An asteroseismic study of the O9V star HD 46202 from CoRoT space-based photometry
English
Briquet, Maryline[Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie]
Aerts, C.[Instituut voor Sterrenkunde, K.U.Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium; Department of Astrophysics, IMAPP, University of Nijmegen, PO Box 9010, 6500 GL, Nijmegen, The Netherlands]
Baglin, A.[LESIA, CNRS UMR8109, Université Pierre et Marie Curie, Université Denis Diderot, Observatoire de Paris, 92195, Meudon Cedex, France]
Nieva, M. F.[Max Planck Institute for Astrophysics, Karl Schwarzschild Str. 1, Garching bei München, 85741, Germany]
Degroote, P.[Instituut voor Sterrenkunde, K.U.Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium]
Przybilla, N.[Dr. Karl Remeis Observatory & ECAP, University of Erlangen-Nuremberg, Sternwartstrasse 7, 96049, Bamberg, Germany]
Noels-Grötsch, Arlette[Université de Liège - ULg > Services généraux (Faculté des sciences) > Relations académiques et scientifiques (Sciences)]
Schiller, F.[Dr. Karl Remeis Observatory & ECAP, University of Erlangen-Nuremberg, Sternwartstrasse 7, 96049, Bamberg, Germany]
Vučković, M.[Instituut voor Sterrenkunde, K.U.Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium]
Oreiro, R.[Instituut voor Sterrenkunde, K.U.Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium]
Smolders, K.[Instituut voor Sterrenkunde, K.U.Leuven, Celestijnenlaan 200D, 3001, Leuven, Belgium]
Auvergne, M.[LESIA, CNRS UMR8109, Université Pierre et Marie Curie, Université Denis Diderot, Observatoire de Paris, 92195, Meudon Cedex, France]
[en] asteroseismology ; stars: oscillations ; stars: variables: general ; stars: early-type ; stars: individual: HD 46202
[en] The O9V star HD 46202, which is a member of the young open cluster NGC 2244, was observed by the CoRoT satellite in October/November 2008 during a short run of 34 days. From the very high-precision light curve, we clearly detect β Cep-like pulsation frequencies with amplitudes of ~0.1 mmag and below. A comparison with stellar models was performed using a χ[SUP]2[/SUP] as a measure for the goodness-of-fit between the observed and theoretically computed frequencies. The physical parameters of our best-fitting models are compatible with the ones deduced spectroscopically. A core overshooting parameter α[SUB]ov[/SUB] = 0.10 ± 0.05 pressure scale height is required. None of the observed frequencies are theoretically excited with the input physics used in our study. More theoretical work is thus needed to overcome this shortcoming in how we understand the excitation mechanism of pulsation modes in such a massive star. A similar excitation problem has also been encountered for certain pulsation modes in β Cep stars recently modelled asteroseismically. The CoRoT space mission was developed and is operated by the French space agency CNES, with the participation of ESA's RSSD and Science Programmes, Austria, Belgium, Brazil, Germany, and Spain.
[Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie]
