Driving and damping mechanisms in hybrid pressure-gravity modes pulsators

Abstract. We study the energetic aspects of hybrid pressure-gravity modes pulsations. The case of hybrid β Cephei-SPB pulsators is considered with special attention. In addition to the already known sensitivity of the driving mechanism to the heavy elements mixture (mainly the iron abundance), we show that the characteristics of the propagation and evanescent regions play also a major role, determining the extension of the stable gap in the frequency domain between the unstable low order pressure and high order gravity modes. Finally, we consider the case of hybrid δ Sct-γ Dor pulsators.