The pulsations of the B5IVe star HD 181231 observed with CoRoT and ground-based spectroscopy

Autor: Monica Rainer, C. Buil, A. L. Huat, R. Samadi, Coralie Neiner, C. Catala, J. Suso, Juan Gutiérrez-Soto, Frédéric Baudin, Anne-Marie Hubert, A. Baglin, B. de Batz, Y. Frémat, T. Semaan, F. Espinosa Lara, Ennio Poretti, Fabien Carrier, Eduardo Janot-Pacheco, L. Andrade, P. D. Diago, Christophe Martayan, O. Thizy, Eric Michel, Marcelo Emilio, Michele Floquet, Juan Fabregat, B. Leroy, J Ribeiro
Přispěvatelé: Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Physique stellaire et galactique, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Observatoire Royal de Belgique (ORB), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Observatori Astronòmic, Universitat de València, INAF-Osservatorio Astronomico di Brera (INAF-OAB), Institute of Astronomy, Katholieke Universiteit Leuven, Shelyak Instruments, Observatoire de Castanet-Tolosan, Obervatorio do Instituto Geografico do Exercito, Universidade de São Paulo, Obervatório Astronômico, Universidade Estadual de Ponta Grossa
Rok vydání: 2009
Předmět:
Zdroj: Astronomy and Astrophysics-A&A
Astronomy and Astrophysics-A&A, 2009, 506, pp.143-151. ⟨10.1051/0004-6361/200911971⟩
ISSN: 1432-0746
0004-6361
Popis: International audience; 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.
Databáze: OpenAIRE
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