solar cycle of full disk data, the IRIS++ network has now made available to anyone the longest helioseismic data base to-date. A few results obtained from this very long time series are briefly presented here, with some emphasis on the low degree p-mode frequencies themselves, and their rotational splittings that have been estimated with unprecedented accuracy. 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: IRIS++ database: Merging of IRIS + Mark-1 + LOWL Authors: Salabert, D.; Fossat, E.; Gelly, B.; Tomczyk, S.; Pallé, P.; Jiménez-Reyes, S. J.; Cacciani, A.; Corbard, T.; Ehgamberdiev, S.; Grec, G.; Hoeksema, J. T.; Kholikov, S.; Lazrek, M.; Schmider, F. X. Bibcode: 2002A&A...390..717S Altcode: The IRIS network has been operated continuously since July 1st 1989. To date, it has acquired more than a complete solar cycle of full-disk helioseismic data which has been used to constrain the structure and rotation of the deep solar interior. However, the duty cycle of the network data has never reached initial expectations. To improve this situation, several cooperations have been developed with teams collecting observations with similar instruments. This paper demonstrates that we are able to merge data from these different instruments in a consistent manner resulting in a very significant improvement in network duty cycle over more than one solar cycle initiating what we call the IRIS++ network. The integrated radial velocities from the IRIS++ database (1989 to 1999) are 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/390/717 Title: Analysis of variability of p-mode parameters in 11 years of IRIS data Authors: Salabert, D.; Jiménez-Reyes, S. J.; Fossat, E.; Cacciani, A.; Ehgamberdiev, S.; Gelly, B.; Grec, G.; Hoeksema, J. T.; Khalikov, S.; Lazrek, M.; Pallé, P.; Schmider, F. X.; Tomczyk, S. Bibcode: 2002ESASP.477..253S Altcode: 2002scsw.conf..253S 11 years of IRIS (the low degree helioseismology network) have been analysed for the study of p-modes parameters variability. The duty cycle of the network data has been improved by the partial gap filling method named "repetitive music". This paper discusses the variations of all p-modes parameters along these 11 years. Title: δ Scuti stars with STARE: a project on planetary transits and stellar variability Authors: Alonso, R.; Brown, T. M.; Belmonte, J. A.; Charbonneau, D.; Fox Machado, L.; Pallé, P. L. Bibcode: 2002ESASP.485..245A Altcode: 2002sshp.conf..245A In this contribution, we show the capability of STARE to obtain frequencies and amplitudes from high temporal resolution δ Scuti spectra. Lightcurves of 13 new field δ Scuti stars are analyzed and a total of 21 oscillation modes are found in a single field. Noise level in the spectra falls bellow 3 mmag for stars fainter than magnitude 9. Subsequent analysis of the other observed fields, a new location for STARE, as well as the sharing of data with similar projects will provide higher-quality results and a valuable δ Scuti database, which would be useful for follow-up observations. Title: The STELLA project: two 1.2m robotic telescopes for simultaneous high-resolution Echelle spectroscopy and imaging photometry Authors: Strassmeier, K. G.; Granzer, T.; Weber, M.; Woche, M.; Hildebrandt, G.; Bauer, S. -M.; Paschke, J.; Roth, M. M.; Washuettl, A.; Arlt, K.; Stolz, P. A.; Schmitt, J. H. M. M.; Hempelmann, A.; Hagen, H. -J.; Ruder, H.; Palle, P. L.; Arnay, R. Bibcode: 2001AN....322..287S Altcode: We present an overview and a brief report on the status of the STELLA project (abbreviation for STELLar Activity). The STELLA-I telescope will be the first robotic telescope that feeds a bench-mounted high-resolution Echelle spectrograph with a set of 50 and 100 μm fibres and provides spectral resolutions of up to 47,000 with a 1 arcsec slit. The spectrograph is a white-pupil design located in a separated temperature-controlled room to guarantee long-term stability. The building will have a roll-off roof and is capable to host two telescopes. First light for STELLA-I is planned for summer 2002. STELLA-II is foreseen to be a photometric imaging telescope for the optical and near-infrared wavelengths and will follow in 2003. Title: Analysis of the solar cycle and core rotation using 15 years of Mark-I observations: 1984-1999 . I. The solar cycle Authors: Jiménez-Reyes, S. J.; Corbard, T.; Pallé, P. L.; Roca Cortés, T.; Tomczyk, S. Bibcode: 2001A&A...379..622J Altcode: 2001astro.ph.10364J High quality observations of the low-degree acoustic modes (p-modes) exist for almost two complete solar cycles using the solar spectrophotometer Mark-I, located at the Observatorio del Teide (Tenerife, Spain) and operating now as part of the Birmingham Solar Oscillations Network (BiSON). We have performed a Fourier analysis of 30 calibrated time-series of one year duration covering a total period of 15 years between 1984 and 1999. Applying different techniques to the resulting power spectra, we study the signature of the solar activity changes on the low-degree p-modes. We show that the variation of the central frequencies and the total velocity power (TVP) changes. A new method of simultaneous fit is developed and a special effort has been made to study the frequency-dependence of the frequency shift. The results confirm a variation of the central frequencies of acoustic modes of about 0.45 mu Hz, peak-to-peak, on average for low degree modes between 2.5 and 3.7 mHz. The TVP is anti-correlated with the common activity indices with a decrease of about 20% between the minimum and the maximum of solar cycle 22. The results are compared with those obtained for intermediate degrees, using the LOWL data. The frequency shift is found to increase with the degree with a weak l-dependence similar to that of the inverse mode mass. This verifies earlier suggestions that near surface effects are predominant. Title: An estimation of global solar p-mode frequencies from IRIS network data: 1989-1996 Authors: Serebryanskiy, A.; Ehgamberdiev, Sh.; Kholikov, Sh.; Fossat, E.; Gelly, B.; Schmider, F. X.; Grec, G.; Cacciani, A.; Palle, P. L.; Lazrek, M.; Hoeksema, J. T. Bibcode: 2001NewA....6..189S Altcode: The IRIS network has accumulated full disk helioseismological data since July 1989, i.e. a complete 11-year solar cycle. Since the last paper publishing a frequency list [A&A 317 (1997) L71], not only has the network acquired new data, but has also developed new co-operative programs with compatible instruments [Abstr. SOHO 6/GONG 98 Workshop (1998) 51], so that merging IRIS files with these co-operative program data sets has made possible the improvement of the overall duty cycle. This paper presents new estimations of low degree p-mode frequencies obtained from this IRIS++ data bank covering the period 1989-1996, as well as the variation of their main parameters along the total range of magnetic activity, from before the last maximum to the very minimum. A preliminary estimation of the peak profile asymmetries is also included. Title: Foreword Authors: Pallé, Pere L. Bibcode: 2001ESASP.464....3P Altcode: 2001soho...10....3P No abstract at ADS Title: g-mode: a new generation of helioseismic instrument Authors: Turck-Chièze, S.; Robillot, J. M.; Dzitko, H.; Boumier, P.; Decaudin, M.; Gabriel, A.; Garcia, R. A.; Gree, G.; Pallé, P. L.; Renaud, C.; Schmitt, D. Bibcode: 2001ESASP.464..331T Altcode: 2001soho...10..331T The GOLF team pushes a new concept of instrument devoted to the search of gravity modes and low order low frequency p modes in order to improve our knowledge of the deep solar interior. The instrumental concept is to measure the Doppler shift together with the time evolution of the D1 sodium line using a 15 point resonance spectrometer. A sodium vapor resonance cell placed in a static magnetic field varying along the longitudinal axis is used to sample simultaneously 8 points on each wing of the line. New Active Pixel Sensor detectors will be specifically designed for this instrument. A low spatial resolution of the Sun is also under study in this concept. First ground-based observations with this instrument are scheduled for 2001/2002 at Tenerife. The space concept of this instrument is under study in France as an R&T (Research and Technology) study sponsored by CNES, the French Space Agency. After some determining validation tests, this kind of instrument might be placed onboard either a micro satellite or a satellite dedicated to the study of the Sun. Title: LOWL p-mode frequencies and their variation with solar activity Authors: Jiménez-Reyes, Sebastián J.; Corbard, Thierry; Pallé, Pere L.; Tomczyk, Steve Bibcode: 2001ESASP.464..107J Altcode: 2001soho...10..107J; 2000astro.ph.11410J We present an analysis of the frequency shift and the even terms of the frequency splitting coefficients carried out using six years of LOWL data, starting in 1994. The temporal Variations and their Dependences with the frequency and degree are addressed. The results are consistent with previous analysis. Title: Helio- and asteroseismology at the dawn of the millennium Authors: Wilson, A.; Pallé, Pere L. Bibcode: 2001ESASP.464.....W Altcode: 2001soho...10.....W No abstract at ADS Title: Signature of the solar cycle in the low degree p-modes using Mark-I Authors: Jiménez-Reyes, Sebastián J.; Corbard, Thierry; Pallé, Pere L. Bibcode: 2001ESASP.464..103J Altcode: 2001soho...10..103J; 2000astro.ph.11411J High quality observations of the low degree p-modes exist for almost two complete solar cycles using the solar spectrophotometer Mark-I, located and operating at the Observatorio del Teide (Tenerife, Spain). In this work, the observations available have been re-analyzed over a much wider time interval than before. We analyze the time variation of the yearly frequency shift and its frequency dependence. This information will be used in order to average annual power spectra by removing the effect of the solar cycle. Using this average power spectrum, a new estimate of the rotational splittings is attempted. Title: A self-consistent procedure to detect low-l low-n solar p-modes Authors: Eff-Darwich, A.; Régulo, C.; Roca Cortés, T.; Pallé, P. L.; Korzennik, S. G. Bibcode: 2001ESASP.464..511E Altcode: 2001soho...10..511E Recent data colleted by the helioseismic experiments aboard SOHO have allowed the detection of low degree p-modes with lower and lower order, n. In particular, the GOLF experiment is currently able to identify unambiguously modes as low as n = 8 for l = 0, and l = 1 (e.g., ≍1.3 mHz). To detect p-modes with lower n (hence lower frequeny), where the signal-to-noise ratio gets small, one needs some guidance. Several groups use theoretical predictions from a standard solar model as a guide. But using theoretical predictions has the potential to bias the mode identification and in turn produce modes that confirm the features of the model rather than the properties of the actual sun. To alleviate this, we propose an alternative methodology based on peak fitting techniques and helioseismic data inversion procedures. This method allow us to reject many peaks from the spectrum by using the prediction capability of the inversion. We describe the method and show resuls from its application to current GOLF spectra. Title: Solar cycle variations of oscillation mode parameters from LOWL and MARK-I instruments Authors: Jimeńez Reyes, S. J.; Corbard, T.; Tomczyk, S.; Pallé, P. L. Bibcode: 2000SPD....31.0112J Altcode: 2000BAAS...32.1289J The signature of the Solar-Cycle appears clearly in the p-mode parameters (Jiménez-Reyes et al. 1998, Libbrecht & Woodard 1990, and Anguera et al. 1992). At present, the study of the p-mode parameter variation is a very active topic in helioseismology where, thanks to projects like BISON, IRIS, GONG, LOWL and MDI, we are able for the first time to analyse, using heliosismology, how the Sun internal structure and dynamic change over the magnetic cycle. High-quality observations for low degree p-modes have been accumulated for more than twenty years using the solar spectro photometer MARK-I, located and operating at the Observatorio del Teide (Tenerife, Spain). The data-base available have been re-analyzed over a much wider time interval than before. Moreover, the LOWL instrument, a Potassium Magneto-Optical Filter, located at the Manua Loa Observatory, has been measuring for more than six years solar oscillations of intermadiate p-mode degree. The data-base represents one of the best available to analyze the influence of the Solar-Cycle on the mode parameters, mainly because these data, concerning both low and intermadiate degree modes, give us information over an extensive range of the solar depths which may allow us to locate characteristics of the solar dynamo process. Using different data sets and different techniques, we analyse the behaviour of the solar p-modes in an attempt to better understand the origin of the Solar-Cycle. Title: The ECHO (Experiment for Coordinated Helioseismic Observations) Network Authors: Tomczyk, S.; Jiménez Reyes, S. J.; Jiménez, A.; Pallé, P. L. Bibcode: 2000SPD....31.0117T Altcode: 2000BAAS...32..804T The High Altitude Observatory of the National Center for Atmospheric Research (HAO/NCAR) in collaboration with the Instituto de Astrofísica de Canarias (IAC) have recently completed a two-station helioseismic network with sites at Mauna Loa, Hawaii and Izana, Tenerife. The instruments are Doppler imagers employing Magneto-Optical filters and are based on the existing LOWL instrument. We expect the network to provide a duty cycle of 50%, compared to 22% for the LOWL. In addition, the ECHO incorporates several improvements over the LOWL including: 1) a CCD detector with square pixels and a factor of two increase in spatial resolution; 2) better guiding; 3) exchange of red and blue images every 15 seconds to better facilitate detector flat fielding; and 4) improved thermal control of the instrument enclosure. We will present initial data from the network and demonstrate network performance. Title: p-mode Frequency Shift as Solar Activity Index Authors: Jiménez-Reyes, S. J.; Corbard, Thierry; Palle, Pere L.; Tomczyk Bibcode: 2000ESASP.463..341J Altcode: 2000sctc.proc..341J No abstract at ADS Title: Frequencies of Solar p-Modes from GOLF and VIRGO-SPM (SOHO) Authors: Roca Cortés, T.; Jiménez, A.; Pallé, P. L.; GOLF Team; Virgo Team Bibcode: 1999ESASP.448..135R Altcode: 1999ESPM....9..135R; 1999mfsp.conf..135R No abstract at ADS Title: A new observational strategy in search for solar g-modes Authors: Mateos, I. Martí; n.; Pallé, P. L. Bibcode: 1999SoPh..189..241M Altcode: The aim of the present work is the detection of solar g-modes, by means of a new observational strategy based on the exploitation of their spatial and temporal properties. The basic data, obtained at the Observatorio del Teide in 1993, consists of daily solar velocity measurements taken continuously and sequentially at six different and symmetric positions on the solar disk. By correlating the time series resulting from the reduction process, from different solar disk positions and considering the geometrical properties of different modes (l,m) on the Sun's surface, some of these can be selectively eliminated or enhanced. Moreover, the main spectral features present in the resulting power spectra must have precise phase relations if they correspond to global solar g-modes. The severe constraints established by the above properties have been applied to the best observed series (summer 1993). As a result, a discrete series of peaks have been selected that fulfill all the imposed conditions and which can therefore be interpreted as being of solar origin. Title: Power spectra comparison between GOLF and MDI velocity observations Authors: Henney, C. J.; Ulrich, R. K.; Bertello, L.; Bogart, R. S.; Bush, R. I.; Scherrer, P. H.; Palle, P. L.; Roca Cortes, T.; Turck-Chieze, S. Bibcode: 1999AAS...194.5617H Altcode: 1999BAAS...31..914H We present a comparison of the velocity power spectra between the GOLF and MDI instruments. In addition, this poster outlines work towards creating a GOLF-simulated signal utilizing MDI velocity images. The simulation of the GOLF signal is achieved by integrating spatially weighted masks with MDI LOI-proxy velocity images. The GOLF-simulated signal and a selection of additional spatially masked MDI velocity signals are compared with the observed GOLF signal for a 759 day period from May 25, 1996 through June 22, 1998. Ultimately, a cross-analysis process between GOLF and MDI signals could lead to an enhancement of our ability to detect low frequency solar oscillations. The signal-to-background ratio (S/B) for the GOLF and the spatially masked MDI velocity data is presented for low degree (l <= 3) and low frequency p-modes. We find that signals from both MDI and GOLF are beneficial for detecting low degree (l <= 3) and low frequency (< 2000 mu Hz) p-modes. For the frequency range and the signals compared in this poster, the GOLF signal has the highest S/B for l=0 p-modes. The S/B of the GOLF and MDI central region masked signals is good for detecting l=1 p-modes. For l >= 2 p-modes, the central region masked signals have the highest S/B of the power spectra compared here. In addition, the S/B of the preliminary GOLF-simulated signal is found to be more similar to the GOLF signal than the MDI LOI-proxy signal without spatial masking for the modes investigated here. Title: Improving the signal-to-noise ratio in solar oscillation spectra Authors: García, R. A.; Jefferies, S. M.; Toner, C. G.; Pallé, P. L. Bibcode: 1999A&A...346L..61G Altcode: We describe a data analysis technique for helioseismology that provides a reduction in the contamination of the solar oscillation spectrum from incoherent noise. We show that the technique allows: (i) a significant improvement in the signal-to-noise ratio for the modes in the oscillation power spectrum, and (ii) the solar velocity background spectrum to be observed at low frequencies using ground-based observations. Title: Full disk helioseismology: repetitive music and the question of gap filling Authors: Fossat, E.; Kholikov, Sh.; Gelly, B.; Schmider, F. X.; Fierry-Fraillon, D.; Grec, G.; Palle, P.; Cacciani, A.; Ehgamberdiev, S.; Hoeksema, J. T.; Lazrek, M. Bibcode: 1999A&A...343..608F Altcode: Helioseismology requires continuous measurements of very long duration, months to years. This paper addresses the specific and limited case of full disk measurements of p-mode oscillations, although it can be generalized, to some extent, to the case of imaged helioseismology. First, a method of mode by mode (or rather pair of modes by pair of modes) interpolation of the signal in gaps is tested, and shown to be efficient for gaps as long as two days, but limited to the frequency range where the signal to noise ratio is good. It is then noted that the autocorrelation function of the full disk signal, after dropping quickly to zero in 20 or 30 minutes, shows secondary quasi periodic bumps, due to the quasi-periodicity of the peak distribution in the Fourier spectrum. The first of these bumps, at 4 hours or so, is higher than 70 percent and climbs to nearly 90 percent in limited frequency ranges. This suggests that an easy gap filling method can be developed, with a confidence of nearly 90 percent across all the frequency range, as long as the gap does not exceed 8 hours, with at least 4 hours of data at both ends. Even a short gap of one or two periods is better filled by the data taken 4 hours earlier or later than by local interpolation. This relaxes quite considerably the requirement of continuity of the observations for the case the full disk p-mode helioseismology. Applied to 7 years of IRIS data, this method permits the detection of all low frequency p-modes already seen by 2 years of the GOLF instrument data, and makes possible the measurement of their frequencies with an accuracy consistent with the partially filled 7 years of statistics. Title: Results from the GOLF instrument on SOHO Authors: Gabriel, A. H.; Turck-Chièze, S.; García, R. A.; Pallé, P. L.; Boumier, P.; Thiery, S.; Baudin, F.; Grec, G.; Ulrich, R. K.; Bertello, L.; Roca Cortés, T.; Robillot, J. -M. Bibcode: 1999AdSpR..24..147G Altcode: An 800 day series of GOLF velocity data, with uniquely high continuity and stability, offers the best ever signal to noise ratio obtained in global Sun observations. Following meticulous efforts to provide reliable calibration, these data have been used for measurements of frequencies, line-widths and power in the p-modes, which are used for inversion to give the internal sound speed, for comparison with theoretical models. A search for g-modes is at present inconclusive, but has yielded two possible candidate frequencies. The analysis available today is regarded as preliminary and more complete methods are currently in hand. With the resumption of routine observations following the SOHO recovery, it is hoped that the data can be considerably extended, enabling changes with the solar cycle to be explored, as well as an extended g-mode search. Title: On the nature of the current GOLF p-mode signal Authors: Pallé, P. L.; Régulo, C.; Roca Cortés, T.; García, R. A.; Jiménez, A.; Boumier, P.; Gabriel, A.; Grec, G.; Robillot, J. M.; Turck-Chièze, S.; Ulrich, R. K.; SOI Team Bibcode: 1999A&A...341..625P Altcode: The GOLF experiment on board SOHO is designed to measure global oscillations of the disk-integrated sunlight with high sensitivity and with long term stability. The GOLF data is thus ideally suited for both the study of the p-mode spectrum and to address the search for gravity modes. Due to their occasional malfunction the project decided to stop the rotating polarizing elements at an optimum place in order to maintain a precise sequence of measurements with the highest possible duty cycle. This action means that subsequently GOLF only measures two monochromatic intensities {I}_b(+) and {I}_b(-) on the blue wing of the sodium doublet. In this work we investigate the nature of these signals separately and in combinations. Our method is to study the temporal relative phase relations between the low degree (l <= 3) p-mode signals derived from data sets obtained from simultaneous observations, both from other SOHO instruments (GOLF and SOI) and from Mark- I, the Tenerife station of the ground-based BiSON network. It is found that these signals are ``almost'' pure velocity signals. A simple model indicates that a contamination of a pure intensity-like signal of 14% amplitude would fully explain the true nature of the current GOLF signal. Moreover, it is found that the ratios, defined for other instruments (Mark-I, SOI and, by extension BiSON and IRIS), also have exactly the same nature as the GOLF ratio. Title: The Sun as a Star: Background, Intensity and Velocity, Power Spectra and Convection Authors: Pallé, P. L.; Roca Cortés, T.; Jiménez, A.; GOLF Team; Virgo Team Bibcode: 1999ASPC..173..297P Altcode: 1999sstt.conf..297P No abstract at ADS Title: Low L Solar p-Mode Oscillations Parameters and Convection Authors: Roca Cortés, T.; Montañés, P.; Pallé, P. L.; Pérez Hernández, F.; Jiménez, A.; Régulo, C.; GOLF Team Bibcode: 1999ASPC..173..305R Altcode: 1999sstt.conf..305R No abstract at ADS Title: Power spectra comparison between GOLF and MDI velocity observations. Authors: Henney, C. J.; Ulrich, R. K.; Bertello, L.; Bogart, R. S.; Bush, R. I.; Scherrer, P. H.; Pallé, P. L.; Roca Cortés, T.; Turck-Chièze, S. Bibcode: 1999BAAS...31Q1237H Altcode: No abstract at ADS Title: Measurements of the solar aureole at the Teide Observatory Authors: González Jorge, H.; Martínez Pillet, V.; Vázquez, M.; Pallé, P.; McGovern, F.; Raes, F. Bibcode: 1998NewAR..42..515G Altcode: Daily measurements of the solar aureole were made at the Vacuum Newton Telescope ( D=40 cm) at the Teide Observatory (Tenerife) for various airmasses. We use these measurements to understand how the aureole is produced and to extrapolate visible measurements to the infrared range (1.6 μm). This information will be used to correct sunspot photometric measurements. This programme is included in the second Aerosol Characterization Experiment (ACE-2) held on Tenerife from mid June to July 1997. During this period a large variety of aerosol measurements were made at different altitudes on the island and by aircraft flying over this area of the North Atlantic Ocean. This information will be used to constrain the physical parameters of the aerosols needed for our extrapolation. Title: High-Frequency Peaks in the Power Spectrum of Solar Velocity Observations from the GOLF Experiment Authors: García, R. A.; Pallé, P. L.; Turck-Chièze, S.; Osaki, Y.; Shibahashi, H.; Jefferies, S. M.; Boumier, P.; Gabriel, A. H.; Grec, G.; Robillot, J. M.; Roca Cortés, T.; Ulrich, R. K. Bibcode: 1998ApJ...504L..51G Altcode: The power spectrum of more than 630 days of full-disk solar velocity data, provided by the GOLF spectrophotometer aboard the Solar and Heliospheric Observatory, has revealed the presence of modelike structure well beyond the acoustic cutoff frequency for the solar atmosphere (νac~5.4 mHz). Similar data produced by full-disk instruments deployed in Earth-based networks (BiSON and IRIS) had not shown any peak structure above νac: this is probably due to the higher levels of noise that are inherent in Earth-based experiments. We show that the observed peak structure (νac<=ν<=7.5 mHz) can be explained by a simple two-wave interference model if the high-frequency waves are partially reflected at the back side of the Sun. Title: Probing the Solar Subphotospheric Layers Using Ring Analysis Authors: González Hernández, I.; Patrón, J.; Roca-Cortés, T.; Pérez Hernández, F.; Jiménez, A.; Jiménez-Reyes, S. J.; Martín, I.; Pallé, P. L.; Régulo, C. Bibcode: 1998Ap&SS.263..335G Altcode: 1999Ap&SS.263..335G; 1998Ap&SS.263..335H No abstract at ADS Title: 3-D Helioseismology: Rings and Horizontal Flows Authors: Patrón, J.; González Hernández, I.; Jiménez, A.; Jiménez-Reyes, S. J.; Martín, I.; Pallé, P. L.; Pérez Hernández, F.; Régulo, C.; Roca-Cortés, T. Bibcode: 1998Ap&SS.263..327P Altcode: 1999Ap&SS.263..327P No abstract at ADS Title: A New Observational Strategy to Search for Solar g-Modes Authors: Martín Mateos, I.; González Hernández, I.; Jiménez, A.; Jiménez-Reyes, S. J.; Patrón, J.; Pallé, P. L.; Pérez Hernández, F.; Régulo, C.; Roca-Cortés, T. Bibcode: 1998Ap&SS.263..339M Altcode: 1999Ap&SS.263..339M No abstract at ADS Title: The Solar Rotation Rate Ω(R, θ) Authors: Eff-Darwich, A.; Korzennik, S. G.; Roca Cortés, T.; Pérez Hernández, F.; Pallé, P. Bibcode: 1998Ap&SS.263..347E Altcode: 1999Ap&SS.263..347E In recent years, the capability to detect and analyse solar oscillation acoustic modes has greatly improved. The development of ground based networks like GONG or BiSON and the use of space platforms like SOHO has allowed us to study the structure and dynamics of the Sun with unprecedented precision. Title: Progress Toward an IRIS++ Database Open to the Helioseismological Community Authors: Gelly, B.; Khalikov, S.; Pallé, P. L.; IRIS Team Bibcode: 1998ESASP.418..199G Altcode: 1998soho....6..199G The IRIS network is now fourteen years old, and has continuously been taking data since 1989. The data analysis, which produced some noticeable scientifical results, like the measurement of the ell = 1 rotationnal splitting or the measurement of the solar acoustic cut-off frequency, was mainly performed with the summer campaigns data of 1989 to 1992. P-mode frequency and width tables were recently published using the same subset of the IRIS data . We are now finishing the calibration and the timing of the whole set of IRIS data from 89 to 97, which will increase by a factor of 4 the amount of available data. The duty cycle of the IRIS network ranges from about 65% over 3 months of the summer campaigns to some 23% over one year in the worst case. To improve our duty cycle we developed several collaborations with other teams running similar instruments: (1) the Mark I instrument, ran at the IAC for many years, a potassium resonance single pixel device, also part of the BiSON network (Elsworth et al., 1988). (2) Alexandro Cacciani's MOF, ran at the JPL in Pasadena. Although this is a sodium resonance imaging instrument, it has been used in ``one pixel'' format for several summer seasons since 1989 (Cacciani et al., 1984). (3) the LOWL instrument is a Doppler imager also based on a Magneto-Optical Filter (MOF), operated at the Mauna Loa solar observatory since 1994 (Tomczyk et al., 1995). The merging of those 'alien' data has been carefully adressed at the calibration ands timing stages, and we can now present the advantages of such a-posteriori collaborations. We endeavour to set-up the corresponding database of 'one-pixel seismological data from ground-based intruments' in Nice and to open it to the scientific community of this meeting by the end of 1998. This database will soon have the potential to trace the spectral features of the solar signal over one 11-years cycle. Title: Solar activity cycle frequency shifts of low-degree p-modes Authors: Jimenez-Reyes, S. J.; Regulo, C.; Palle, P. L.; Roca Cortes, T. Bibcode: 1998A&A...329.1119J Altcode: We report on an extensive analysis of the low-degree p-mode frequency shifts over Solar Cycle n(b {o}) 22 (1984--1995) based on continuous data taken at the Observatorio del Teide (Tenerife). Aside from the known good correlation between frequency shifts and solar activity indices, we have also investigated on short and long time-scales correlations (from 2 months to 1.5 years and from 1.5 to 11 years) showing different behavior. In addition, by using smoothed data for both, frequency shifts and solar activity indices, a ``hysteresis'' phenomenon is observed. This implies different behavior of both quantities in the ascending and descending parts of the cycle, while saturation effects exists at extreme phases. Finally, a degree dependence of this behavior is also noticed when analyzing separately the shifts for the even (0, 2) and odd (1, 3) mode groups. These results show that the p-mode frequency shifts are very sensitive to structural changes taking place in the Sun as the solar activity cycle proceeds; either in their upper layers, as activity migrates towards the equator, or, in its interior with a phenomenon that slowly progresses outwards, or both. A much more complete picture should emerge when data obtained from the new operational helioseismic projects over more than one solar cycle come into existence. Title: Frequency Stability in GOLF Data, 1996-97 Authors: Fierry Fraillon, D.; Pallé, P. L.; Golf Team Bibcode: 1998ESASP.418..911F Altcode: 1998soho....6..911F The solar activity, following an eleven years cycle, modifies the physical properties of the resonant cavity where the oscillation acoustic modes are trapped. Its effect on p-modes frequencies is a positive shift as the solar activity grows from a minimum to a maximum (Fossat et al. 1987, Pallé et al. 1989, Elsworth et al. 1990). A continuous set of observation like the Golf data set, fron the 11 April 1996 to the 3 January 1998, allows a study of the p-modes frequency shift during a minimal solar activity. We selected 3 power spectra with differents MPSI magnetic index and with a 36 days duration of observation according to the evolution time of the magnetic index. Then, we used a mode to mode cross-correlation technique in order to estimate an individual shift of the mean frequency of n = 13 to 24, l = 0 to 3 modes by fitting a Lorentzian profile on the cross-correlation. We also investigate for a global frequency shift using the same cross-correlation technique. The results show the evidence of the frequency stability of p-modes in the 19-months GOLF data set even with the light increase of the solar activity since September 1998. Title: High Frequency signal in GOLF Data Authors: Garcia, R. A.; Palle, P. L.; GOLF Team Bibcode: 1998IAUS..185..447G Altcode: No abstract at ADS Title: Solar Cycle Changes of the p-Mode Spectrum and Mean Irradiance Authors: Jiménez-Reyes, Sebastián J.; Pallé, Pere L. Bibcode: 1998sers.conf..419J Altcode: No abstract at ADS Title: On the Presence of the Solar 160-min Signal in GOLF Data Authors: Pallé, P. L.; Roca Cortés, T.; Gelly, B.; GOLF Team Bibcode: 1998ESASP.418..291P Altcode: 1998soho....6..291P GOLF data continuously obtained over the last two years, provides a unique and ideal set for studying the low frequency (ν <= 500 muHz) range of the solar spectrum oscillations. In this work we have focused our attention to the spectral region around 160 minute (~104.2 muHz), where a controversial ``solar g-mode'' is claimed to be (Kotov et al., 1997). Various spectral techniques have been used in order to reveal its possible presence and stability as well as to set an upper limit to its amplitude. In this poster, the results obtained at the time of the meeting will be presented and discussed. Title: On the Nature of the Current GOLF Signal Authors: Pallé, P. L.; Regulo, C.; Roca Cortés, T.; Garcia, R. A.; Jiménez, A.; GOLF Team Bibcode: 1998ESASP.418..285P Altcode: 1998soho....6..285P Although the occasional malfunction of rotating polarizing elements at the beginning of the SOHO mission, which led to its stop, GOLF instrument has been performing precise and continuous measurements over the last two years. In this work, the nature of the actual GOLF measurement, two monochromatic intensities Ib+ and Ib- on the blue wing of the sodium doublet, is investigated by comparing the temporal phase of the low degree (ell <= 3) p-modes obtained from simultaneous data sets, either from SOHO (GOLF in different operating modes) and from a well known ground-based instrument (MARK-I). It is found that the signals are ``almost'' pure velocity signals whose behaviour can be explained, amongst other possible mechanisms, by a contamination of an intensity-like signal of 14% amplitude. Furthermore is it proved that the ratio (instrumental velocity) as defined in MARK-I instrument (and by extension in IRIS one) do have the same nature as the GOLF blue wing signal Xb. Title: High-Frequency Signals in the Power Spectrum of Integrated Solar Velocity Observations from the GOLF Experiment Authors: Garcia, R. A.; Pallé, P. L.; Turck-Chièze, S.; Osaki, Y.; Shibahashi, H.; Jefferies, S.; GOLF Team Bibcode: 1998ESASP.418..177G Altcode: 1998soho....6..177G The power spectrum of ~630 days of full-disk solar velocity data, provided by the GOLF spectrophotometer aboard SOHO, has revealed the presence of mode-like structure well beyond the acoustic cut-off frequency for the solar atmosphere (nuac ~5.4 mHz). This kind of structure has already been observed in intermediate and high spatial resolution oscillation data (Duvall et al. 1991), but never before in integrated data like BiSON or IRIS. This is probably due to the higher level of noise that are inherent to the earth-based experiments. In this contribution, we analyse the observed peak structure (nuac < ν < 7.5 mHz) and we describe the theoretical analysis of such signal. Title: A Parametric Model of the Solar Full-Disk Seismological Signal Authors: Mouret, D.; Gelly, B.; Ferrari, A.; Pallé, P. L.; GOLF Team Bibcode: 1998ESASP.418..271M Altcode: 1998soho....6..271M Solar eigenmodes frequencies are most often determined using some kind of modelisation of the Fourier spectrum of the data in one or two dimensions. Many statistical refinements have lead to significant improvements in the determination of the frequencies and widths of the spectral lines. Nevertheless, this technique relies strongly on several asumptions on the nature of the signal (damped oscillators) and of the resulting spectrum (Lorentz profiles). We present here a different method based on the parametric modeling of the solar signal, seen as an autoregressive (AR) process of 2nd order. A parametric modeling with model orders between 20 to 35 is performed on the filtered GOLF signal, on a per-mode basis. Preliminary tests show that for ell = 0 modes the frequencies and widths from the parametric model are in good agreement (within the error-bars) of the 'classical' published results. A more complete evaluation is now ongoing and we will be presenting a first evaluation of the potential of this new signal analysis. Title: The Exact Fractions Technique Applied to the Search of Solar Gravity Modes Authors: Pallé, P. L.; Roca Cortés, T.; Gelly, B.; Pérez-Hernández, F.; GOLF Team Bibcode: 1998ESASP.418..279P Altcode: 1998soho....6..279P Amongst the different techniques applied up to now to the search for solar g--modes (peaks identification, study of the phase/power coherence, the P0 - nur diagrams, etc ldots), some ones are primarily based on the use of their asymptotic behaviour: the constant separation in period between consecutive modes of the same degree ell. The exact fractions technique is one of those and has already been applied to ground based helioseismology data (H.B. van der Raay, 1998). In the present work, the technique is fully tested in order to see of its adequacy when the asymptotic property is not fully accomplished, either because of the rotational splitting of the modes or because of the range of radial order values considered. The encouraging results obtained, led us to apply it to a temporal series of 690 consecutive days obtained with GOLF instrument on board SOHO. The results are shown by Gabriel et al. in this Workshop. Title: Application of a new observational strategy to the study of gravitational solar modes Authors: Martin Mateos, I.; Palle, P. L. Bibcode: 1998IAUS..185...51M Altcode: The aim of the present work is the detection of solar g-modes, making use of their spatial and temporal properties, by means of a new observational strategy. The basic data, gathered at the Observatorio del Teide in 1993, consists on daily solar velocity measurements taken continuous and sequentially at six different and symmetric positions on the solar disk. By correlating the time series resulting of the reduction process, from different positions and considering the geometrical properties of different modes (l,m) on the Sun's surface, some of them can selectively be eliminated of enhanced. Moreover the main spectral features present in the resulting power spectra must have precise phase relations if they correspond to global solar g-modes. The severe constraints that the above properties established, have been applied to the best observational obtained series (summer 1993). As a result, a discrete series of peaks have been selected that fulfill all the imposed conditions, and therefore they can be interpreted as being of solar origin. Title: First Results on it P Modes from GOLF Experiment Authors: Lazrek, M.; Baudin, F.; Bertello, L.; Boumier, P.; Charra, J.; Fierry-Fraillon, D.; Fossat, E.; Gabriel, A. H.; García, R. A.; Gelly, B.; Gouiffes, C.; Grec, G.; Pallé, P. L.; Pérez Hernández, F.; Régulo, C.; Renaud, C.; Robillot, J. -M.; Roca Cortés, T.; Turck-Chièze, S.; Ulrich, R. K. Bibcode: 1997SoPh..175..227L Altcode: The GOLF experiment on the SOHO mission aims to study the internal structure of the Sun by measuring the spectrum of global oscillations in the frequency range 10-7 to 10-2 Hz. Here we present the results of the analysis of the first 8 months of data. Special emphasis is put into the frequency determination of the p modes, as well as the splitting in the multiplets due to rotation. For both, we show that the improvement in S/N level with respect to the ground-based networks and other experiments is essential in achieving a very low-degree frequency table with small errors ∼ 2 parts in 10-5). On the other hand, the splitting found seems to favour a solar core which does not rotate slower than its surface. The line widths do agree with theoretical expectations and other observations. Title: Performance and Early Results from the GOLF Instrument Flown on the SOHO Mission Authors: Gabriel, A. H.; Charra, J.; Grec, G.; Robillot, J. -M.; Roca Cortés, T.; Turck-Chièze, S.; Ulrich, R.; Basu, S.; Baudin, F.; Bertello, L.; Boumier, P.; Charra, M.; Christensen-Dalsgaard, J.; Decaudin, M.; Dzitko, H.; Foglizzo, T.; Fossat, E.; García, R. A.; Herreros, J. M.; Lazrek, M.; Pallé, P. L.; Pétrou, N.; Renaud, C.; Régulo, C. Bibcode: 1997SoPh..175..207G Altcode: GOLF in-flight commissioning and calibration was carried out during the first four months, most of which represented the cruise phase of SOHO towards its final L1 orbit. The initial performance of GOLF is shown to be within the design specification, for the entire instrument as well as for the separate sub-systems. Malfunctioning of the polarising mechanisms after 3 to 4 months operation has led to the adoption of an unplanned operating sequence in which these mechanisms are no longer used. This mode, which measures only the blue wing of the solar sodium lines, detracts little from the detection and frequency measurements of global oscillations, but does make more difficult the absolute velocity calibration, which is currently of the order of 20%. Data continuity in the new mode is extremely high and the instrument is producing exceptionally noise-free p-mode spectra. The data set is particularly well suited to the study of effects due to the excitation mechanism of the modes, leading to temporal variations in their amplitudes. The g modes have not yet been detected in this limited data set. In the present mode of operation, there are no indications of any degradation which would limit the use of GOLF for up to 6 years or more. Title: Solar P-mode frequencies from the IRIS network. Authors: Gelly, B.; Fierry-Fraillon, D.; Fossat, E.; Palle, P.; Cacciani, A.; Ehgamberdiev, S.; Grec, G.; Hoeksema, J. T.; Khalikov, S.; Lazrek, M.; Loudagh, S.; Pantel, A.; Regulo, C.; Schmider, F. X. Bibcode: 1997A&A...323..235G Altcode: The Iris network for helioseismology has operated since 1989. We present tables of solar p-mode frequencies for observations taken during the four summer seasons from 1989 to 1992. This analysis uses the technique of maximum likelihood fitting and a χ_2_^2^ model for the probability density function of the spectrum. The simultaneous fitting of odd and even pairs of peaks strengthens the identification of the l=3 eigenmodes and improves the error bars on the 0-2 group. The frequencies are in good agreement with other observational results and with theoretical values for the D_0_ and the {DELTA}ν parameters of the asymptotic approximation. A decrease of 0.25+/-0.12μHz is seen between the 1989 and the 1992 data sets. The change is associated with the decrease of solar activity and is comparable with results of previous studies. Title: The state of art in helioseismic ground-based experiments Authors: Palle, P. Bibcode: 1997IAUS..181...15P Altcode: No abstract at ADS Title: New IRIS constraints on the solar core rotation. Authors: Gizon, L.; Fossat, E.; Lazrek, M.; Cacciani, A.; Ehgamberdiev, S.; Gelly, B.; Grec, G.; Hoeksema, J. T.; Khalikov, S.; Palle, P. L.; Pantel, A.; Regulo, C.; Schmider, F. -X.; Wilson, P. R. Bibcode: 1997A&A...317L..71G Altcode: Four time series of IRIS data (4 to 6 months) have been used to obtain improved measurements of the low degree (l=1,2,3) rotational splitting frequencies. Assuming that the rotation law is known in the outer layers of the Sun, we investigate the implications of IRIS splittings for the central regions. Both a one-shell and a two-shell rotation model have been considered in the solar core. A core rotating slightly faster than the outer radiative envelope provides the best fit to the data. Some evidence for the reliability of the observations is shown by the visibility of differential rotation in the l=3 multiplets. Title: Performance and first results from the GOLF instrument on SoHO Authors: Gabriel, A. H.; Charra, J.; Grec, G.; Robillot, J. -M.; Roca Cortés, T.; Turck-Chièze, S.; Ulrich, R.; Baudin, F.; Bertello, L.; Boumier, P.; Decaudin, M.; Dzitko, H.; Foglizzo, T.; Fossat, E.; García, R. A.; Herreros, J. M.; Lazrek, M.; Pallé, P. L.; Pétrou, N.; Renaud, C.; Régulo, C. Bibcode: 1997IAUS..181...53G Altcode: No abstract at ADS Title: Actual Status and Early Results from GOLF Experiment on-board SOHO Authors: Roca Cortes, T.; Gabriel, A. H.; Charra, J.; Grec, G.; Ulrich, R. K.; Turck-Chieze, S.; Robillot, J. M.; Boumier, P.; Regulo, C.; Baudin, F.; Lazrek, M.; Garcia, R. A.; Palle, P. L.; GOLF Team Bibcode: 1997ASPC..118..249R Altcode: 1997fasp.conf..249R GOLF is a resonant scattering spectrophotomer which is flying onboard SOHO. The first four months were dedicated to the commissioning and calibration of the instrument which led to the conclusion of a performance within design specification at system and subsystem levels. However, mal-functioning of the polarising mechanisms at the end of this period led to the adoption of an unplanned operating sequence in which the mechanisms are no longer used. This photometric mode, which measures at two points on the blue wing of the solar sodium lines, has very little effect on the possibility of reaching the first objective of the mission: measuring the solar spectrum of normal modes. However, the precise calibration procedure to transform the actual measurements into velocity is not trivial. The actual operating mode allows the obtention of continuous data without interruptions which is producing exceptionally noise-free p-mode spectra. Although this spectrum is being studied, the data accumulated do not allow a positive detection of the g-mode spectrum yet. On the other hand, the present mode of operation do not show any indication of degradation which could limit its use for up to 6 years or more of operation. Title: Temporal characteristics of solar p-modes. Authors: Baudin, F.; Gabriel, A.; Gibert, D.; Palle, P. L.; Regulo, C. Bibcode: 1996A&A...311.1024B Altcode: A method for ``time/frequency'' analysis is shortly described, with a discussion of its limitations in time and frequency resolution, and in sensitivity to noise in the signal. This is then applied to observational data. The data used are the luminosity measurements of the IPHIR experiment, and the velocity measurements performed at the Observatorio del Teide. The application to these two contemporary data sets confirms the reliability of the method and provides additional proof that the observed variation with time is not an effect of noise. The long and continuous data set allows to extract information on the temporal behaviour of low degree solar p-modes. The power of the modes is shown to vary strongly over a time-scale of a few days. These estimates are direct measurements from power variations, unlike those deduced from width measured in Fourier spectra. The temporal behaviour of several modes are compared, mainly showing independent behaviour, but also giving some indications of weak correlations between neighbouring modes. Title: Is the Solar Core Rotating Faster of Slower Than the Envelope? Authors: Lazrek, M.; Pantel, A.; Fossat, E.; Gelly, B.; Schmider, F. X.; Fierry-Fraillon, D.; Grec, G.; Loudagh, S.; Ehgamberdiev, S.; Khamitov, I.; Hoeksema, J. T.; Pallé, P. L.; Régulo, C. Bibcode: 1996SoPh..166....1L Altcode: The Sun is not a rigid body and it is well known that its surface rotation is differential, the polar regions rotating substantially slower than the equator. This differential rotation has been demonstrated by helioseismology to continue down to the base of the convective zone, below which it becomes closer to a rigid body rotation. Far deeper, inside the energy generating core, the rotation has generally been assumed to be much faster, keeping memory of the presumably high speed of the young Sun. However, several recent results of helioseismology have decreased this likelihood more and more, so that the core rotation could be suspected to be only marginally, or even not at all faster than the envelope. Certain results would even imply a core rotation slower than the envelope, an interesting but unlikely possibility. We present here a complete analysis of the rotational splitting of the low degree modes measured in three different time series obtained in 1990, 1991, and 1992 by the IRIS full-disk network. With a time of integration slightly longer than 4 months, the splitting has been measured by 4 different global methods on 42 doublets of l= 1, 35 triplets of l = 2, and 30 quadruplets of l = 3. With a high level of confidence, our result is consistent with a rigid solar core rotation. Title: Global Oscillations at Low Frequency from the SOHO Mission (GOLF) Authors: Gabriel, A. H.; Grec, G.; Charra, J.; Robillot, J. -M.; Roca Cortés, T.; Turck-Chièze, S.; Bocchia, R.; Boumier, P.; Cantin, M.; Cespédes, E.; Cougrand, B.; Crétolle, J.; Damé, L.; Decaudin, M.; Delache, P.; Denis, N.; Duc, R.; Dzitko, H.; Fossat, E.; Fourmond, J. -J.; García, R. A.; Gough, D.; Grivel, C.; Herreros, J. M.; Lagardère, H.; Moalic, J. -P.; Pallé, P. L.; Pétrou, N.; Sanchez, M.; Ulrich, R.; van der Raay, H. B. Bibcode: 1995SoPh..162...61G Altcode: The GOLF experiment on the SOHO mission aims to study the internal structure of the sun by measuring the spectrum of global oscillations in the frequency range 10−7 to 10−2 Hz. Bothp andg mode oscillations will be investigated, with the emphasis on the low order long period waves which penetrate the solar core. The instrument employs an extension to space of the proven ground-based technique for measuring the mean line-of-sight velocity of the viewed solar surface. By avoiding the atmospheric disturbances experienced from the ground, and choosing a non-eclipsing orbit, GOLF aims to improve the instrumental sensitivity limit by an order of magnitude to 1 mm s−1 over 20 days for frequencies higher than 2.10−4 Hz. A sodium vapour resonance cell is used in a longitudinal magnetic field to sample the two wings of the solar absorption line. The addition of a small modulating field component enables the slope of the wings to be measured. This provides not only an internal calibration of the instrument sensitivity, but also offers a further possibility to recognise, and correct for, the solar background signal produced by the effects of solar magnetically active regions. The use of an additional rotating polariser enables measurement of the mean solar line-of-sight magnetic field, as a secondary objective. Title: Comportement temporel des oscillations solaires. Authors: Baudin, F.; Gabriel, F.; Gibert, D.; Palle, P. L.; Regulo, C. Bibcode: 1995JAF....49R..52B Altcode: No abstract at ADS Title: Variation of the P-Mode Power Spectrum at Solar Activity Cycle Scales and Shorter Authors: Roca Cortés, T.; Pallé, P. L.; Régulo, C. Bibcode: 1995ESASP.376b.103R Altcode: 1995soho....2..103R; 1995help.confP.103R Disk integrated sunlight, radial velocity observations performed using a resonant scattering spectrophotometer from 1980 to 1994 at the Observatorio del Teide, have been used to calculate the monthly power spectra. Cross-correlations of each spectra with one at the minimum of the cycle are used to measure the frequency shifts. These shifts, with a peak to peak variation of 0.52±0.02 μHz, show a clear variation with the solar activity cycle that correlate very well with several activity indices. However, at shorter time scales the correlation fails. On the other hand, the amplitudes of the low-l p-modes studied at maximum and minimum of the solar cycle are anticorrelated with the activity cycle, being 30% higher at solar maximum. Using a cumulative power spectrum and a definition for the frequency cut-off of the spectrum, it is found that a significantly different result is obtained for maximum and for minimum of the solar activity cycle. Title: Temporal Behaviour of Solar P-Modes of Low Degree L Authors: Baudin, F.; Gabriel, A.; Gibert, D.; Pallé, P.; Régulo, C. Bibcode: 1995ESASP.376b.323B Altcode: 1995help.confP.323B; 1995soho....2..323B No abstract at ADS Title: Solar Core Rotation: Latest IRIS Results Authors: Fossat, E.; Lazrek, M.; Loudagh, S.; Pantel, A.; Gelly, B.; Grec, G.; Schmider, F. X.; Pallé, P. L.; Régulo, C.; Ehgamberdiev, S.; Khalikov, S.; Hoeksema, T. Bibcode: 1995ESASP.376b.261F Altcode: 1995help.confP.261F; 1995soho....2..261F No abstract at ADS Title: A Search for G-Modes Authors: Martín, I.; Pallé, P. L.; Pérez-Hernández, F.; van der Raay, H. R. Bibcode: 1995ESASP.376b.423M Altcode: 1995help.confP.423M; 1995soho....2..423M No abstract at ADS Title: Calibration and Analysis of Simulated GOLF Data Authors: Garcia, R. A.; Roca Cortés, T.; Régulo, C.; Pallé, P. L. Bibcode: 1995ESASP.376b.369G Altcode: 1995help.confP.369G; 1995soho....2..369G 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: A Measurement of the Background Solar Velocity Spectrum Authors: Palle, P. L.; Jimenez, A.; Perez Hernandez, F.; Regulo, C.; Roca Cortes, T.; Sanchez, L. Bibcode: 1995ApJ...441..952P Altcode: Ten years of continuous measurements of the radial velocity of the Sun have been used to estimate the contribution of various solar surface phenomena to the observed background solar velocity spectrum (BSVS). The characteristics of this spectrum are of great importance, as they represent the ultimate limit on the sensitivity of measurements of solar oscillations. A precise determination of this spectrum from the ground is invariably contaminated by the discontiniuity in the observations, the unavoidable effect of the Earth's atmosphere and, possibly, by the instrumentation itself. The present analysis uses observations made with a very stable instrument to allow comparison of several sets of data, collected along different phases of the solar activity cycle. The results show a high stability of the BSVS throughout the frequency ranges of interest for helioseismology and, moreover, its profile cannot be modeled using a single exponential function, as the exponent changes with frequency. The roughness of the spectrum is calculated, allowing an estimate of the required signal-to-noise ratio in order to detect an oscillation with a given amplitude. Finally, following the modeling of the expected background spectrum proposed by Harvey, the rms full disk velocity of the main solar atmospheric phenomena (granulation, mesogranulation, supergranulation, and active regions) are calculated. Despite the limitations of the procedure employed in this analysis, the main conclusion is the overall good agreement with the model, although mesogranulation seems to have been underestimated. Comparison with the different phases of the solar activity cycle reveals a different behavior of the mesogranulation, while granulation appears to be stable. Title: Solar Cycle Frequency Shifts at Low L Authors: Palle, P. L. Bibcode: 1995ASPC...76..239P Altcode: 1995gong.conf..239P No abstract at ADS Title: Results from Mark-II Spectrophotometer. Measuring Odd (l+m) Low Degree p-Modes Authors: Eff-Darwich, A.; Perez Hernandez, F.; Palle, P.; Jimenez, A.; Roca Cortes, T.; van der Raay, H. B. Bibcode: 1995ASPC...76...47E Altcode: 1995gong.conf...47E No abstract at ADS Title: Does the Solar Core Rotation Change with the Activity Cycle? Authors: Jimenez, A.; Perez Hernandez, F.; Claret, A.; Palle, P. L.; Regulo, C.; Roca Cortes, T. Bibcode: 1995ASPC...76..284J Altcode: 1995gong.conf..284J No abstract at ADS Title: On the Solar Core Rotation - IRIS Results Authors: Fossat, E.; Loudagh, S.; Gelly, B.; Grec, G.; Pantel, A.; Provost, J.; Berthomieu, G.; Ehgamberdiev, S.; Khalikov, S.; Lazrek, M.; Palle, P. L.; Regulo, C. Bibcode: 1995ASPC...76...24F Altcode: 1995gong.conf...24F No abstract at ADS Title: The Observed Background Solar Velocity Spectrum over the Solar Activity Cycle Authors: Palle, P. L.; Jimenez, A.; Martin, I.; Perez Hernandez, F.; Regulo, C.; Roca Cortes, T.; Sanchez, L. Bibcode: 1995ASPC...76..288P Altcode: 1995gong.conf..288P No abstract at ADS Title: On the Solar Core Rotation - IRIS Results Authors: Fossat, E.; Loudagh, S.; Gelly, B.; Grec, G.; Panel, A.; Provost, J.; Berthomieu, G.; Ehgamberdiev, S.; Khalikov, S.; Lazrek, M.; Palle, P. L.; Regulo, C. Bibcode: 1995ASPC...76....4F Altcode: No abstract at ADS Title: The Rotation of the Solar Core Authors: Jimenez, Antonio; Perez Hernandez, Fernando; Claret, Antonio; Palle, Pere Lluis; Regulo, Clara; Roca Cortes, Teodoro Bibcode: 1994ApJ...435..874J Altcode: The solar p-mode spectrum of very low l has already been measured with high accuracy for a sufficiently long period of time to permit the search for solar cycle variations. The longest one-site velocity observations for low l solar p-modes (Tenerife) has been used to measure the l = 1 mode splitting at the two extremes of the solar activity cycle. The results found exclude the rigid body rotation for the Sun. When taking the extreme values measured for the splitting, a solar core rotation between 2 and 4 times larger than that at the surface is obtained. Also, the observational results indicate an increase (1.3-2 times) of the rotation rate at the maximum of the solar activity cycle. Title: Variation of the Frequencies of Very Low L p-Modes Authors: Regulo, C.; Jimenez, A.; Palle, P. L.; Perez Hernandez, F.; Roca Cortes, T. Bibcode: 1994ApJ...434..384R Altcode: Radial velocity observations performed using a resonant scattering instrument from 1980 to 1993 at the Observatorio del Teide have been used to calculate the monthly power spectra of very low degree solar oscillations. Cross-correlations among the spectra allow to determine the p-mode frequency shifts along the observed period. These shifts show a clear correlation with several indices of solar activity along the 11 years cycle but, on shorter timescales, the correlation is not clear. As the size of the effect is approximately 30% higher than the one found found using high degree modes, other phenomena (probably related to magnetic fields) possibly occurring in the interior of the Sun may be involved in these solar cycle-related frequency shifts. Title: The Global Oscillation Network Group Site Survey - Part Two Authors: Hill, Frank; Fischer, George; Forgach, Suzanne; Grier, Jennifer; Leibacher, John W.; Jones, Harrison P.; Jones, Patricia B.; Kupke, Renate; Stebbins, Robin T.; Clay, Donald W.; Ingram, Robert E. L.; Libbrecht, Kenneth G.; Zirin, Harold; Ulrichi, Roger K.; Websteri, Lawrence; Hieda, Lester S.; Labonte, Barry J.; Lu, Wayne M. T.; Sousa, Edwin M.; Garcia, Charles J.; Yasukawa, Eric A.; Kennewell, John A.; Cole, David G.; Zhen, Huang; Su-Min, Xiao; Bhatnagar, Arvind; Ambastha, Aashok; Al-Khashlan, Abdulrahman Sa'ad; Abdul-Samad, Muhammad-Saleh; Benkhaldoun, Zouhair; Kadiri, Samir; Sánchez, Francisco; Pallé, Pere L.; Duhalde, Oscar; Solis, Hernan; Saá, Oscar; González, Ricardo Bibcode: 1994SoPh..152..351H Altcode: The Global Oscillation Network Group (GONG) Project will place a network of instruments around the world to observe solar oscillations as continuously as possible for three years. The Project has now chosen the six network sites based on analysis of survey data from fifteen sites around the world. The chosen sites are: Big Bear Solar Observatory, California; Mauna Loa Solar Observatory, Hawaii; Learmonth Solar Observatory, Australia; Udaipur Solar Observatory, India; Observatorio del Teide, Tenerife; and Cerro Tololo Interamerican Observatory, Chile. Title: Secular Variations in the Spectrum of Solar P-Modes Authors: Jimenez, A.; Palle, P. L.; Regulo, C.; Roca Cortes, T. Bibcode: 1994SoPh..152..253J Altcode: 1994svs..coll..253J; 1994IAUCo.143..253J The solar p-mode spectrum of very low I is measured with high accuracy for a long enough period of time so as to allow the search for solar cycle variations. In this paper solar cycle variations of the frequency and energy of the modes are confirmed. Moreover, a slight variation,within errors, of its rotational splitting with the solar cycle, is suggested. Title: Full-disk helioseismic IRIS raw data calibration. Authors: Palle, P. L.; Fossat, E.; Regulo, C.; Loudagh, S.; Schmider, F. X.; Ehgamberdiev, S.; Gelly, B.; Grec, G.; Khalikov, S.; Lazrek, M.; Sanchez, L. Bibcode: 1993A&A...280..324P Altcode: The International Research on the Interior of the Sun (IRIS) helioseismometer measures the full disk line of sight velocity of the Sun. In fact, it makes a photometric mesurement using two monochromatic spectral windows located on the wings of the D1 solar line. This is a non-linear measurement. Before a scientific exploitation of the IRIS data, the instrumental signal must be converted from non-linear photometric data into calibrated line of sight velocity. In this process, it is necessary to extract the small component due to the solar surface motions from the much larger contributions of the Earth spin, the Earth orbit, the gravitational redshift, the D1 line distortions produced by solar activity and even some telluric atmospheric effects. This paper describes the calibration method which is now used for pre-processing the IRIS data. It is the result of several iterations, and the use of one and a half years of IRIS data from one instrument, at Teide Observatory. It is certainly the best possible method to date, given the quality of the current data, and it can be regarded as valid over all the entire p-mode frequency range, and down to 100 microHz or so in the g-mode range. At lower frequencies, calibration, solar noise and merging techniques cannot be completely separated, and possible further improvements are still under investigation. Title: Modeling of integrated sunlight velocity measurements: The effect of surface darkening by magnetic fields Authors: Ulrich, R. K.; Henney, C. J.; Schimpf, S.; Fossat, E.; Gelly, B.; Grec, G.; Loudagh, S.; Schmider, F. -X.; Palle, P.; Regulo, C. Bibcode: 1993A&A...280..268U Altcode: It has been known since the work by Claverie et al. (1982) that integrated-sunlight velocities measured with the resonance scattering technique show variations with time scales of weeks to months. The cause can be understood in terms of the effects of solar activity as was pointed out by Edmunds & Gough (1983) and Andersen & Maltby (1983). The latter authors included a model calculation based on sunspot areas which showed good promise of being able to quantitatively reproduce the observed velocity shifts. We discuss in this paper a new modeling effort based on daily magnetograms obtained at the 150-ft tower on Mt. Wilson. This type of database is more quantitative than sunspot area. Similar maps of magnetically sensitive quantities will be measured on a continuous time base as part of several planned helioseismology experiments (from space with the Solar Oscillations Imagery/Michelson Doppler Imager (SOI/MDI) experiment on the Solar and Heliospheric Observatory (SOHO), see Scherrer et al. (1991) or with ground-based networks, see Hill & Leibacher (1991)). We discuss the correlations between various magnetically sensitive quantities and develop a new model for the effects of magnetic field on line profiles and surface brightness. From these correlations we integrate the line profile changes over the solar surface using observed magnetic field strengths measured at lambda 5250.2. The final output is a new model for the effects of magnetic fields on integrated sunlight velocities which we compare with daily offset velocities derived from the International Research on the Interior of the Sun (IRIS)-T instrument at the Observatorio del Teide. Title: A measurement of the I = I solar rotational splitting Authors: Loudagh, S.; Provost, J.; Berthomieu, G.; Ehgamberdiev, S.; Fossat, E.; Gelly, B.; Grec, G.; Khalikov, S.; Lazrek, M.; Palle, P.; Regulo, C.; Sanchez, L.; Schmider, F. -X. Bibcode: 1993A&A...275L..25L Altcode: A precise measurement of the l = 1 rotational splitting has been derived from the 1991 IRIS data and it leads to a moderate rotation rate in the solar core. Title: Observations of Low Degree P-Modes with Odd L+M Authors: Palle, P. L.; Perez-Hernandez, F.; Regulo, C.; Roca-Cortes, T. Bibcode: 1993ASPC...42..189P Altcode: 1993gong.conf..189P No abstract at ADS Title: On Full Disk Helioseismology Power Spectra around the Cut-Off Frequency Authors: Regulo, C.; Fossat, E.; Roca-Cortes, T.; Ehgamberdiev, S.; Gelly, B.; Grec, G.; Khalikov, S.; Lazrek, I. Khamitov M.; Palle, P. L.; Sanchez-Duarte, L. Bibcode: 1993ASPC...42..103R Altcode: 1993gong.conf..103R No abstract at ADS Title: On the acoustic cut-off frequency of the sun Authors: Fossat, E.; Regulo, C.; Roca Cortes, T.; Ekhgamberdiev, S.; Gelly, B.; Grec, G.; Khalikov, S.; Khamitov, I.; Lazrek, M.; Palle, P. I. Bibcode: 1992A&A...266..532F Altcode: Full solar disk observations of radial velocity, obtained with the IRIS network of resonant scattering spectrometers, are used to analyze the acoustic p-mode spectrum around the acoustic cut-off frequency. Three different methods are used to determine it; two use the power spectrum, while the third uses the phase spectrum. The three values measured converge to a common value of 5.55 +/- 0.1 mHz, which is higher than any theoretical prediction. Beyond this frequency, the power spectra still decreases down to 10 mHz at which point it becomes flat, showing the presence of some power due to the so-called pseudomodes which we show are the result of interference between traveling waves. The acoustic power density measured beyond the cut-off frequency makes it possible to estimate the energy deposited into the chromosphere about 10 exp 7 erg/sq cm per sec, which is high enough to compensate the losses that take place in this layer. Title: The low L solar p-mode spectrum at maximum and minimum solar activity Authors: Anguera Gubau, M.; Palle, P. L.; Perez Hernandez, F.; Regulo, C.; Roca Cortes, T. Bibcode: 1992A&A...255..363A Altcode: Velocity measurements of disc integrated sunlight obtained at the Observatorio del Teide (Izana) from 1980 throughout 1989 are used to find the frequencies and amplitudes of each p-mode with l less than 4 and n between 5 and 33. The 32 best monthly spectra obtained are averaged in two separate groups corresponding to periods with solar activity maximum and minimum. The observational p-mode frequencies differ from those predicted by standard solar models by more than their errors; however the frequency separations are in reasonable agreement. Such parameters, which give information about the core of the sun, can be determined for the maximum and the minimum of solar activity cycle. Significant differences between maximum and minimum on these parameters have not been found and they agree well with the predictions of standard models although the small observational errors achieved allow distinguishing among them. It is also found that the energy of the modes is smaller at the maximum than during the minimum of solar activity, telling us a bit more about the structure and efficiency of the sunlayers in exciting these modes. Title: Solar Radial Velocity and Oscillations as Measured by Sodium and Potassium Resonant Scattering Spectrometers Authors: Palle, P. L.; Regulo, C.; Roca-Cortes, T.; Sanchez-Duarte, L.; Schmider, F. X. Bibcode: 1992A&A...254..348P Altcode: Since the beginning of 1990, a sodium based resonance scattering spectrometer belonging to the IRIS Network has operated at Observatorio del Teide side by side with the MkI instrument (a resonance scattering spectrometer based on potassium) from the University of Birmingham and operated since 1975. A 3 month series of simultaneous data obtained in summer 1990 is the basis for this study that compares the performance of both instruments in measuring the solar radial velocity and oscillations. Interesting features of the p-modes as seen at two different levels of the solar atmosphere such as the ratio of energies per unit mass and the difference of phases are obtained. These results demonstrate that the p-modes are truly standing waves. Crosscorrelation of the spectra of the series obtained with both instruments shows the existence of signals well above the cutoff frequency of the solar atmosphere, being interpreted as travelling waves, also called pseudomodes. An estimation of the cutoff frequency gives a value of 5.6 ± 0.1 mHz, higher than theoretically predicted. Title: The Teide Observatory Authors: Palle, P. L. Bibcode: 1991SoPh..133...65P Altcode: The Teide Observatory in the Canary Islands is, at present, a well-known nucleus for solar physics research. In this contribution, the facilities at the Observatory, which now houses one of the IRIS network instruments, are presented. Title: Preliminary performance of a 4-point resonance scattering experiment to access long-period global oscillations from space Authors: Boumier, P.; Bocchia, R.; Damé, L.; Martic, M.; Pallé, P.; van der Raay, H. B.; Robillot, J. M.; Roca Cortés, T. Bibcode: 1991AdSpR..11d.199B Altcode: 1991AdSpR..11..199B The first data of a SOHO-GOLF type instrument are presented hereafter. The slopes of the solar sodium lines profiles D1 and D2, and their variations with the excursion of the working point are shown. Two methods of determining the oscillation velocity are compared, one usually used with 2-point spectrometers and one using the 4-point information. We show that the second method gives spectra which are significantly less noisy in the very low frequency range (up to 300 μHz). For higher frequencies, terrestrial atmospheric fluctuations alter the measurement, and as far as ground based instruments are concerned, the 4-point method loses its efficiency if the magnetic modulation commutation time (in our case 20 seconds) is not significantly reduced. Title: Solar p-mode frequencies. Authors: Palle, Pere L. Bibcode: 1991sia..book.1249P Altcode: The author presents some mathematical formulae which have been derived from observed frequencies and which allow the reader, not only to reproduce the observed frequencies accurately, but also to extrapolate them to limits beyond present observations. Title: The search for solar gravity modes Authors: Palle, Pere L. Bibcode: 1991AdSpR..11d..29P Altcode: 1991AdSpR..11...29P Well after the discovery of the global acoustic oscillations of the Sun, (p-modes), it was realized that another type of mode should exist in such a stratified medium: the internal gravity modes. It was also noticed that this type of mode was only providing information on the inner 40% of the Sun; precisely the region where p-modes are less sensitive to the physical conditions. This fact turned the g-modes into the most powerful tool for the investigation of the solar core.

Excepting the 160m oscillation/artifact /16/, the first observational claim of internal g-mode detection took place in 1983 /14/, and, since then, a lot of effort has been devoted to this subject both, observationally and in data analysis, and in the theoretical field. In the last seven years, three different principal data sets have been extensively analized in a search for g-modes (Tenerife, ACRIM and Stanford). Their characteristics and the results claimed from the analysis will be reviewed and discussed. However the present situation is that the discrepancies between observers suggest that the solar g-modes though probably detected, are not yet measured nor classified. What is of general agreement is the existence of signals, embedded in noise, in the low frequency range where g-modes are expected to lie. As we will emphasize in this review, we are dealing with a far different situation than for the p-modes: lower frequencies, poorer signal-to-noise ratio, etc...

Taking into account these difficulties, there is a real hope of success in the near future: with the space experiments devoted to Helioseismology on board of SOHO and the earth-based networks of helioseismic instruments. Title: Global Acoustic Oscillations on alpha Bootis Authors: Belmonte, Juan A.; Jones, Andrew R.; Palle, Pere L.; Roca Cortes, Teodoro Bibcode: 1990ApJ...358..595B Altcode: A two-week time series of precise radial velocity measurements of Alpha Bootis (Arcturus) covering 7-8 hr per night is reported. The radial barycentric velocity of the star is found to be -5021 + or - 5 m/s. When data from the whole run are jointly analyzed, several equispaced peaks in the frequency appear in the range of a few microhertz, the highest amplitude being some 60 m/s at 4.3 microhertz. The most probable frequency spacing seems to be 50 microhertz, while the frequency cutoff is around 80 microhertz. Title: An Attempt to Identify Low-L / Low-N Solar Acoustic Modes Authors: Anguera Gubau, M.; Palle, P. L.; Perez Hernandez, F.; Roca Cortes, T. Bibcode: 1990SoPh..128...79A Altcode: 1990IAUCo.121P..79A The low l solar acoustic spectrum has been measured with great accuracy (Δv/v ∼ 10−4), for intermediate radial order modes, 11 ≤ n ≤ 34 (Jiménez et al., 1986; Grec, Fossat, and Pomerantz, 1983; Pallé et al., 1986). The measurement of the frequencies of modes of lower n, up to the fundamental one, are very important as they depart from asymptotic behaviour and, therefore, put more severe constraints on solar models. However, their amplitudes are very low (under 2 cm s−1) and when compared to the solar velocity background noise (Jiménez et al., 1986), a S/N ∼ 1 is obtained. Taking advantage of the fact that lifetimes seem to be higher at lower frequencies (lower n values) (Jefferies et al., 1988; Elsworth et al., 1990), very long Doppler velocity measurements, obtained at Teide Observatory, have been used to increase S/N, therefore, providing the possibility to detect such modes. The frequencies observed are compared to those predicted by a solar model (Christensen-Dalsgaard, Däppen, and Lebreton, 1988), using the best equation of state yet computed (Mihalas, Däppen, and Hummer, 1988). Title: Acoustic Oscillations in the K2111-STAR Arcturus Authors: Belmonte, J. A.; Jones, A. R.; Palle, P. L.; Roca Cortes, T. Bibcode: 1990Ap&SS.169...77B Altcode: Simultaneous spectrometric and photometric observations have been performed, on the red giant star Arcturus (α Boo), in a search for radial velocity or luminosity variations related to global oscillations of the stellar structure. From a preliminary analysis of the spectrometric data, several frequencies have been discovered in the range from 1 to 50 μHz, the highest amplitude being of ∼60 ms-1 at 4.3 μHz. From the analysis of the photometric data, slight evidence of this variation has been found, yielding a value of ΔV/Δm=48 km s-1 mag-1. Title: Phase Differences Between Luminosity and Velocity Measurements of the Acoustic Modes Authors: Jiménez, A.; Álvarez, M.; Andersen, N. B.; Domingo, V.; Jones, A.; Pallé, P. L.; Roca Cortés, T. Bibcode: 1990SoPh..126....1J Altcode: With two photometric stations (Tenerife and Baja California) the luminosity p-mode spectrum at different wavelengths has been identified. After a coherence analysis between data from both stations to verify the solar origin of the peaks identified in luminosity, a comparative study with simultaneous velocity measurements (obtained at Tenerife only) has also been made. As a result the frequency dependence of the phase difference between luminosity and velocity p-modes has been obtained that is interpreted in terms of a nonadiabatic behaviour of the solar atmosphere. The amplitude ratios between luminosity and velocity p-modes have also been obtained. All these results are compared with theoretical expectations. Title: Frequencies, Linewidths, and Splittings of Low-Degree Solar p-Modes Authors: Pallé, P. L.; Régulo, C.; Roca Cortés, T. Bibcode: 1990LNP...367..189P Altcode: 1990psss.conf..189P The measurement of frequencies, linewidths, and splittings of low degree solar p-modes is a difficult task due, firstly, to time scales involved and, secondly, to the spurious presence of side lobes when data is not collected continuously. However, a long set of observations have been obtained at Observatorio del Teide: a total of 52 months of data, spread over 12 years (1977 to 1989), from which the best ones have been selected. These data allows averaging of power spectra, therefore giving statistical significant profiles for the p-modes, which can be fitted to appropriate functions (i.e. Lorentzian). Such analysis is applied to the data mentioned before and preliminary results of the aforementioned parameters are obtained. Title: Variations of the Low / Solar Acoustic Spectrum Correlated with the Activity Cycle Authors: Pallé, Pere L.; Régulo, C.; Roca Cortés, T. Bibcode: 1990ASSL..159..349P Altcode: 1990insu.conf..349P; 1990IAUCo.121..349P No abstract at ADS Title: The Spectrum of Solar p-Modes and the Solar Activity Cycle Authors: Pallé, P. L.; Régulo, C.; Roca Cortés, T. Bibcode: 1990LNP...367..129P Altcode: 1990psss.conf..129P Solar cycle variations on the power and frequencies of the low l p-mode solar acoustic oscillations are investigated using an extensive set of observations obtained at Observatorio del Teide (Izaña, Tenerife). The radial velocity of integrated sunlight has been monitored, by means of a resonant scattering spectrophotometer, at several epochs (basically each year) from 1977 to 1989. The latest data (1988 and 1989) confirm previously found results (Pallé et al., 1988, 1989a,b): a) A variation of nearly 40% peak to peak in the power of the low l solar p-modes, being higher when the solar activity is at its minimum. b) A null variation in frequency for l = 0 and a decrease of ≈ 0.5 µ.Hz for l = 1 when solar activity goes from maximum to minimum (similar results for l = 2 and l = 3) by using a cross-correlation technique. Title: Solar cycle induced variations of the low L solar acoustic spectrum. Authors: Palle, P. L.; Regulo, C.; Roca Cortes, T. Bibcode: 1989A&A...224..253P Altcode: Doppler velocity data are used to study solar cycle variation of the frequencies of solar acoustic oscillations from 1977 to 1988. The results show a clear shift in frequency of the cross-correlation peaks of -0.37 + or - 0.04 microHz peak to peak as the solar activity cycle progresses from maximum to minimum. This effect is dependent on the l value of the modes. The results suggest that, as low l modes penetrate deeply into the sun's interior, there are structural changes correlated with the solar activity cycle. Title: Search for radial velocity variations in rapidly oscillating AP star using the Fabry-Perot interferometric stellar oscillation spectrometer. Authors: Belmonte, J. A.; Bell, C. R.; Leeper, M.; Palle, P. L.; Pietraszewski, K. A. R. B.; Renton, R. E.; Roca Cortes, T. Bibcode: 1989A&A...221...41B Altcode: Radial velocity measurements of a group of Ap stars were obtained in May and December 1987 using a Fabry-Perot interferometric stellar oscillation spectrometer that has been improved to enable the instrument to be referenced to the Cd blue line. Observations of the rapidly oscillating Ap stars 33 Lib and HR 1217 were analyzed in order to search for radial velocity variations corresponding to the photometric periods found in these stars. The radial velocity and photometric data sets have been reduced with the aid of a weighted sine wave fitting routine. For HR 1217, a peak at 2.72 mHz and an amplitude of about 240 m/s are found. Title: Observations of solar p-modes with L of not greater than 5 Authors: Palle, P. L.; Perez Hernandez, F.; Roca Cortes, T.; Isaak, G. R. Bibcode: 1989A&A...216..253P Altcode: Results are presented for the sun's radial velocity in integrated sunlight. A resonant scattering spectrometer has been used to determine the frequencies and amplitudes of p-modes with spherical harmonics of degree (l) of less than 3, and a second spectrophotometer, which observes part of the sun by means of a spatial filter, has been used to measure the frequencies and amplitudes of p-modes with l of not greater than 5. The frequencies at both ends of the p-mode 5-minute oscillations with l of between 3 and 5, inclusively, are obtained with greater precision than previous determinations. Title: The 160 Minute Solar Oscillation: an Artifact? Authors: Elsworth, Y. P.; Jefferies, S. M.; McLeod, C. P.; New, R.; Palle, P. L.; van der Raay, H. B.; Regulo, C.; Roca Cortes, T. Bibcode: 1989ApJ...338..557E Altcode: Analysis of data obtained over the years 1980-1985 are analyzed to show that the period of the 160-minute signal is indeed 160.00 minutes. It is demonstrated that this signal may be simulated by a slightly distorted diurnal sine wave such as that occasioned by differential atmospheric extinction. Title: Solar oscillations as seen in the Na I and K I absorption lines. Authors: Isaak, G. R.; McLeod, C. P.; Palle, P. L.; van der Raay, H. B.; Roca Cortes, T. Bibcode: 1989A&A...208..297I Altcode: Data on the solar p modes observed simultaneously in the solar NaI and KI absorption lines were obtained in 1985 by operating two independent resonant scattering spectrometers at the same site (Observatorio del Teide, Tenerife). Since the abundances of the ground state atoms of these two elements are not the same, different depths of the solar photosphere are sampled. A comparison of the data obtained is given. Title: Frequency shift of solar p-modes as seen by cross-correlation analysis. Authors: Palle, Pere L.; Regulo, C.; Roca Cortés, Teodoro Bibcode: 1988ESASP.286..285P Altcode: 1988ssls.rept..285P Data obtained at the Observatorio del Teide (Izaña, Tenerife) during the years 1978 to 1988 using a resonant scattering spectrophotometer, is analyzed to look for variations of the low degree p-mode frequencies along the solar cycle. The analysis based on the cross-correlation of power spectra leads to the conclusion that the variation of its maximum correlation correlates well with the solar cycle. An overall variation, from minimum to maximum solar activity, of 0.5±0.1 μHz is found, when low l modes are considered. Moreover, this effect depends on the l values of the modes being absent for l = 0 and of 0.7±0.1 μHz for l = 1. Therefore, other interpretations than a simple frequency shift are plausible, such as different amplitudes between modes in the same multiplet of an asymmetric change of the splitting along the solar cycle. Title: Solar Luminosity Oscillation Telescope (SLOT). Authors: Andersen, Bo Nyborg; Domingo, V.; Jones, A. R.; Korzennik, Sylvain G.; Jimenez, A.; Palle, Pere L.; Regulo, C.; Roca Cortés, Teodoro Bibcode: 1988ESASP.286..175A Altcode: 1988ssls.rept..175A Low degree l = 0-2 solar p-modes have been detected with the SLOT instruments at Izaña and Baja California. The main source of noise for these ground based observations is in the terrestrial atmosphere. However, the data acquisition system still has to have very slow intrinsic noise. The authors describe how this is achieved in the SLOT instruments. They also give a general description of the design and operating principles of the photometers and data acquisition system. Title: High precision velocity observations of Arcturus using the 7699 Å line of potassium. Authors: Innis, J. L.; Isaak, G. R.; Brazier, R. I.; Belmonte, Juan A.; Palle, Pere L.; Roca Cortés, Teodoro; Jones, A. R. Bibcode: 1988ESASP.286..569I Altcode: 1988ssls.rept..569I The K giant Arcturus (α Boo) was observed with the Birmingham double magneto-optical filter spectrometer using the GHRIL facility at the Nasmyth focus of the 4.2 m William Herschel Telescope of the Observatorio del Roque de los Muchachos in 1988 April - May. Approximately 80 hours of data were obtained over a 2 week interval. The authors' preliminary analysis of the data shows the presence of the large (≡200 m s-1) amplitude velocity variation reported earlier by other observers. However, this more extensive data set strongly suggests that this variation is not singly periodic, as was previously indicated. The authors present some speculative comments as to the nature of this variation, and the implications for stellar seismology. Title: Can solar g-modes be identified from ground-based velocity measurements? Authors: Garcia, C.; Palle, Pere L.; Roca Cortés, Teodoro Bibcode: 1988ESASP.286..353G Altcode: 1988ssls.rept..353G After ten years of helioseismology research the question of whether or not solar g modes can be detected and identified from ground observations is still unclear. The limitation imposed by the earth's atmosphere, the background solar noise spectrum at low frequencies, and a poor theoretical knowledge of these modes are some of the reasons. Using the best uninterrupted full disk velocity measurements obtained over the period 1984 - 1987, signals with amplitudes less than 5 cm/s are found in the g modes spectral region. Cross-correlation and other techniques used to detect stable signals (g modes) show negative results which allow to put an upper limit to their amplitudes and/or lifetimes. Title: Linewidth of low degree acoustic modes of the Sun. Authors: Elsworth, Y. P.; Isaak, G. R.; Jefferies, S. M.; McLeod, C. P.; New, R.; Palle, Pere L.; Regulo, C.; Roca Cortés, Teodoro Bibcode: 1988ESASP.286...27E Altcode: 1988ssls.rept...27E Estimates of the spectral linewidths of low degree (l = 0 and l = 1), "5 minute" p-modes obtained from Doppler shift observations in 1984, 1986 and 1987 are reported. The observed linewidths increase from 0.5 μHz at 2000 μHz to 3.8 μHz at 4300 μHz for l = 0. Comparison with other data suggest that for a given frequency the linewidth increases with increasing l value. On the assumption that the linewidth is substantially due to damping processes the linewidths are consistent with e-folding times between 3.7 and 0.5 days. Title: The GONG site survey. Authors: Hill, F.; Ambastha, A.; Ball, W.; Duhalde, O.; Farris, D.; Fischer, G.; Hieda, L.; Zhen, Huang; Ingram, B.; Jackson, P.; Jones, H.; Jones, W.; Kennewell, J.; Kunkel, W.; Kupke, R.; Labonte, B.; Leibacher, J.; Libbrecht, K.; Lu, W.; Morrison, L.; Odell, C.; Pallé, P.; Saá, O.; Sousa, E.; Stebbins, T.; Xiao, Suming; GONG Site Survey Team Bibcode: 1988ESASP.286..209H Altcode: The Global Oscillation Network Group (GONG) project is planning to place six observing stations around the world to observe the solar oscillations as continuously as possible. This paper describes the procedures that are being used to select the six sites. The latest results of measurements of cloud cover obtained by networks of 6 (out of 10) radiometers show a duty cycle of over 93%, with the first diurnal sidelobe in the window power spectrum suppressed by a factor of 400. The results are in good agreement with the predictions of a computer model of the expected cloud cover at individual sites. Title: Effect of atmospheric extinction on solar radial velocity measurements. Authors: Belmonte, Juan A.; Elsworth, Y. P.; Isaak, G. R.; New, R.; Palle, Pere L.; Roca Cortés, Teodoro Bibcode: 1988ESASP.286..177B Altcode: 1988ssls.rept..177B Differential extinction across the Earth's atmosphere affects astronomical photometry in a well known way. Under the same circumstances when a rotating extended object is observed spectrometrically, a residual radial velocity is obtained which varies during the day. In the case of integral sunlight observations, this effect has been calculated along the day in all possible observing situations during the year. Applications to real observations are shown and discussed leading to some conclusions specially relevant to ground-based networks. Title: Rotational splitting of low l solar p-mode. Authors: Palle, Pere L.; Pérez Hernández, F.; Regulo, C.; Roca Cortés, Teodoro Bibcode: 1988ESASP.286..125P Altcode: 1988ssls.rept..125P Rotational splitting measurements of l < 5 p-modes are calculated using different sources of data. For l = 1, data obtained from years 1981 to 1985 is used to find out the stretches where each particular mode remains excited, then its splitting is measured and the mean found. Cross-correlation of power spectra confirms these finding, and this method is used to look for the l = 2 splitting. For 2 < l < 5 only one month of data is available and superposition of peak structures gives an upper limit for their splitting. Title: Solar luminosity oscillations from two stations and correlation with velocity measurements. Authors: Jimenez, A.; Palle, Pere L.; Roca Cortés, Teodoro; Andersen, N. B.; Domingo, V.; Jones, A. R.; Alvarez, M.; Ledezma, E. Bibcode: 1988ESASP.286..163J Altcode: 1988ssls.rept..163J Since 1984 the measurements of a quadrupole photometer sites at the Observatorio del Teide (Izaña, Tenerife) have made it possible to identify the p-mode luminosity spectrum with simultaneous velocity observations. Comparing this data, the adiabatic behaviour of solar atmosphere and theoretical expectations from solar models have been tested. Now, in order to increase the signal-to-noise ratio and reduce the sidebands due to the night-time data gaps, a second identical photometer was set-up in December 1987, at the Observatorio de San Pedro Mártir (Baja California Norte, Mexico). The first results of the observations of these two stations are analyzed and compared with simultaneous velocity measurements. Title: The search for radial velocity variations in rapidly oscillating Ap stars using the Fabry-Perot interferometric stellar oscillation spectrometer (FP-ISOS). Authors: Leeper, M.; Bell, C. R.; Pietraszewski, K. A. R. B.; Renton, R. E.; Belmonte, J. A.; Pallé, P. L.; Roca Cortés, T. Bibcode: 1988ESASP.286..587L Altcode: 1988ssls.rept..587L Radial velocity measurements were taken of a group of Ap stars using a newly improved FP-ISOS. Observations were made using the 1.5 m TCS on Tenerife in May 1987 and December 1987. The already known rapidly oscillating Ap stars 33 Lib and HR 1217 were observed in order to search for radial velocity variations corresponding to the photometric periods found in these stars. Simultaneous photometric measurements were made on HR 1217 on the last two nights using the nearby 0.5 m telescope. The radial velocity and photometric data sets have been reduced using a weighted sine wave fitting routine. Promising results have been obtained for HR 1217, while results obtained for the other Ap stars observed do not allow to any conclusion. Data taken several years ago on α Cir was re-examined and the results obtained are also discussed. Title: Further implications of solar p-modes as measured in Na and K resonance lines. Authors: Palle, Pere L.; Pérez Hernández, F.; Roca Cortés, Teodoro Bibcode: 1988ESASP.286..513P Altcode: 1988ssls.rept..513P The ratios between the amplitudes of p-modes measured simultaneously in the Na and K resonance lines are compared with the expected ratios for adiabatic waves at two different levels in the atmosphere. The results agree within errors with the energy decaying solution for the waves at the photosphere. Title: Search for rapid oscillations in the northern Ap stars HD 62140, HD 81009 and HD 22374. Authors: Belmonte, Juan A.; Palle, Pere L.; Roca Cortés, Teodoro; Shoch, Fritz Bibcode: 1988ESASP.286..609B Altcode: 1988ssls.rept..609B High-speed photometric observations have been performed of the Ap stars HD 62140 (49 Cam), HD 81009 and HD 22374 for more than 60 hours in October and December 1986 using the 1 m-JKT at the Observatorio del Roque de los Muchachos (ORM) and the 1.5 m-TCS of the Observatorio del Teide (OT), Canary Islands (Spain). Photometric measurements in the B band were reduced and the residuals obtained were subjected to a harmonic analysis searching for periodicities in the range of a few minutes to 2 hours. There is some evidence that the star 49 Cam is oscillating. HD 81009 and HD 22374 were observed in order to confirm some traces of oscillation present in earlier observations however, these possible oscillations did not repeat in the new data. Title: Luminosity Oscillations Imager (LOI). Authors: Andersen, Bo Nyborg; Domingo, V.; Jones, A. R.; Jimenez, A.; Palle, Pere L.; Regulo, C.; Roca Cortés, Teodoro Bibcode: 1988ESASP.286..385A Altcode: 1988ssls.rept..385A The VIRGO (Variability in Irradiance and Gravity Oscillations) investigation has been selected to fly on ESA's SOHO mission. One of the components of the VIRGO is a small imaging solar photometer. This instrument, the Luminosity Oscillations Imager (LOI), will observe the solar radiance with 12 pixels resolution. A prototype of the LOI has been developed at ESTEC. This prototype was built mainly to test possible detector configurations, the data acquisition system and the internal guider. The prototype has been operating at Izaña, Tenerife since April this year. Title: Diurnal photometric conditions at Teide observatory and long-term solar irradiance variations Authors: Andersen, B.; Domingo, V.; Jiménez, A.; Jones, A.; Korzennik, S.; Pallé, P. L.; Pérez Hernández, F.; Régulo, C.; Roca Cortés, T.; Tomás, L. L. Bibcode: 1988SoPh..116..391A Altcode: Monochromatic extinction coefficients at four wavelengths have been obtained over a period of more than two years at the Observatorio del Teide (Izaña Tenerife) using a full disc, direct sunlight, quadruple photometer devoted to the detection of integral luminosity oscillations of the Sun. The mean extinction coefficients (0.13 at 500 nm) show a seasonal variation of about 15%, the best atmospheric conditions being in winter and autumn. Moreover, in anyone day the extinction coefficient in the afternoon is always lower than the one in the morning by ∼ 7%. A one-year period fluctuation, with an amplitude of ∼ 0.035 mag, has been identified in the instrumental magnitudes outside the atmosphere, and is interpreted as the variation produced by the different Sun-Earth distance from winter to summer. Finally, the study made to detect periodic time fluctuations in both, Sun's magnitude and extinction coefficients, has given null results at levels of ∼ 0.04 and ∼ 1.8%, respectively. Title: Frequency stability of solar oscillations Authors: Jefferies, S. M.; Pallé, P. L.; van der Raay, H. B.; Régulo, C.; Roca Cortés, T. Bibcode: 1988Natur.333..646J Altcode: Changes in the internal structure of the Sun over the 11-year magnetic activity cycle could be reflected in the eigenfrequencies of the acoustic p-modes. The first tentative experimental evidence was presented in 19841 and subsequently an analysis of ACRIM solar intensity data2 suggested a decrease of frequencies of the 5-min solar p-modes between 1980 and 1984 of ~0.4 μHz. Recently3-6 further experimental data have provided conflicting results; frequency increases, decreases and stability have all been reported. Title: The observed background solar velocity noise Authors: Jimenez, A.; Palle, P. L.; Perez Hernandez, F.; Regulo, C.; Roca Cortes, T. Bibcode: 1988A&A...192L...7J Altcode: Using accurate radial velocity observations of integral sunlight, the background solar velocity noise has been measured at different frequencies of interest for solar oscillations within a frequency interval between 10-7 and 10-2Hz. Comparison with a numerical model, simulating the most important solar processes: granulation, mesogranulation, supergranulation and active regions, with associated velocity fields shows good agreement at the amplitudes and their, already known, characteristic time scales. Title: Correlation between velocity and luminosity measurements of solar oscillations Authors: Jimenez, A.; Palle, P. L.; Roca Cortes, T.; Domingo, V. Bibcode: 1988A&A...193..298J Altcode: Following the work started in 1984 to detect the solar intensity oscillations from ground (Jimenez et al., 1986), simultaneous velocity and intensity observations of 16 contiguous days of very high atmospheric quality obtained at Izana (Tenerife) have been analyzed. The frequencies of the p-mode intensity spectrum at three channels (500, 680 and 870 nm) and those of the velocity spectrum have been obtained. Amplitude ratios in the intensity measurements give results of 1.6 and 2.2 when comparing the last two channels with the first one, and their relative phases give a null result at any frequency in the 5 minute range. The relative phases between luminosity and intensity measurements give a mean result of -120 degrees. Finally, the ratio of the amplitudes of the intensity oscillations to the velocity ones correlates very well with theoretical expectations and it yields a fractional variation of the effective temperature of 2 x 10 to the -6th. Title: Search for Oscillations in Some Ap-Stars Authors: Belmonte, J. A.; Palle, P. L.; Roca-Cortes, T. Bibcode: 1988IAUS..123..265B Altcode: Photometric observations of some Ap stars with a 50 cm telescope have been carried out at Izaña (Tenerife) in February 1986. The stars observed were, generally, magnetic-cool Ap stars. A search for global oscillations in the range 3 to 15 minutes has been undertaken and they seem to be present in some of the stars observed. Title: Search for Solar G-Modes from 1981-1985 Authors: Palle, P. L.; Roca-Cortes, T. Bibcode: 1988IAUS..123...79P Altcode: Analysis of solar velocity data obtained at Izaña (Tenerife) over the years 1981 - 1985, has shown the existence of significant signals in the frequency range 25 - 125 μHz. Several ways of analyzing the data have been used in order to interpret these as solar internal gravity modes of degree l ≤ 3. Title: Splitting of the Low L Solar P-Modes Authors: Jefferies, S. M.; McLeod, C. P.; van der Raay, H. B.; Palle, P. L.; Roca-Cortes, T. Bibcode: 1988IAUS..123...25J Altcode: An analysis of full disc line of sight velocity data yield line splitting values of the low l-value non-radial modes. Possible variations of the line splitting with the solar cycle are investigated. Title: Solar Cycle Dependence of Solar P-Modes Authors: Isaak, G. R.; Jefferies, S. M.; McLeod, C. P.; New, R.; van der Raay, H. B.; Palle, P. L.; Regulo, C.; Roca-Cortes, T. Bibcode: 1988IAUS..123..201I Altcode: Data obtained at Izaña (Tenerife) and Haleakala (Maui), using optical resonant scattering with a potassium vapour cell over the years 1980 - 84, are used to determine the frequencies of the low l p modes. Possible variation in these frequencies with the solar cycle are investigated. Title: Variations in the Mean Line-Of Velocity of the Sun - 1976-1985 Authors: Jimenez, A.; Palle, P. L.; Regulo, C.; Roca-Cortes, T.; Elsworth, Y. P.; Isaak, G. R.; Jefferies, S. M.; McLeod, C. P.; New, R.; van der Raay, H. B. Bibcode: 1988IAUS..123..215J Altcode: Measurements of the line of sight velocity of the sun with respect to earth have been obtained at Izaña (Tenerife) during the years 1976 to 1985. The mean values found for each year show a trend of ≡30 m/s from minimum to maximum. Their mean value is of 583.1±0.2 m/s which is 92% of the gravitational redshift predicted by theory and their variation seems to be related to the solar cycle with the clear exception of 1985. Title: Earthbased Observations of Solar Luminosity Oscillations Authors: Jimenez, A.; Palle, P. L.; Perez-Hernandez, F.; Regulo, C.; Roca-Cortes, T.; Domingo, V.; Korzennik, S. Bibcode: 1988IAUS..123...71J Altcode: Earth based multichannel photometry of integral sunlight has been obtained at Izaña (Tenerife) during 1984 - 1986. Power spectra of the solar luminosity variations of individual days show power in the 5 minute interval above noise at a level comparable to SMM data. When combining contigous days of data the signature of p mode solar oscillations spectrum appears, although individual peak identification is difficult. Title: Experience in Operating a Limited Global Network of Stations Measuring Full-Disc Oscillations of the Sun Authors: Elsworth, Y. P.; Isaak, G. R.; Jefferies, S. M.; McLeod, C. P.; New, R.; van der Raay, H. B.; Palle, P. L.; Regulo, C.; Roca-Cortes, T. Bibcode: 1988IAUS..123..535E Altcode: Details are given about the operation of a two station network and of a new semi-automatic station which has recently been added. Comparison is made with predicted duty cycles. A possible way of quantifying the sky quality is also given. Title: Comparison of Solar Oscillation Data Obtained from a Study of the NA and K Fraunhoffer Absorption Lines Authors: Isaak, G. R.; McLeod, C. P.; van der Raay, H. B.; Palle, P. L.; Roca-Cortes, T. Bibcode: 1988IAUS..123...53I Altcode: Two independent resonant scattering spectrometers, one using a sodium and the other a potassium vapour cell, were operated simultaneously at the same site. Due to the differing abundances of ground state atoms of these two elements different depths of the photosphere are sampled. An inter-comparison of solar p modes obtained with these spectrometers is given. Title: The Solar Oscillations Spectrum and the Solar Cycle Authors: Jimenez, A.; Palle, P. L.; Perez, J. C.; Regulo, C.; Roca-Cortes, T.; Isaak, G. R.; McLeod, C. P.; van der Raay, H. B. Bibcode: 1988IAUS..123..205J Altcode: During the summer seasons of the years 1977 to 1985 daily velocity measurements of solar global oscillations have been obtained using a resonant scattering spectrometer. After calculating the power spectra of the daily residuals, the mean for each season is found. Several discrete frequency intervals are defined in the spectrum. The mean power in these intervals and the cut-off frequency of the p-mode spectrum, determined for each year, are correlated with the solar activity cycle. Furthermore, several series of 13 contiguous days for each year are analyzed. Title: The 13-DAY Period Oscillation and the Solar Cycle Authors: Jimenez, A.; Palle, P. L.; Regulo, C.; Roca-Cortes, T.; Isaak, G. R.; McLeod, C. P.; van der Raay, H. B. Bibcode: 1988IAUS..123..211J Altcode: From the analysis of radial velocity measurements of the Sun, obtained at Izaña from 1976 to 1985, stable periods longer than 1 day, have been found in the observed signal. The appearance of an oscillation with a 13 day period has been confirmed. The comparison, for 1981 - 84, of the observations with a calibrated numerical model of the passage of inhomogeneities (spots and plages) on the solar surface, shows that the signal is not only due to this effect. It is believed that a velocity field, probably related to the surface inhomogeneities, contributes to the observed signal. Title: On the 160-MINUTE Oscillation Authors: Palle, P. L.; Roca-Cortes, T. Bibcode: 1988IAUS..123...75P Altcode: Solar velocity data collected at Izaña (Tenerife) over the years 1980 - 1985 have been used to search for the 160 minute oscillation. The peculiar behaviour of the ninth harmonic of a day, in amplitude and phase, suggests the existence of a solar signal with a 160.02±0.01 minute period, which can be interpreted as a g-mode. Title: Search for solar g modes. Authors: Palle, P. L.; Roca Cortes, T.; Isaak, G. R.; van der Raay, H. B. Bibcode: 1987PAICz..66..177P Altcode: 1987eram....1..177P Using a resonant scattering spectrophotometer the authors measured the radial velocity of the Sun at the K I 769.9 nm line with very high resolution and temporal stability. The observations carried out at Izaña (Tenerife) continuously for the last three years, have been used to search for solar g modes. Individual peaks, well above noise level, are identified and their frequencies are likely to correspond with g modes. Title: The Limb Shift Effect and its Variation with the Solar Cycle Authors: Anguera, M.; Pallé, P. L.; Régulo, C.; Roca Cortés, T.; Isaak, G. R.; McLeod, C. P.; van der Raay, H. B. Bibcode: 1987rfsm.conf...24A Altcode: The radial velocity limb shift effect has been measured for the K I 7699 Å line using a resonant scattering spectrophotometer in the summer of 1982. On the other hand, using integral sunlight, the line of sight velocity has been measured during the years 1976 to 1986 and the gravitational redshift determined. This value shows a variation over those years and, when compared with the phase of the solar activity cycle, the most probable interpretation is a change of the limb shift effect with the cycle. Title: Ground-based measurements of solar intensity oscillations Authors: Jimenez, A.; Palle, P. L.; Roca Cortes, T.; Domingo, V.; Korzennik, S. Bibcode: 1987A&A...172..323J Altcode: Ground-based multichannel photometry of integral sunlight has been obtained at Izaña (Tenerife) during three months in 1984 with a photometer built at ESTEC. Power spectra of solar irradiance variations of individual days show power in the 5 min band just above noise at a level comparable to the one found from the SMM data (Woodard and Hudson, 1983). Previous similar ground work had never achieved the signal level required at the 5 min interval. When combining the best 7 contiguous days of data, the signature of p mode solar oscillations spectra appears, but individual identification is difficult due to a low signal-to-noise ratio. Title: The global oscillation spectrum of the sun. II - The observed low L high N solar p-mode spectrum Authors: Palle, P. L.; Perez, J. C.; Regulo, C.; Roca Cortes, T.; Issak, G. R. Bibcode: 1986A&A...170..114P Altcode: Using data from observing seasons 1977 through 1984, an analysis of the low l, high n p-mode solar spectra is made with a 0.9 μHz resolution. Frequencies and amplitudes of modes of l < 3 and 11 < n < 33 are determined for each observing season. No clear variation of the frequencies at the 1 μHz level is found and the amplitudes remain constant to ∼ 20%. The frequency spacings between different modes are compared over the solar cycle, as are the constants in Tassoul's asymptotic formula evaluated for each season: no conclusive variations are found. Title: The global oscillation spectrum of the sun. I - Analysis of daily power spectra of velocity measurements Authors: Palle, P. L.; Perez, J. C.; Regulo, C.; Roca Cortes, T.; Isaak, G. R. Bibcode: 1986A&A...169..313P Altcode: Daily observations of solar global oscillations using a resonant scattering spectrometer have been obtained by observing integral sunlight during the summer seasons of the years 1977 to 1984. The power spectra of the daily residuals are calculated and the mean for each observing season is found. Several discrete frequency intervals are defined in the spectrum which yield information on the characteristics of the p-mode and noise levels. The power in these intervals and the cut-off frequency of the p-mode spectrum determined for each year, show no correlation with the solar activity cycle. Title: A liquid crystal modulator Authors: Eccles, D. G.; Elsworth, Y.; van der Raay, H. B.; Palle, P. L.; Roca Cortes, T. Bibcode: 1986ASIC..169..343E Altcode: 1986ssds.proc..343E The use of a liquid crystal as an optical modulator for use with a resonant scattering spectrometer has been investigated. Preliminary data indicate that using this simple device velocity signals corresponding to 5 minute oscillations have been detected. Title: The radial velocity of the sun as a star and the solar cycle Authors: Jiménez, A.; Pallé, P. L.; Régulo, C.; Roca Cortés, T.; Isaak, G. R.; McLeod, C. P.; van der Raay, H. B. Bibcode: 1986AdSpR...6h..89J Altcode: 1986AdSpR...6...89J Radial velocity measurements of the sun as a star using a resonant scattering spectrometer have been obtained at Izan~a (Tenerife) during long observing seasons from 1976 to 1985. Its analysis shows that except for the global oscillations with periods shorter than one day there are stable signals with longer periods: at ~13 days with mean amplitude of ~ 3 m/s (it changes with the solar cycle) and another one of ~ 15 m/s amplitude which shows a temporal variation of various years related to the solar cycle. The first signal has a partial explanation as an effect produced by the passage of active regions through the visible surface of the sun but it does not completely explain the observed signal. The second one, related to the limb shift, is probably due to changes in the convection zone in connection with the solar cycle.