Mixed modes in red-giant stars observed with CoRoT
English
Mosser, B.[LESIA, CNRS, Université Pierre et Marie Curie, Université Denis Diderot, Observatoire de Paris, 92195, Meudon Cedex, France]
Barban, C.[LESIA, CNRS, Université Pierre et Marie Curie, Université Denis Diderot, Observatoire de Paris, 92195, Meudon Cedex, France]
Montalban Iglesias, Josefa[Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie]
Beck, P. G.[Instituut voor Sterrenkunde, K. U. Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium]
Miglio, Andrea[Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie]
Belkacem, K.[Institut d'Astrophysique Spatiale, UMR 8617, Université Paris XI, Bâtiment 121, 91405, Orsay Cedex, France; LESIA, CNRS, Université Pierre et Marie Curie, Université Denis Diderot, Observatoire de Paris, 92195, Meudon Cedex, France]
Goupil, M. J.[LESIA, CNRS, Université Pierre et Marie Curie, Université Denis Diderot, Observatoire de Paris, 92195, Meudon Cedex, France]
Hekker, S.[School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK; Astronomical Institute "Anton Pannekoek", University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands]
De Ridder, J.[Instituut voor Sterrenkunde, K. U. Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium]
Dupret, Marc-Antoine[Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie]
Elsworth, Y.[School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK]
Noels-Grötsch, Arlette[Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Département d'astrophys., géophysique et océanographie (AGO) >]
Baudin, F.[Institut d'Astrophysique Spatiale, UMR 8617, Université Paris XI, Bâtiment 121, 91405, Orsay Cedex, France]
[en] Context. The CoRoT mission has provided thousands of red-giant light curves. The analysis of their solar-like oscillations allows us to characterize their stellar properties. <BR /> Aims: Up to now, the global seismic parameters of the pressure modes have been unable to distinguish red-clump giants from members of the red-giant branch. As recently done with Kepler red giants, we intend to analyze and use the so-called mixed modes to determine the evolutionary status of the red giants observed with CoRoT. We also aim at deriving different seismic characteristics depending on evolution. <BR /> Methods: The complete identification of the pressure eigenmodes provided by the red-giant universal oscillation pattern allows us to aim at the mixed modes surrounding the ℓ = 1 expected eigenfrequencies. A dedicated method based on the envelope autocorrelation function is proposed to analyze their period separation. <BR /> Results: We have identified the mixed-mode signature separation thanks to their pattern that is compatible with the asymptotic law of gravity modes. We have shown that, independent of any modeling, the g-mode spacings help to distinguish the evolutionary status of a red-giant star. We then report the different seismic and fundamental properties of the stars, depending on their evolutionary status. In particular, we show that high-mass stars of the secondary clump present very specific seismic properties. We emphasize that stars belonging to the clump were affected by significant mass loss. We also note significant population and/or evolution differences in the different fields observed by CoRoT. The CoRoT space mission, launched 2006 December 27, was developed and is operated by the CNES, with participation of the Science Programs of ESA, ESAŠs RSSD, Austria, Belgium, Brazil, Germany, and Spain.Apeendix A is available in electronic form at <A href="http://www.aanda.org">http://www.aanda.org</A>
[Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie]
