Seismology and activity of the F type star HD 49933

Benoît Mosser (1) , François Bouchy (2) , Claude Catala (1) , Eric Michel (1) , Reza Samadi (1) , Frédéric Thévenin (3) , Patrick Eggenberger (4) , Danuta Sosnowska (4) , Claire Moutou (2) , Annie Baglin (1)

1 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
2 LAM - Laboratoire d'Astrophysique de Marseille
3 CASSIOPEE - Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides
4 ObsGE - Observatoire Astronomique de l'Université de Genève

A 10-night asteroseismic observation programme has been conducted in January 2004 with the spectrometer Harps at the ES0 3.6-m telescope. The selected target, the 6th magnitude F5V star HD 49933, was chosen among the prime candidates of Corot, the European space mission dedicated to characterize stellar oscillations mode with high precision photometry measurements. This star shows important line profiles variations, indicating a surprisingly high activity with respect to its low rotation rate. However, with the help of tools developed for disentangling the signatures of activity and oscillations, we are able to observe its oscillation spectrum in the frequency range [1.2, 2.2 mHz]. We measure the large separation (88.7+-0.4 microHz) and the maximum amplitude (around 0.4+-0.1 m/s rms), respectively in agreement and marginal agreement with the predicted values.

Mots clés: techniques: radial velocities; stars: oscillations; techniques: radial velocities

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]

Benoît Mosser, François Bouchy, Claude Catala, Eric Michel, Reza Samadi, et al.. Seismology and activity of the F type star HD 49933. Astronomy and Astrophysics - A&A, 2005, 431L, pp.13. ⟨10.1051/0004-6361:200500003⟩. ⟨hal-00003982⟩