NONRADIAL PULSATIONS AND STABILITY OF MASSIVE STARS

A non-radial non-adiabatic linear stability analysis of stellar models with initial masses on the zero-age main sequence (ZAMS) between 20 a nd 80 M. is presented. Two groups of dynamical mode-coupling instabili ties are identified. We examine the influence of the treatment of conv ection on these instabilities, as well as their dependence on the stel lar mass and the harmonic degree I of the perturbation. The instabilit ies are discussed within the context of a recently proposed model for strange-mode instabilities.