Author name code: leroy ADS astronomy entries on 2022-09-14 =author:"Leroy, B." ------------------------------------------------------------------------ Title: VizieR Online Data Catalog: MiMeS survey of magnetism in massive stars (Wade+, 2016) Authors: Wade, G. A.; Neiner, C.; Alecian, E.; Grunhut, J. H.; Petit, V.; de Batz, B.; Bohlender, D. A.; Cohen, D. H.; Henrichs, H. F.; Kochukhov, O.; Landstreet, J. D.; Manset, N.; Martins, F.; Mathis, S.; Oksala, M. E.; Owocki, S. P.; Rivinius, T.; Shultz, M. E.; Sundqvist, J. O.; Townsend, R. H. D.; Ud-Doula, A.; Bouret, J. -C.; Braithwaite, J.; Briquet, M.; Carciofi, A. C.; David-Uraz, A.; Folsom, C. P.; Fullerton, A. W.; Leroy, B.; Marcolino, W. L. F.; Moffat, A. F. J.; Naze, Y.; St, Louis N.; Auriere, M.; Bagnulo, S.; Bailey, J. D.; Barba, R. H.; Blazere, A.; Bohm, T.; Catala, C.; Donati, J. -F.; Ferrario, L.; Harrington, D.; Howarth, I. D.; Ignace, R.; Kaper, L.; Luftinger, T.; Prinja, R.; Vink, J. S.; Weiss, W. W.; Yakunin, I. Bibcode: 2016yCat..74560002W Altcode: To initiate the observational component of the MiMeS project, the collaboration was awarded a 640 hour Large Program (LP) with ESPaDOnS. This award was followed by LP allocations with Narval (137 nights, or 1213 hours), and with HARPSpol (30 nights , or 280 hours).

The TC sample (summarized in Table 4) consists of stars that were established or suspected to be magnetic at the beginning of the project. The majority of these stars are confirmed period ic variables with periods ranging from approximately 1 d to 1.5 years, with the majority having a period of less than 10 days so that they are suitable candidates for observational monitoring and mapping.

(1 data file). Title: The magnetic field of the double-lined spectroscopic binary system HD 5550 Authors: Alecian, E.; Tkachenko, A.; Neiner, C.; Folsom, C. P.; Leroy, B. Bibcode: 2016A&A...589A..47A Altcode: 2016arXiv160107762A Context. The origin of fossil fields in intermediate- and high-mass stars is poorly understood, as is the interplay between binarity and magnetism during stellar evolution. Thus we have begun a study of the magnetic properties of a sample of intermediate-mass and massive short-period binary systems as a function of binarity properties.
Aims: This paper specifically aims to characterise the magnetic field of HD 5550, a double-lined spectroscopic binary system of intermediate mass.
Methods: We gathered 25 high-resolution spectropolarimetric observations of HD 5550 using the instrument Narval. We first fitted the intensity spectra using Zeeman/ATLAS9 LTE synthetic spectra to estimate the effective temperatures, microturbulent velocities, and the abundances of some elements of both components, as well as the light ratio of the system. We then applied the multi-line least-square deconvolution (LSD) technique to the intensity and circularly polarised spectra, which provided us with mean LSD I and V line profiles. We fitted the Stokes I line profiles to determine the radial and projected rotational velocities of both stars. We then analysed the shape and evolution of the V profiles using the oblique rotator model to characterise the magnetic fields of both stars.
Results: We confirm the Ap nature of the primary, which has previously been reported, and find that the secondary displays spectral characteristics typical of an Am star. While a magnetic field is clearly detected in the lines of the primary, no magnetic field is detected in the secondary in any of our observations. If a dipolar field were present at the surface of the Am star, its polar strength must be below 40 G. The faint variability observed in the Stokes V profiles of the Ap star allowed us to propose a rotation period of 6.84-0.39+0.61 d, which is close to the orbital period (~6.82 d), suggesting that the star is synchronised with its orbit. By fitting the variability of the V profiles, we propose that the Ap component hosts a dipolar field inclined with the rotation axis at an angle β = 156 ± 17 ° and a polar strength Bd = 65 ± 20 G. The field strength is the weakest known for an Ap star.

Based on the BinaMIcS Large Programme (PI: C. Neiner, runID: L131N02) obtained at the Telescope Bernard Lyot (USR5026) operated by the Observatoire Midi-Pyrénées, Université de Toulouse (Paul Sabatier), Centre National de la Recherche Scientifique of France. Title: Weak magnetic field, solid-envelope rotation, and wave-induced N-enrichment in the SPB star ζ Cassiopeiae Authors: Briquet, M.; Neiner, C.; Petit, P.; Leroy, B.; de Batz, B. Bibcode: 2016A&A...587A.126B Altcode: 2016arXiv160104517B
Aims: The main-sequence B-type star ζ Cassiopeiae is known as a N-rich star with a magnetic field discovered with the Musicos spectropolarimeter. We model the magnetic field of the star by means of 82 new spectropolarimetric observations of higher precision to investigate the field strength, topology, and effect.
Methods: We gathered data with the Narval spectropolarimeter installed at Télescope Bernard Lyot (TBL; Pic du Midi, France) and applied the least-squares deconvolution technique to measure the circular polarisation of the light emitted from ζ Cas. We used a dipole oblique rotator model to determine the field configuration by fitting the longitudinal field measurements and by synthesizing the measured Stokes V profiles. We also made use of the Zeeman-Doppler imaging technique to map the stellar surface and to deduce the difference in rotation rate between the pole and equator.
Results: ζ Cas exhibits a polar field strength Bpol of 100-150 G, which is the weakest polar field observed so far in a massive main-sequence star. Surface differential rotation is ruled out by our observations and the field of ζ Cas is strong enough to enforce rigid internal rotation in the radiative zone according to theory. Thus, the star rotates as a solid body in the envelope.
Conclusions: We therefore exclude rotationally induced mixing as the cause of the surface N-enrichment. We discuss that the transport of chemicals from the core to the surface by internal gravity waves is the most plausible explanation for the nitrogen overabundance at the surface of ζ Cas.

Based on observations obtained at the Télescope Bernard Lyot (USR5026) operated by the Observatoire Midi-Pyrénées, Université de Toulouse (Paul Sabatier), Centre National de la Recherche Scientifique (CNRS) of France. Title: The MiMeS survey of magnetism in massive stars: introduction and overview Authors: Wade, G. A.; Neiner, C.; Alecian, E.; Grunhut, J. H.; Petit, V.; Batz, B. de; Bohlender, D. A.; Cohen, D. H.; Henrichs, H. F.; Kochukhov, O.; Landstreet, J. D.; Manset, N.; Martins, F.; Mathis, S.; Oksala, M. E.; Owocki, S. P.; Rivinius, Th.; Shultz, M. E.; Sundqvist, J. O.; Townsend, R. H. D.; ud-Doula, A.; Bouret, J. -C.; Braithwaite, J.; Briquet, M.; Carciofi, A. C.; David-Uraz, A.; Folsom, C. P.; Fullerton, A. W.; Leroy, B.; Marcolino, W. L. F.; Moffat, A. F. J.; Nazé, Y.; Louis, N. St; Aurière, M.; Bagnulo, S.; Bailey, J. D.; Barbá, R. H.; Blazère, A.; Böhm, T.; Catala, C.; Donati, J. -F.; Ferrario, L.; Harrington, D.; Howarth, I. D.; Ignace, R.; Kaper, L.; Lüftinger, T.; Prinja, R.; Vink, J. S.; Weiss, W. W.; Yakunin, I. Bibcode: 2016MNRAS.456....2W Altcode: 2015arXiv151108425W The MiMeS (Magnetism in Massive Stars) project is a large-scale, high-resolution, sensitive spectropolarimetric investigation of the magnetic properties of O- and early B-type stars. Initiated in 2008 and completed in 2013, the project was supported by three Large Program allocations, as well as various programmes initiated by independent principal investigators, and archival resources. Ultimately, over 4800 circularly polarized spectra of 560 O and B stars were collected with the instruments ESPaDOnS (Echelle SpectroPolarimetric Device for the Observation of Stars) at the Canada-France-Hawaii Telescope, Narval at the Télescope Bernard Lyot and HARPSpol at the European Southern Observatory La Silla 3.6 m telescope, making MiMeS by far the largest systematic investigation of massive star magnetism ever undertaken. In this paper, the first in a series reporting the general results of the survey, we introduce the scientific motivation and goals, describe the sample of targets, review the instrumentation and observational techniques used, explain the exposure time calculation designed to provide sensitivity to surface dipole fields above approximately 100 G, discuss the polarimetric performance, stability and uncertainty of the instrumentation, and summarize the previous and forthcoming publications. Title: Search for magnetic fields in particle-accelerating colliding-wind binaries Authors: Neiner, C.; Grunhut, J.; Leroy, B.; De Becker, M.; Rauw, G. Bibcode: 2015A&A...575A..66N Altcode: 2014arXiv1412.5327N Context. Some colliding-wind massive binaries, called particle-accelerating colliding-wind binaries (PACWB), exhibit synchrotron radio emission, which is assumed to be generated by a stellar magnetic field. However, no measurement of magnetic fields in these stars has ever been performed.
Aims: We aim at quantifying the possible stellar magnetic fields present in PACWB to provide constraints for models.
Methods: We gathered 21 high-resolution spectropolarimetric observations of 9 PACWB available in the ESPaDOnS, Narval and HarpsPol archives. We analysed these observations with the least squares deconvolution method. We separated the binary spectral components when possible.
Results: No magnetic signature is detected in any of the 9 PACWB stars and all longitudinal field measurements are compatible with 0 G. We derived the upper field strength of a possible field that could have remained hidden in the noise of the data. While the data are not very constraining for some stars, for several stars we could derive an upper limit of the polar field strength of the order of 200 G.
Conclusions: We can therefore exclude the presence of strong or moderate stellar magnetic fields in PACWB, typical of the ones present in magnetic massive stars. Weak magnetic fields could however be present in these objects. These observational results provide the first quantitative constraints for future models of PACWB.

Based on archival observations obtained at the Télescope Bernard Lyot (USR5026) operated by the Observatoire Midi-Pyrénées, Université de Toulouse (Paul Sabatier), Centre National de la Recherche Scientifique (CNRS) of France, at the Canada-France-Hawaii Telescope (CFHT) operated by the National Research Council of Canada, the Institut National des Sciences de l'Univers of the CNRS of France, and the University of Hawaii, and at the European Southern Observatory (ESO), Chile. Title: γ Pegasi: testing Vega-like magnetic fields in B stars Authors: Neiner, C.; Monin, D.; Leroy, B.; Mathis, S.; Bohlender, D. Bibcode: 2014A&A...562A..59N Altcode: 2013arXiv1312.3521N Context. The bright B pulsator γ Peg shows both p and g modes of β Cep and SPB types. It has also been claimed that it is a magnetic star, while others do not detect any magnetic field.
Aims: We check for the presence of a magnetic field, with the aim to characterise it if it exists, or else provide a firm upper limit of its strength if it is not detected. If γ Peg is magnetic as claimed, it would make an ideal asteroseismic target for testing various theoretical scenarios. If it is very weakly magnetic, it would be the first observation of an extension of Vega-like fields to early B stars. Finally, if it is not magnetic and we can provide a very low upper limit on its non-detected field, it would make an important result for stellar evolution models.
Methods: We acquired high resolution, high signal-to-noise spectropolarimetric Narval data at Telescope Bernard Lyot (TBL). We also gathered existing dimaPol spectropolarimetric data from the Dominion Astrophysical Observatory (DAO) and Musicos spectropolarimetric data from TBL. We analysed the Narval and Musicos observations using the least-squares deconvolution (LSD) technique to derive the longitudinal magnetic field and Zeeman signatures in lines. The longitudinal field strength was also extracted from the Hβ line observed with the DAO. With a Monte Carlo simulation we derived the maximum strength of the field possibly hosted by γ Peg.
Results: We find that no magnetic signatures are visible in the very high quality spectropolarimetric data. The average longitudinal field measured in the Narval data is Bl = -0.1 ± 0.4 G. We derive a very strict upper limit of the dipolar field strength of Bpol ~ 40 G.
Conclusions: We conclude that γ Peg is not magnetic: it hosts neither a strong stable fossil field as observed in a fraction of massive stars nor a very weak Vega-like field. There is therefore no evidence that Vega-like fields exist in B stars, contrary to the predictions by fossil field dichotomy scenarios. These scenarios should thus be revised. Our results also provide strong constraints for stellar evolution models.

Based on observations obtained at the Telescope Bernard Lyot (USR5026) operated by the Observatoire Midi-Pyrénées, Université de Toulouse (Paul Sabatier), Centre National de la Recherche Scientifique of France, and at the Dominion Astrophysical Observatory.Tables 1-3 are available in electronic form at http://www.aanda.org Title: Discovery of a magnetic field in the CoRoT hybrid B-type pulsator HD 43317 Authors: Briquet, M.; Neiner, C.; Leroy, B.; Pápics, P. I.; MiMeS Collaboration Bibcode: 2013A&A...557L..16B Altcode: 2013arXiv1308.4636B Context. A promising way of testing the impact of a magnetic field on internal mixing (core overshooting, internal rotation) in main-sequence B-type stars is to perform asteroseismic studies of a sample of magnetic pulsators.
Aims: The CoRoT satellite revealed that the B3IV star HD 43317 is a hybrid SPB/β Cep-type pulsator that has a wealth of pulsational constraints on which one can perform a seismic modelling, in particular, probing the extent of its convective core and mixing processes. Moreover, indirect indicators of a magnetic field in the star were observed: rotational modulation due to chemical or temperature spots and X-ray emission. Our goal was to directly investigate the field in HD 43317 and, if it is magnetic, to characterise it.
Methods: We collected data with the Narval spectropolarimeter installed at Télescope Bernard Lyot (TBL, Pic du Midi, France) and applied the least-squares deconvolution technique to measure the circular polarisation of the light emitted from HD 43317. We modelled the longitudinal field measurements directly with a dipole.
Results: Zeeman signatures in the Stokes V profiles of HD 43317 are clearly detected and rotationally modulated, which proves that this star exhibits an oblique magnetic field. The modulation with the rotation period deduced from the CoRoT light curve is also confirmed, and we found a field strength at the poles of about 1 kG. Our result must be taken into account in future seismic modelling work of this star.

Based on observations obtained using the Narval spectropolarimeter at the Observatoire du Pic du Midi (France), which is operated by the Institut National des Sciences de l'Univers (INSU). Title: Stochastic gravito-inertial modes discovered by CoRoT in the hot Be star HD 51452 Authors: Neiner, C.; Floquet, M.; Samadi, R.; Espinosa Lara, F.; Frémat, Y.; Mathis, S.; Leroy, B.; de Batz, B.; Rainer, M.; Poretti, E.; Mathias, P.; Guarro Fló, J.; Buil, C.; Ribeiro, J.; Alecian, E.; Andrade, L.; Briquet, M.; Diago, P. D.; Emilio, M.; Fabregat, J.; Gutiérrez-Soto, J.; Hubert, A. -M.; Janot-Pacheco, E.; Martayan, C.; Semaan, T.; Suso, J.; Zorec, J. Bibcode: 2012A&A...546A..47N Altcode: Context. Be stars are rapidly rotating stars with a circumstellar decretion disk. They usually undergo pressure and/or gravity pulsation modes excited by the κ-mechanism, i.e. an effect of the opacity of iron-peak elements in the envelope of the star. In the Milky Way, p-modes are observed in stars that are hotter than or equal to the B3 spectral type, while g-modes are observed at the B2 spectral type and cooler.
Aims: We observed a B0IVe star, HD 51452, with the high-precision, high-cadence photometric CoRoT satellite and high-resolution, ground-based HARPS and SOPHIE spectrographs to study its pulsations in great detail. We also used the lower resolution spectra available in the BeSS database.
Methods: We analyzed the CoRoT and spectroscopic data with several methods: Clean-NG, FreqFind, and a sliding window method. We also analyzed spectral quantities, such as the violet over red (V/R) emission variations, to obtain information about the variation in the circumstellar environment. We calculated a stellar structure model with the ESTER code to test the various interpretation of the results.
Results: We detect 189 frequencies of variations in the CoRoT light curve in the range between 0 and 4.5 c d-1. The main frequencies are also recovered in the spectroscopic data. In particular we find that HD 51452 undergoes gravito-inertial modes that are not in the domain of those excited by the κ-mechanism. We propose that these are stochastic modes excited in the convective zones and that at least some of them are a multiplet of r-modes (i.e. subinertial modes mainly driven by the Coriolis acceleration). Stochastically excited gravito-inertial modes had never been observed in any star, and theory predicted that their very low amplitudes would be undetectable even with CoRoT. We suggest that the amplitudes are enhanced in HD 51452 because of the very rapid stellar rotation. In addition, we find that the amplitude variations of these modes are related to the occurrence of minor outbursts.
Conclusions: Thanks to CoRoT data, we have detected a new kind of pulsations in HD 51452, which are stochastically excited gravito-inertial modes, probably due to its very rapid rotation. These modes are probably also present in other rapidly rotating hot Be stars.

The CoRoT space mission, launched on December 27, 2006, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA (RSSD, and Science Programs), Germany, and Spain. This work uses observations partly made with the HARPS instrument at the 3.6-m ESO telescope (La Silla, Chile) in the framework of the LP182.D-0356, as well as data obtained with Sophie at OHP and from the BeSS database.Table 3 is available in electronic form at http://www.aanda.org Title: Fast calculation of the Lomb-Scargle periodogram using nonequispaced fast Fourier transforms Authors: Leroy, B. Bibcode: 2012A&A...545A..50L Altcode: We present a code for the fast computation of the Lomb-Scargle periodogram that uses nonequispaced fast Fourier transforms (FFTs). The computation time has the classical O(Nlog N) behaviour of FFTs, but is shorter by about one order of magnitude than the "classical" fast algorithm by Press and Rybicki, and is about five times shorter that the best GPU-based implementations of the usual O(N2) algorithm. This performance is achieved without sacrificing accuracy, as revealed by comparing the computations done with our FFT-based algorithm and a naïve one. Title: The Kepler characterization of the variability among A- and F-type stars. I. General overview Authors: Uytterhoeven, K.; Moya, A.; Grigahcène, A.; Guzik, J. A.; Gutiérrez-Soto, J.; Smalley, B.; Handler, G.; Balona, L. A.; Niemczura, E.; Fox Machado, L.; Benatti, S.; Chapellier, E.; Tkachenko, A.; Szabó, R.; Suárez, J. C.; Ripepi, V.; Pascual, J.; Mathias, P.; Martín-Ruíz, S.; Lehmann, H.; Jackiewicz, J.; Hekker, S.; Gruberbauer, M.; García, R. A.; Dumusque, X.; Díaz-Fraile, D.; Bradley, P.; Antoci, V.; Roth, M.; Leroy, B.; Murphy, S. J.; De Cat, P.; Cuypers, J.; Kjeldsen, H.; Christensen-Dalsgaard, J.; Breger, M.; Pigulski, A.; Kiss, L. L.; Still, M.; Thompson, S. E.; van Cleve, J. Bibcode: 2011A&A...534A.125U Altcode: 2011arXiv1107.0335U Context. The Kepler spacecraft is providing time series of photometric data with micromagnitude precision for hundreds of A-F type stars.
Aims: We present a first general characterization of the pulsational behaviour of A-F type stars as observed in the Kepler light curves of a sample of 750 candidate A-F type stars, and observationally investigate the relation between γ Doradus (γ Dor), δ Scuti (δ Sct), and hybrid stars.
Methods: We compile a database of physical parameters for the sample stars from the literature and new ground-based observations. We analyse the Kepler light curve of each star and extract the pulsational frequencies using different frequency analysis methods. We construct two new observables, "energy" and "efficiency", related to the driving energy of the pulsation mode and the convective efficiency of the outer convective zone, respectively.
Results: We propose three main groups to describe the observed variety in pulsating A-F type stars: γ Dor, δ Sct, and hybrid stars. We assign 63% of our sample to one of the three groups, and identify the remaining part as rotationally modulated/active stars, binaries, stars of different spectral type, or stars that show no clear periodic variability. 23% of the stars (171 stars) are hybrid stars, which is a much higher fraction than what has been observed before. We characterize for the first time a large number of A-F type stars (475 stars) in terms of number of detected frequencies, frequency range, and typical pulsation amplitudes. The majority of hybrid stars show frequencies with all kinds of periodicities within the γ Dor and δ Sct range, also between 5 and 10 d-1, which is a challenge for the current models. We find indications for the existence of δ Sct and γ Dor stars beyond the edges of the current observational instability strips. The hybrid stars occupy the entire region within the δ Sct and γ Dor instability strips and beyond. Non-variable stars seem to exist within the instability strips. The location of γ Dor and δ Sct classes in the (Teff, log g)-diagram has been extended. We investigate two newly constructed variables, "efficiency" and "energy", as a means to explore the relation between γ Dor and δ Sct stars.
Conclusions: Our results suggest a revision of the current observational instability strips of δ Sct and γ Dor stars and imply an investigation of pulsation mechanisms to supplement the κ mechanism and convective blocking effect to drive hybrid pulsations. Accurate physical parameters for all stars are needed to confirm these findings. Title: VizieR Online Data Catalog: Variability of A- and F-stars from Kepler (Uytterhoeven+ 2011) Authors: Uytterhoeven, K.; Moya, A.; Grigahcene, A.; Guzik, J. A.; Gutierrez-Soto, J.; Smalley, B.; Handler, G.; Balona, L. A.; Niemczura, E.; Fox Machado, L.; Benatti, S.; Chapellier, E.; Tkachenko, A.; Szabo, R.; Suarez, J. C.; Ripepi, V.; Pascual, J.; Mathias, P.; Martin-Ruiz, S.; Lehmann, H.; Jackiewicz, J.; Hekker, S.; Gruberbauer, M.; Garcia, R. A.; Dumusque, X.; Diaz-Fraile, D.; Bradley, P.; Antoci, V.; Roth, M.; Leroy, B.; Murphy, S. J.; De Cat, P.; Cuypers, J.; Kjeldsen, H.; Christensen-Dalsgaard, J.; Breger, M.; Pigulski, A.; Kiss, L. L.; Still, M.; Thompson, S. E.; van Cleve, J. Bibcode: 2011yCat..35340125U Altcode: 2011yCat..35349125U We compile a database of physical parameters for the sample stars from the literature and new ground-based observations. We analyse the Kepler light curve of each star and extract the pulsational frequencies using different frequency analysis methods. We construct two new observables, 'energy' and 'efficiency', related to the driving energy of the pulsation mode and the convective efficiency of the outer convective zone, respectively.

(5 data files). Title: Kepler observations of the variability in B-type stars Authors: Balona, L. A.; Pigulski, A.; De Cat, P.; Handler, G.; Gutiérrez-Soto, J.; Engelbrecht, C. A.; Frescura, F.; Briquet, M.; Cuypers, J.; Daszyńska-Daszkiewicz, J.; Degroote, P.; Dukes, R. J.; Garcia, R. A.; Green, E. M.; Heber, U.; Kawaler, S. D.; Lehmann, H.; Leroy, B.; Molenda-Żaaowicz, J.; Neiner, C.; Noels, A.; Nuspl, J.; Østensen, R.; Pricopi, D.; Roxburgh, I.; Salmon, S.; Smith, M. A.; Suárez, J. C.; Suran, M.; Szabó, R.; Uytterhoeven, K.; Christensen-Dalsgaard, J.; Kjeldsen, H.; Caldwell, D. A.; Girouard, F. R.; Sanderfer, D. T. Bibcode: 2011MNRAS.413.2403B Altcode: 2011MNRAS.tmp..298B; 2011arXiv1103.0644B The analysis of the light curves of 48 B-type stars observed by Kepler is presented. Among these are 15 pulsating stars, all of which show low frequencies, characteristic of slowly pulsating B (SPB) stars. Seven of these stars also show a few weak, isolated high frequencies and they could be considered as SPB/β Cephei (β Cep) hybrids. In all cases, the frequency spectra are quite different from what is seen from ground-based observations. We suggest that this is because most of the low frequencies are modes of high degree which are predicted to be unstable in models of mid-B stars. We find that there are non-pulsating stars within the β Cep and SPB instability strips. Apart from the pulsating stars, we can identify stars with frequency groupings similar to what is seen in Be stars but which are not Be stars. The origin of the groupings is not clear, but may be related to rotation. We find periodic variations in other stars which we attribute to proximity effects in binary systems or possibly rotational modulation. We find no evidence for pulsating stars between the cool edge of the SPB and the hot edge of the δ Sct instability strips. None of the stars shows the broad features which can be attributed to stochastically excited modes as recently proposed. Among our sample of B stars are two chemically peculiar stars, one of which is a HgMn star showing rotational modulation in the light curve. Title: Asteroseismology of solar-type stars with Kepler I: Data analysis Authors: Karoff, C.; Chaplin, W. J.; Appourchaux, T.; Elsworth, Y.; Garcia, R. A.; Houdek, G.; Metcalfe, T. S.; Molenda-Żakowicz, J.; Monteiro, M. J. P. F. G.; Thompson, M. J.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Kjeldsen, H.; Basu, S.; Bedding, T. R.; Campante, T. L.; Eggenberger, P.; Fletcher, S. T.; Gaulme, P.; Handberg, R.; Hekker, S.; Martic, M.; Mathur, S.; Mosser, B.; Regulo, C.; Roxburgh, I. W.; Salabert, D.; Stello, D.; Verner, G. A.; Belkacem, K.; Biazzo, K.; Cunha, M. S.; Gruberbauer, M.; Guzik, J. A.; Kupka, F.; Leroy, B.; Ludwig, H. -G.; Mathis, S.; Noels, A.; Noyes, R. W.; Roca Cortes, T.; Roth, M.; Sato, K. H.; Schmitt, J.; Suran, M. D.; Trampedach, R.; Uytterhoeven, K.; Ventura, R. Bibcode: 2010AN....331..972K Altcode: 2010arXiv1005.0507K We report on the first asteroseismic analysis of solar-type stars observed by Kepler. Observations of three G-type stars, made at one-minute cadence during the first 33.5 days of science operations, reveal high signal-to-noise solar-like oscillation spectra in all three stars: About 20 modes of oscillation can clearly be distinguished in each star. We discuss the appearance of the oscillation spectra, including the presence of a possible signature of faculae, and the presence of mixed modes in one of the three stars. Title: Photometric variability of the Be star CoRoT-ID 102761769 Authors: Emilio, M.; Andrade, L.; Janot-Pacheco, E.; Baglin, A.; Gutiérrez-Soto, J.; Suárez, J. C.; de Batz, B.; Diago, P.; Fabregat, J.; Floquet, M.; Frémat, Y.; Huat, A. L.; Hubert, A. M.; Espinosa Lara, F.; Leroy, B.; Martayan, C.; Neiner, C.; Semaan, T.; Suso, J. Bibcode: 2010A&A...522A..43E Altcode: 2010arXiv1010.5576E Context. Classical Be stars are rapid rotators of spectral type late O to early A and luminosity class V-III, which exhibit Balmer emission lines and often a near infrared excess originating in an equatorially concentrated circumstellar envelope, both produced by sporadic mass ejection episodes. The causes of the abnormal mass loss (the so-called Be phenomenon) are as yet unknown.
Aims: For the first time, we can now study in detail Be stars outside the Earth's atmosphere with sufficient temporal resolution. We investigate the variability of the Be Star CoRoT-ID 102761769 observed with the CoRoT satellite in the exoplanet field during the initial run.
Methods: One low-resolution spectrum of the star was obtained with the INT telescope at the Observatorio del Roque de los Muchachos. A time series analysis was performed using both cleanest and singular spectrum analysis algorithms to the CoRoT light curve. To identify the pulsation modes of the observed frequencies, we computed a set of models representative of CoRoT-ID 102761769 by varying its main physical parameters inside the uncertainties discussed.
Results: We found two close frequencies related to the star. They are 2.465 c d-1 (28.5 μHz) and 2.441 c d-1 (28.2 μHz). The precision to which those frequencies were found is 0.018 c d-1 (0.2 μHz). The projected stellar rotation was estimated to be 120 km s-1 from the Fourier transform of spectral lines. If CoRoT-ID 102761769 is a typical Galactic Be star it rotates near the critical velocity. The critical rotation frequency of a typical B5-6 star is about 3.5 c d-1 (40.5 μHz), which implies that the above frequencies are really caused by stellar pulsations rather than star's rotation.

The CoRoT space mission was developed and is operated by the French space agency CNES, with participation of ESA's RSSD and Science Programmes, Austria, Belgium, Brazil, Germany, and Spain. 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: The B0.5 IVe CoRoT target HD 49330. II. Spectroscopic ground-based observations Authors: Floquet, M.; Hubert, A. -M.; Huat, A. -L.; Frémat, Y.; Janot-Pacheco, E.; Gutiérrez-Soto, J.; Neiner, C.; de Batz, B.; Leroy, B.; Poretti, E.; Amado, P.; Catala, C.; Rainer, M.; Diaz, D.; Uytterhoeven, K.; Andrade, L.; Diago, P. D.; Emilio, M.; Espinosa Lara, F.; Fabregat, J.; Martayan, C.; Semaan, T.; Suso, J. Bibcode: 2009A&A...506..103F Altcode: Context: We present spectroscopic ground-based observations of the early Be star HD 49330 obtained simultaneously with the CoRoT-LRA1 run just before the burst observed in the CoRoT data.
Aims: Ground-based spectroscopic observations of the early Be star HD 49330 obtained during the precursor phase and just before the start of an outburst allow us to disantangle stellar and circumstellar contributions and identify modes of stellar pulsations in this rapidly rotating star.
Methods: Time series analysis (TSA) is performed on photospheric line profiles of He I and Si III by means of the least squares method.
Results: We find two main frequencies f1 = 11.86 c d-1 and f2 = 16.89 c d-1 which can be associated with high order p-mode pulsations. We also detect a frequency f3 = 1.51 c d-1 which can be associated with a low order g-mode. Moreover we show that the stellar line profile variability changed over the spectroscopic run. These results are in agreement with the results of the CoRoT data analysis, as shown in Huat et al. (2009).
Conclusions: Our study of mid- and short-term spectroscopic variability allows the identification of p- and g-modes in HD 49330. It also allows us to display changes in the line profile variability before the start of an outburst. This brings new constraints for the seimic modelling of this star.

Based on observations made with ESO Telescopes at La Silla Observatory under the ESO Large Programme: LP178.D-0361, and on data collected with the TBL at Pic du Midi Observatory (France). Title: The B0.5IVe CoRoT target HD 49330. I. Photometric analysis from CoRoT data Authors: Huat, A. -L.; Hubert, A. -M.; Baudin, F.; Floquet, M.; Neiner, C.; Frémat, Y.; Gutiérrez-Soto, J.; Andrade, L.; de Batz, B.; Diago, P. D.; Emilio, M.; Espinosa Lara, F.; Fabregat, J.; Janot-Pacheco, E.; Leroy, B.; Martayan, C.; Semaan, T.; Suso, J.; Auvergne, M.; Catala, C.; Michel, E.; Samadi, R. Bibcode: 2009A&A...506...95H Altcode: Context: Be stars undergo outbursts producing a circumstellar disk from the ejected material. The beating of non-radial pulsations has been put forward as a possible mechanism of ejection.
Aims: We analyze the pulsational behavior of the early B0.5IVe star HD 49330 observed during the first CoRoT long run towards the Galactical anticenter (LRA1). This Be star is located close to the lower edge of the β Cephei instability strip in the HR diagram and showed a 0.03 mag outburst during the CoRoT observations. It is thus an ideal case for testing the aforementioned hypothesis.
Methods: We analyze the CoRoT light curve of HD 49330 using Fourier methods and non-linear least square fitting.
Results: In this star, we find pulsation modes typical of β Cep stars (p modes) and SPB stars (g modes) with amplitude variations along the run directly correlated with the outburst. These results provide new clues about the origin of the Be phenomenon as well as strong constraints on the seismic modelling of Be stars.

Tables 3 to 7 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/506/95 Title: Low-amplitude variations detected by CoRoT in the B8IIIe star HD 175869 Authors: Gutiérrez-Soto, J.; Floquet, M.; Samadi, R.; Neiner, C.; Garrido, R.; Fabregat, J.; Frémat, Y.; Diago, P. D.; Huat, A. -L.; Leroy, B.; Emilio, M.; Hubert, A. -M.; Andrade, O. Thizy L.; de Batz, B.; Janot-Pacheco, E.; Espinosa Lara, F.; Martayan, C.; Semaan, T.; Suso, J.; Auvergne, M.; Chaintreuil, S.; Michel, E.; Catala, C. Bibcode: 2009A&A...506..133G Altcode: Context: The origin of the short-term variability in Be stars remains a matter of controversy. Pulsations and rotational modulation are the components of the favored hypothesis.
Aims: We present our analysis of CoRoT data of the B8IIIe star HD 175869 observed during the first short run in the center direction (SRC1).
Methods: We review both the instrumental effects visible in the CoRoT light curve and the analysis methods used by the CoRoT Be team. We applied these methods to the CoRoT light curve of the star HD 175869. A search for line-profile variations in the spectroscopic data was also performed. We also searched for a magnetic field, by applying the LSD technique to spectropolarimetric data.
Results: The light curve exhibits low-amplitude variations of the order of 300 μmag with a double wave shape. A frequency within the range determined for the rotational frequency and 6 of its harmonics are detected. The main frequency and its first harmonic exhibit amplitude variations of a few days. Other significant frequencies of low-amplitude from 25 to a few μmag are also found. The analysis of line profiles from ground-based spectroscopic data does not detect any variation. In addition, no Zeeman signature was found.
Conclusions: Inhomogeneities caused by stellar activity in or just above the photosphere are proposed to produce the photometric variability detected by CoRoT in the Be star HD 175869. The hypothesis that non-radial pulsations are the origin of these variations cannot be excluded. Title: Pulsations in the late-type Be star HD 50 209 detected by CoRoT Authors: Diago, P. D.; Gutiérrez-Soto, J.; Auvergne, M.; Fabregat, J.; Hubert, A. -M.; Floquet, M.; Frémat, Y.; Garrido, R.; Andrade, L.; de Batz, B.; Emilio, M.; Espinosa Lara, F.; Huat, A. -L.; Janot-Pacheco, E.; Leroy, B.; Martayan, C.; Neiner, C.; Semaan, T.; Suso, J.; Catala, C.; Poretti, E.; Rainer, M.; Uytterhoeven, K.; Michel, E.; Samadi, R. Bibcode: 2009A&A...506..125D Altcode: 2009arXiv0909.4524D Context: The presence of pulsations in late-type Be stars is still a matter of controversy. It constitutes an important issue to establish the relationship between non-radial pulsations and the mass-loss mechanism in Be stars.
Aims: To contribute to this discussion, we analyse the photometric time series of the B8IVe star HD 50 209 observed by the CoRoT mission in the seismology field.
Methods: We use standard Fourier techniques and linear and non-linear least squares fitting methods to analyse the CoRoT light curve. In addition, we applied detailed modelling of high-resolution spectra to obtain the fundamental physical parameters of the star.
Results: We have found four frequencies which correspond to gravity modes with azimuthal order m=0,-1,-2,-3 with the same pulsational frequency in the co-rotating frame. We also found a rotational period with a frequency of 0.679 cd-1 (7.754 μHz).
Conclusions: HD 50 209 is a pulsating Be star as expected from its position in the HR diagram, close to the SPB instability strip.

Based on observations made with the CoRoT satellite, with FEROS at the 2.2 m telescope of the La Silla Observatory under the ESO Large Programme LP178.D-0361 and with Narval at the Télescope Bernard Lyot of the Pic du Midi Observatory. Current address: Valencian International University (VIU), José Pradas Gallen s/n, 12006 Castellón, Spain. Current address: Laboratoire AIM, CEA/DSM-CNRS-Université Paris Diderot; CEA, IRFU, SAp, centre de Saclay, 91191 Gif-sur-Yvette, France. Title: The pulsations of the B5IVe star HD 181231 observed with CoRoT and ground-based spectroscopy Authors: Neiner, C.; Gutiérrez-Soto, J.; Baudin, F.; de Batz, B.; Frémat, Y.; Huat, A. L.; Floquet, M.; Hubert, A. -M.; Leroy, B.; Diago, P. D.; Poretti, E.; Carrier, F.; Rainer, M.; Catala, C.; Thizy, O.; Buil, C.; Ribeiro, J.; Andrade, L.; Emilio, M.; Espinosa Lara, F.; Fabregat, J.; Janot-Pacheco, E.; Martayan, C.; Semaan, T.; Suso, J.; Baglin, A.; Michel, E.; Samadi, R. Bibcode: 2009A&A...506..143N Altcode: Context: HD 181231 is a B5IVe star, which has been observed with the CoRoT satellite during ~5 consecutive months and simultaneously from the ground in spectroscopy and spectropolarimetry.
Aims: By analysing these data, we aim to detect and characterize as many pulsation frequencies as possible, to search for the presence of beating effects possibly at the origin of the Be phenomenon. Our results will also provide a basis for seismic modelling.
Methods: The fundamental parameters of the star are determined from spectral fitting and from the study of the circumstellar emission. The CoRoT photometric data and ground-based spectroscopy are analysed using several Fourier techniques: Clean-ng, Pasper, and Tisaft, as well as a time-frequency technique. A search for a magnetic field is performed by applying the LSD technique to the spectropolarimetric data.
Results: We find that HD 181231 is a B5IVe star seen with an inclination of ~45 degrees. No magnetic field is detected in its photosphere. We detect at least 10 independent significant frequencies of variations among the 54 detected frequencies, interpreted in terms of non-radial pulsation modes and rotation. Two longer-term variations are also detected: one at ~14 days resulting from a beating effect between the two main frequencies of short-term variations, the other at ~116 days due either to a beating of frequencies or to a zonal pulsation mode.
Conclusions: Our analysis of the CoRoT light curve and ground-based spectroscopic data of HD 181231 has led to the determination of the fundamental and pulsational parameters of the star, including beating effects. This will allow a precise seismic modelling of this star.

Based on observations obtained with the CoRoT satellite, with FEROS at the 2.2 m télescope of the La Silla Observatory under the ESO Large Programme LP178.D-0361, with Narval at the Télescope Bernard Lyot of the Pic du Midi Observatory, and collected from the BeSS database. Table 5 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/506/143 Title: VizieR Online Data Catalog: Pulsations of HD 181231 (Neiner+, 2009) Authors: Neiner, C.; Gutierrez-Soto, J.; Baudin, F.; de Batz, B.; Fremat, Y.; Huat, A. -L.; Floquet, M.; Hubert, A. -M.; Leroy, B.; Diago, P. D.; Poretti, E.; Carrier, F.; Rainer, M.; Catala, C.; Thizy, O.; Buil, C.; Ribeiro, J.; Andrade, L.; Emilio, M.; Espinosa, F. Lara; Fabregat, J.; Janot-Pacheco, E.; Martayan, C.; Semaan, T.; Suso, J.; Baglin, A.; Michel, E.; Samadi, R. Bibcode: 2009yCat..35060143N Altcode: Frequencies (in c/d and microHz) detected in the CoRoT data of HD181231 with the TiSAFT, Clean-NG, and Pasper methods. The minimum detectable frequency is 1/T=0.0064 c/d, i.e., 0.075microHz, where T is the length of the run. The error bar of the frequencies is Delta_f=1/(4T)=0.0016 c/d, i.e., 0.019 microHz. The amplitudes and phases calculated with Amphi for each of the three sets of frequencies are reported in Cols. 5 and 6 together with their error bars. The last column gives our interpretation of each frequency.

(1 data file). Title: VizieR Online Data Catalog: Fourier analysis of HD 49330 CoRoT light curve (Huat+, 2009) Authors: Huat, A. -L.; Hubert, A. -M.; Baudin, F.; Floquet, M.; Neiner, C.; Fremat, Y.; Gutierrez-Soto, J.; Andrade, L.; de Batz, B.; Diago, P. D.; Emilio, M.; Espinosa, F. Lara; Fabregat, J.; Janot-Pacheco, E.; Leroy, B.; Martayan, C.; Semaan, T.; Suso, J.; Auvergne, M.; Catala, C.; Michel, E.; Samadi, R. Bibcode: 2009yCat..35060095H Altcode: This work analyses the high precision photometric light curve obtained for the CoRoT target HD49330 (B0.5 IVe) which was observed during 136.886 days with a sample of 32s. During the CoRoT run the star underwent an outburst often observed in hot Be star. The CoRoT light curve was analysed using Fourier methods and non-linear least square fitting.

(5 data files). Title: Low-amplitude variations detected by CoRoT in the late type Be star HD 175869 Authors: Gutiérrez-Soto, J.; Floquet, M.; Neiner, C.; Hubert, A. -M.; Frémat, Y.; Andrade, L.; de Batz, B.; Diago, P. D.; Emilio, M.; Fabregat, J.; Facanha, W.; Huat, A. -L.; Janot-Pacheco, E.; Leroy, B.; Martayan, C.; Suso, J.; Garrido, R. Bibcode: 2009CoAst.158..208G Altcode: We present the analysis of the CoRoT data of the B8IIIe star HD 175869 observed during a short run (27.3 days). The light curve shows low-amplitude variations of the order of 0.3 mmag. A frequency within the range determined for the rotational frequency and its 5 harmonics are detected. Other significant frequencies with a low amplitude of a few ppm are also found. The analysis of line profiles from ground-based spectroscopic data does not show any variation. Title: Application of the TiSAFT code (Time Series Analysis with Fisher's Test) Authors: Huat, A. -L.; Leroy, B.; Diago, P. D. Bibcode: 2009CoAst.158..211H Altcode: A new code for extracting frequencies, amplitudes and phases in a time series has been developed for the CoRoT data analysis: TiSAFT (Time Series Analysis with Fisher's Test of significance). We provide an application of the TiSAFT code on a simulated β Cephei light curve and on CoRoT data of a Be star, as well as a comparison with other codes already used in the CoRoT Be team. Title: Preliminary results on the pulsations of Be stars with CoRoT Authors: Neiner, C.; Gutiérrez-Soto, J.; Floquet, M.; Huat, A. -L.; Hubert, A. -M.; de Batz, B.; Leroy, B.; Frémat, Y.; Andrade, L.; Diago, P. D.; Emilio, M.; Fabregat, J.; Janot-Pacheco, E.; Martayan, C.; Semaan, T.; Suso, J. Bibcode: 2009CoAst.158..319N Altcode: We present preliminary results of the study of pulsations of Be stars from CoRoT observations. CoRoT detected many pulsation frequencies in all observed Be stars, usually interpreted in terms of g-modes but sometimes also corresponding to p-modes. Even in late Be stars, for which the detection of pulsation frequencies is very difficult from the ground, because of their very low amplitude, the quality and precision of the CoRoT data allows us to detect many frequencies. Seismic models have not yet been calculated but the calculations are ongoing. Title: First results on the Be stars observed with the CoRoT satellite Authors: Gutierrez-Soto, J.; Neiner, C.; Hubert, A. -M.; Floquet, M.; Huat, A. -L.; Diago, P. D.; Fabregat, J.; Leroy, B.; De Batz, B.; Andrade, L.; Emilio, M.; Facanha, W.; Fremat, Y.; Janot-Pacheco, E.; Martayan, C.; Suso, J. Bibcode: 2008CoAst.157...70G Altcode: In this paper we present an overview of the analysis of some of the Be stars observed with the CoRoT satellite up to this date. Be stars are very fast-rotating B-type stars which may pulsate as β Cephei or SPB stars. CoRoT has already observed 5 bright Be stars in the seismology fields and several tens of fainter ones in the exoplanet fields with an unprecedented quality and with a time duration from 20 to 150 days. Multiple frequencies are detected in the majority of the stars. Pulsations, outbursts, beating phenomenon, possible transient modes, rotation, amplitude variability, etc. have been found in their light curves. In order to complement this study, ground-based spectroscopic data have also been analysed for the stars located in the seismology fields. Title: The pulsations of the B5IVe star HD181231 revealed by CoRoT Authors: Neiner, C.; Gutierrez-Soto, J.; Fremat, Y.; Floquet, M.; Hubert, A. -M.; Leroy, B.; de Batz, B.; Huat, A. -L.; Martayan, C.; Andrade, L.; Emilio, M.; Fabregat, J.; Facanha, W.; Janot-Pacheco, E.; Suso, J. Bibcode: 2008CoAst.157..349N Altcode: We present the first results of the analysis of the light curve of the B5IVe star HD 181231 obtained during a long run (5 months) of the CoRoT mission. The light curve shows clear pulsations and even beating effects. Several frequencies are detected. Ground-based spec- troscopic data have also been analyzed and help to determine the rotation frequency and identify pulsation modes. Title: First asteroseismic results from CoRoT Authors: Michel, E.; Baglin, A.; Weiss, W. W.; Auvergne, M.; Catala, C.; Aerts, C.; Appourchaux, T.; Barban, C.; Baudin, F.; Briquet, M.; Carrier, F.; Degroote, P.; De Ridder, J.; Garcia, R. A.; Garrido, R.; Gutiérrez-Soto, J.; Kallinger, T.; Lefevre, L.; Neiner, C.; Poretti, E.; Samadi, R.; Sarro, L.; Alecian, G.; Andrade, L.; Ballot, J.; Benomar, O.; Berthomieu, G.; Boumier, P.; Charpinet, S.; de Batz, B.; Deheuvels, S.; Dupret, M. -A.; Emilio, M.; Fabregat, J.; Facanha, W.; Floquet, M.; Frémat, Y.; Fridlund, M.; Goupil, M. -J.; Grotsch-Noels, A.; Handler, G.; Huat, A. -L.; Hubert, A. -M.; Janot-Pacheco, E.; Kjeldsen, H.; Lebreton, Y.; Leroy, B.; Martayan, C.; Mathias, P.; Miglio, A.; Montalban, J.; Monteiro, M. J. P. F. G.; Mosser, B.; Provost, J; Regulo, C.; Renan de Medeiros, J.; Ribas, I.; Roca Cortés, T.; Roxburgh, I.; Suso, J.; Thoul, A.; Toutain, T.; Tiphene, D.; Turck-Chieze, S.; Vauclair, S.; Vauclair, G.; Zwintz, K. Bibcode: 2008CoAst.156...73M Altcode: About one year after the end of the first observational run and six months after the first CoRoT data delivery, we comment the data exploitation progress for different types of stars. We consider first results to illustrate how these data of unprecedented quality shed a new light on the field of stellar seismology. Title: First results on Be stars with CoRoT Authors: Gutiérrez-Soto, J.; Neiner, C.; Hubert, A. -M.; Floquet, M.; Huat, A. -L.; Diago, P. D.; Fabregat, J.; Leroy, B.; de Batz, B.; Andrade, L.; Emilio, M.; Facanha, W.; Frémat, Y.; Janot-Pacheco, E.; Martayan, M.; Suso, J.; Garrido, R. Bibcode: 2008sf2a.conf..475G Altcode: In this paper we present an overview of the analysis of some of the Be stars observed with the CoRoT satellite up to this date. Be stars are very fast-rotating B-type stars which may pulsate as β Cephei or SPB stars. CoRoT has already observed 5 bright Be stars in the seismology fields and several tens of fainter ones in the exoplanet fields with an unprecedented quality and with a time duration from 20 to 150 days. Multiple frequencies are detected in the majority of the stars. Pulsations, outbursts, beating phenomenon, rotation, amplitude variability, etc. have been found in their light curves. In order to complement this study, ground-based spectroscopic data have also been analysed for the stars located in the seismology fields. Title: The Gaia satellite: a tool for Emission Line Stars and Hot Stars Authors: Martayan, C.; Frémat, Y.; Blomme, R.; Jonckheere, A.; Borges, M.; de Batz, B.; Leroy, B.; Sordo, R.; Bouret, J. -C.; Martins, F.; Zorec, J.; Neiner, C.; Nazé, Y.; Alecian, E.; Floquet, M.; Hubert, A. -M.; Briot, D.; Miroshnichenko, A.; Kolka, I.; Stee, P.; Lanz, T.; Meynet, G. Bibcode: 2008sf2a.conf..499M Altcode: 2008arXiv0809.4417M The Gaia satellite will be launched at the end of 2011. It will observe at least 1 billion stars, and among them several million emission line stars and hot stars. Gaia will provide parallaxes for each star and spectra for stars till V magnitude equal to 17. After a general description of Gaia, we present the codes and methods, which are currently developed by our team. They will provide automatically the astrophysical parameters and spectral classification for the hot and emission line stars in the Milky Way and other close local group galaxies such as the Magellanic Clouds. Title: New Methods for the Simulation of Ablative Thermal Protections Authors: Nguyen-Bui, N. T. H.; Duffa, G.; Dubroca, B.; Leroy, B. Bibcode: 2006ESASP.631E..13N Altcode: 2006tpsh.confE..13N No abstract at ADS Title: Inversion of line profiles using principal component analysis: some practical guidelines Authors: Leroy, B. Bibcode: 2003EAS.....9..117L Altcode: Modern spectro-polarimeters produce huge amounts of data, and the

computing time needed to achieve data inversion is then becoming an

important bottleneck for the modelling activity. Recently, an

alternative to the traditional non-linear least squares technique

has been proposed; it relies on an old technique in multivariate

analysis, principal component analysis (PCA), and proves to be

much faster than traditional techniques (a gain of two

orders of magnitude in computation time is not unusual). We will

briefly recall this technique and discuss some means of making it

still more robust. Title: Lockheed Martin Team's Next Generation Space Telescope (NGST) Reference Architecture Authors: Martin, F.; Lesyna, L.; LeRoy, B.; Menzel, M.; Andersen, G.; Hyatt, B.; Triebes, K.; Rudiger, C.; Stier, M.; Cox, C.; Delp, C.; Hachkowski, R.; Hardman, G.; Keane, M.; MacFarlane, M.; Mordino, A.; Krim, M. Bibcode: 2000ASPC..207...46M Altcode: 2000ngst.conf...46M No abstract at ADS Title: Improvements in Ablation Predictions for Reentry-Vehicles Nosetip Authors: Couzi, J.; de Winne, J.; Leroy, B. Bibcode: 1999ESASP.426..493C Altcode: 1999asv..conf..493C No abstract at ADS Title: Zeeman splitting in interstellar molecules. II. The ethynyl radical Authors: Bel, N.; Leroy, B. Bibcode: 1998A&A...335.1025B Altcode: The Zeeman splitting that a longitudinal magnetic field would produce on the ethynyl radical is calculated for the transitions typical of those observed in the interstellar clouds. It turns out that the ubiquitous CCH radical adds to the list of the few interstellar molecules that could be used to determine magnetic fields in molecular clouds. Title: Electrical properties of the gas within molecular clouds. Authors: Bel, N.; Leroy, B. Bibcode: 1996A&A...305..598B Altcode: The electrical properties of the matter within a molecular cloud are examined. It is verified that, whilst the MHD approximation is still valid, the dominating presence of neutrals is the source of a very large anisotropy of the electrical conductivity; indeed, the latter differs in the directions parallel and perpendicular to the magnetic field by many orders of magnitude. The implication of this result for the dissipative processes (e.g., wave dissipation) cannot be underestimated. This anisotropy prevails during a large part of the evolution of a cloud. Title: The dynamics of the solar convective zone by means of magnetic tracers Authors: Collin, B.; Nesme-Ribes, E.; Leroy, B.; Meunier, N.; Sokoloff, D. Bibcode: 1995CRASB.321..111C Altcode: 1995CRASM.321..111C The rotation of the sun's convective zone can be studied by using the motions of magnetic features observed in the solar atmosphere but deeply rooted. It becomes possible to assign a depth of anchorage to these magnetic tracers, by helioseismology, which probes solar rotation layer by layer. Title: Presumptive evidence for a low value of the total ozone content above Antarctica in September, 1958 Authors: Rigaud, P.; Leroy, B. Bibcode: 1990AnGeo...8..791R Altcode: No abstract at ADS Title: Observability of the Magnetic Field in Molecular Clouds Authors: Bel, N.; Leroy, B. Bibcode: 1990IAUS..140..304B Altcode: No abstract at ADS Title: Zeeman splitting in interstellar molecules. Authors: Bel, N.; Leroy, B. Bibcode: 1989A&A...224..206B Altcode: The Zeeman splitting due to a longitudinal magnetic field on some transitions of diatomic molecules observed in the interstellar clouds are calculated. Only CN and SO exhibit effects comparable to that of OH. Their observability in the mm range is discussed. In the same wavelength range, O2 would exhibit Zeeman effects even larger than that of OH, but must be observed from space radiotelescopes. Title: Visible absorption cross-sections of NO2 at 298 K and 235 K Authors: Leroy, B.; Rigaud, P.; Hicks, E. Bibcode: 1987AnGeo...5..247L Altcode: The absorption cross-sections of NO2 are measured between 426.8 nm and 449.9 nm in increments of 0.1 nm at temperatures of 298 K and 235 K. The present results are applied to the C.M.S. (Composes Minoritaires Stratospheriques) spectrometer of the Geneva Observatory. Title: Résolution analytique approchée des équations différentielles (ordinaires et aux dérivées partielles). Authors: Leroy, B. Bibcode: 1986mma..conf...33L Altcode: No abstract at ADS Title: Caractère quasi-universel des équations asymptotiques. Authors: Leroy, B. Bibcode: 1986mma..conf..439L Altcode: No abstract at ADS Title: On the derivation of the energy flux of linear magnetohydrodynamic waves Authors: Leroy, B. Bibcode: 1985GApFD..32..123L Altcode: New light is shed on the derivation of the energy flux of the linear MHD waves. It is shown that, according to a suggestion of Lighthill, the usual perturbation procedure, which starts from the general expression for the energy flux, need not be supplemented by an averaging procedure. As a result, it is shown that to second order in the wave amplitude, a quantity identifiable as the wave energy flux is conserved. Some of the subtleties inherent in the derivation of the perturbation energy equation are discussed. Title: Phase Mixing of Propagating Alfven Waves Authors: Nocera, L.; Leroy, B.; Priest, E. R. Bibcode: 1985IAUS..107..365N Altcode: Among MHD waves, Alfvén waves have been proved to be the best candidates to reach the solar corona and, eventually, to be responsible for the heating of this outer part of the solar atmosphere. The problem concerning the mechanism able to transform the energy stored in the waves into heat is considered. Title: Phase mixing of propagating Alfven waves Authors: Nocera, L.; Priest, E. R.; Leroy, B. Bibcode: 1984A&A...133..387N Altcode: The fundamental wave solution found by Heyvaerts and Priest (1983) for the propagation and damping of shear Alfven waves in an inhomogeneous medium is checked against their assumptions, and a range of self-consistency is provided. By analyzing wave behavior outside this range, novel wave propagation properties are discovered. In the limit of weak damping, a uniformly valid solution is obtained by the method of multiple scales. For long wavelengths, the diffusion of energy in the direction transverse to the wave propagation is found to be important, and leads to weaker damping laws than those found by Heyvaerts and Priest. Title: Introduction à la magnétohydrodynamique. Authors: Leroy, B. Bibcode: 1984cms..conf..123L Altcode: No abstract at ADS Title: Magnetoacoustic Gravity Waves and the Heating of the Solar Corona Authors: Leroy, B. Bibcode: 1984apoa.conf..326L Altcode: No abstract at ADS Title: Spectres d'absorption dans le proche ultraviolet de CS2 et SO2 entre 200 et 300K Authors: Leroy, B.; Rigaud, P.; Jourdain, J. L.; Le Bras, G. Bibcode: 1983M&P....29..177L Altcode: Spectres d'absorption dans le proche ultraviolet de CS2 et SO2 entre 200 et 300K Title: Propagation of Alfven waves in an isothermal atmosphere when the displacement current is not neglected Authors: Leroy, B. Bibcode: 1983A&A...125..371L Altcode: If the solar atmosphere is modelled by a medium with a (possibly piece-wise) exponentially decreasing density, permeated by a uniform magnetic field, for MHD waves with a period ranging between a few seconds and several hours the WKBJ approximation is nowhere valid. Consequently, the concept of travelling wave is no longer meaningful and difficulties arise concerning the boundary condition that there be no incoming wave from infinity. In the past, these have been circumvented by confining arbitrarily the inhomogeneous medium to a region of finite extension. In the present paper the author proposes an alternative solution devoid of this free parameter; it simply consists in not discarding the displacement current in Maxwell's equations. Title: Notions générales d'hydrodynamique. Authors: Leroy, B. Bibcode: 1983ihaa.conf....3L Altcode: Contents: Introduction. Equations fondamentales. Similitude dynamique - analyse dimensionnelle. Approximation de Boussinesq - critères de similitude de la convection. Linéarisation - instabilité. Title: Propagation of Waves in an Atmosphere in the Presence of a Magnetic Field - Part Six - Application of Magneto-Acoustic Mode Theory to the Solar Atmosphere Authors: Schwartz, S. J.; Leroy, B. Bibcode: 1982A&A...112...93S Altcode: The theory of magneto-acoustic-gravity oscillations in an exponential atmosphere permeated by a uniform vertical magnetic field, presented by us in a companion paper, is applied to the solar atmosphere. Numerical parameters typical of both sunspots and coronal hole regions are used in our investigations over a wide frequency range of the energy flux carried by such oscillations from the photosphere to the corona. We conclude that the combined effects of stratification, partially transverse propagation and the transition region make it unlikely that such modes dominate coronal energetics. Title: Propagation of waves in an atmosphere in the presence of a magnetic field. V - The theory of magneto-acoustic-gravity oscillations. VI - Application of magneto-acoustic-gravity mode theory to the solar atmosphere Authors: Leroy, B.; Schwartz, S. J. Bibcode: 1982A&A...112...84L Altcode: The study concerns the oscillations and associated energy flux in a horizontally stratified medium permeated by a uniform vertical magnetic field parallel to a uniform gravitational field. Particular attention is given to the obvious applications to sunspots and the corona. In addition to the Alfven mode, the inhomogeneous analogs of the fast and slow MHD waves which propagate in a homogeneous medium are found. The boundary conditions and energy flux calculations that are appropriate for these modes are discussed, as are some general considerations of the series solutions themselves. The theory is then applied to the solar atmosphere. Numerical parameters typical of both sunspots and coronal hole regions are used in the investigations over a wide frequency range of the energy flux carried by such oscillations from the photosphere to the corona. It is concluded that the combined effects of stratification, partially transverse propagation, and the transition region make it unlikely that such modes dominate coronal energetics. Title: Coronal oscillations - Energy transport in the sun by magneto-atmospheric modes Authors: Leroy, B. Bibcode: 1982PhDT.........1L Altcode: Errors are demonstrated to exist in an eikonal approximation of the wave propagation in the solar atmosphere, and possible models for wave heating of the corona are considered. Consideration is given to data from the ATM instruments on board Skylab, from the OSO series satellites, and to studies of other stellar coronas with the IUE and Einstein Observatory. It is shown that Alfven waves propagating from the convection zone are not strong enough to heat the solar corona to the observed levels, which are actually hotter than those in the photosphere, although the corona has a less dense composition. A zone is argued to exist where magnetogravitosonic waves emerge in relatively stable condition, and have been detected in the solar wind. A linear analysis is presented to identify the region of origin of the upcoming waves, showing that slow vertical oscillations emerge above sunspots while slow magnetohydrodynamic waves do not. Title: Propagation of waves in an atmosphere in the presence of a magnetic field. IV - Alfven waves in sunspot umbrae Authors: Bel, N.; Leroy, B. Bibcode: 1981A&A...104..203B Altcode: The propagation of Alfven waves in a sunspot is studied without the aid of the eikonal approximation. It is found that the outgoing energy flux density reaching the corona is less than 10 to the -5 of the input energy flux density. This shows clearly that the cooling of sunspots by ascending Alfven waves is not possible. In the study, special attention is given to the transmittance of the atmosphere. Title: Propagation of waves in an atmosphere in the presence of a magnetic field. III - Alfven waves in the solar atmosphere Authors: Leroy, B. Bibcode: 1981A&A....97..245L Altcode: The propagation of Alfven waves is treated within the framework of a realistic model of the solar atmosphere without recourse to the eikonal approximation. The very low value of the transmittance (less than 1 percent) indicates that Alfven waves observed in the interplanetary medium have not been generated in the sun's convection zone. This conclusion is supported by Pioneer 6 data. Title: Propagation of waves in an atmosphere in the presence of a magnetic field. II - The reflection of Alfven waves Authors: Leroy, B. Bibcode: 1980A&A....91..136L Altcode: The propagation of linear Alfven waves in an isothermal atmosphere is investigated without the use of the WKBJ approximation. Wave reflection induced by the density gradient is studied in detail, and special emphasis is placed on the coupled-modes representation. As an example, attention is given to the reflectance and transmittance of a slab of isothermal atmosphere with respect to Alfven waves. Title: Determination of the total content of atmospheric nitrogen dioxide from ground-based measurements of stellar spectra Authors: Leroy, B.; Hicks, E.; Vassy, A. Bibcode: 1980AnG....36..205L Altcode: From the experimental work of A. and E. Vassy (1937) on atmospheric absorption which was carried out in Morocco, the total atmospheric content of nitrogen dioxide was determined. The results obtained from stellar spectra, taken from the ground, vary according to the season and outline a night decay of NO2. The average value of the total atmospheric content of NO2 ranges from 5 x 10 to the 16th to 1 x 10 to the 17th molecules/sq cm. Title: Some Comments on the Propagation of Alfven Waves in an Atmosphere Authors: Leroy, B. Bibcode: 1980jfss.conf..251L Altcode: No abstract at ADS Title: Reflexion and Transmission of Alfven Waves in an Atmosphere Authors: Bel, N.; Leroy, B. Bibcode: 1980IAUS...91..131B Altcode: No abstract at ADS Title: Propagation of waves in an atmosphere in the presence of a magnetic field. I. The method. Authors: Leroy, B.; Bel, N. Bibcode: 1979A&A....78..129L Altcode: A method is developed for studying MHD-wave propagation in an isothermal atmosphere permeated by a uniform magnetic field. The hydrodynamic Lagrangian for an infinitely conducting and isothermal atmosphere permeated by an arbitrary magnetic field is examined, the Euler-Lagrange equations are obtained, and some physical insight into the terms involved is given. Whitman's (1965) averaged Lagrangian method is reviewed and applied to magnetoacoustic gravity waves propagating in an isothermal atmosphere permeated by a uniform magnetic field arbitrarily oriented with respect to the (constant) gravity field. The general equations of motion are derived in the linear approximation, and an analytical method is outlined for solving these equations. Title: A four-filter photometer for the measurement of total ozone in the atmosphere. Authors: Leroy, B. Bibcode: 1977JApMe..16.1082L Altcode: The paper examines the design (optical and electronic), operating principle and calibration of a photometer which, using four interference filters and a photocell, is designed for the measurement of total ozone in the atmosphere from solar light scattered by the zenith sky. In a 1974 field test the four-filter photometer was compared to other instruments, particularly the Dobson spectrophotometer. It was determined that to avoid errors, the photometer data should be supplemented with a study of the effects of cloud cover, bandwidth and aerosols on total ozone measurements. Title: Etude statistique des relations entre la radiation X solaire, les renforcements soudains d'atmosphériques et les plages d'activité solaire Authors: Leroy, B. Bibcode: 1977C&T....93..215L Altcode: A statistical study correlating low-frequency electromagnetic wave propagation in the ionosphere, solar X-ray radiation and ranges of solar activity is reported. The level of solar X-ray radiation is found to correlate with the energetics of the electromagnetic wave propagation; a background level of Sudden Enhancement of Atmospherics (SEA) and a higher degree of enhancement are distinguished. Solar activity ranges determined from Solar Geophysical Data are also correlated to the SEA levels. Title: Analytical Study of Magnetoacoustic Gravity Waves Authors: Bel, N.; Leroy, B. Bibcode: 1977A&A....55..239B Altcode: Summary. An analytical study of magneto-acoustic gravity waves propagating in an isothermal atmosphere along the gravity field has been done; we obtain the equation giving the cut-off frequency and we establish the conditions for the existence of a cross-over in the dispersion equation. Key words: waves linear coupling magnetic field gravity solar atmosphere Title: On the Possibility of Nucleosynthesis in Any Matter-Antimatter Symmetric Cosmology Authors: Combes, F.; Fassi-Fehri, O.; Leroy, B. Bibcode: 1975Ap&SS..37..151C Altcode: In any matter-antimatter symmetric cosmology the primeval nucleosynthesis imposes a typical size of a region of matter (antimatter) much larger than the diffusion length of neutrons. Observational results on the abundances of cosmic deuterium and helium are used to evaluate how large it has to be. As a result we find that a minimal sizeL 1∼1.5×108 cm at the temperatureT=1 MeV is compatible with the standard abundances of primeval helium and deuterium. Title: Nucleosynthesis in a Symmetrical Universe Authors: Combes, F.; Fassi-Fehri, O.; Leroy, B. Bibcode: 1975hea..conf..155C Altcode: No abstract at ADS Title: Nucleosynthesis and matter-antimatter cosmologies Authors: Combes, F.; Fassi-Fehri, O.; Leroy, B. Bibcode: 1975Natur.253...25C Altcode: IF light elements are of cosmological origin, then a given cosmological model should be able to reproduce the observed abundances1. Symmetric matter-antimatter cosmologies2-4 do not stand up to this test too well, and encounter problems whose basis is the annihilation process itself. Title: The Deuterium Puzzle in the Symmetric Universe Authors: Leroy, B.; Nicolle, J. P.; Schatzman, E. Bibcode: 1973NASSP.339..351L Altcode: 1973gra..conf..351L No abstract at ADS