Light and radial velocity variations due to low-frequency oscillation in rotating stars

Jadwiga Daszynska-Daszkiewicz
Instytut Astronomiczny, Uniwersytet Wroclawski, Poland

Abstract. Low-frequency oscillations (high order g-modes) are unstable in a wide range of stellar models and have been detected in a number of B-type stars. For such modes, even a moderate rotation ( ~100 km/s) significantly affects amplitude distribution over stellar surface and hence visibility conditions in light and mean radial velocity variations. Adopting the traditional approximation, we study effects of rotation on relative amplitudes in photometric passbands and in radial velocity. After describing the formalism, we will present numerical results for a number of unstable modes in a selected stellar model of a $6M_odot$ main sequence star. We will show how the amplitudes depends on the rotation rate and on the aspect angle. We will also show the amplitude ratio vs. phase difference diagrams, which will be used in a discussion of prospects for mode identification.

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