Pulsations in the late-type Be star HD 50 209 detected by CoRoT
2 GEPI - Galaxies, Etoiles, Physique, Instrumentation
3 Physique stellaire et galactique
4 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
5 ROB - Royal Observatory of Belgium = Observatoire Royal de Belgique
6 IAA-CSIC - Instituto de Astrofísica de Andalucía = Institute of Astrophysics of Andalusia
7 Departamento de Astronomia Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo
8 Obervatório Astronômico, Universidade Estadual de Ponta Grossa
9 OAB - INAF - Osservatorio Astronomico di Brera
Résumé
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 muHz).
Conclusions: HD 50 209 is a pulsating Be star as expected from its position in the HR diagram, close to the SPB instability strip.