The B0.5IVe CoRoT target HD 49330^*

I. Photometric analysis from CoRoT data

¹ GEPI, Observatoire de Paris, CNRS, Université Paris Diderot, 5 place Jules Janssen, 92190 Meudon, France e-mail: anne-laure.huat@obspm.fr
² Institut d'Astrophysique Spatiale (IAS), Bâtiment 121, 91405 Orsay Cedex, France
³ Royal Observatory of Belgium, 3 avenue circulaire, 1180 Brussel, Belgium
⁴ University of Sao Paulo, Brasil
⁵ Observatori Astronòmic de la Universitat de València, ED. Instituts d'Investigació, Poligon La Coma, 46980 Paterna, València, Spain
⁶ Obervatório Asrtonômico, Universidade Estadual de Ponta Grossa, Av. Carlos Cavalcanti, 4748 Ponta Grossa, Paraná, Brazil
⁷ LESIA, Observatoire de Paris, CNRS, UPMC, Université Paris Diderot, 5 place Jules Janssen, 92190 Meudon, France

Received: 23 February 2009
Accepted: 5 June 2009

Abstract

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.