Connection between nonradial pulsations and stellar winds in massive stars. I. Nonradial pulsation theory of massive stars

In the context of recent observations involving the use of high-precision spectroscopy, it is now believed that nonradial pulsations (NRP) occur everywhere among massive stars. Certain observations have suggested a possible connection between the NRP phenomenon and the episodic mass loss in Be stars. The excitation mechanisms of NRP in massive stars are discussed, taking into account overstable convection modes, the Kelvin-Helmholtz instability of differentially rotating stars, and the resonant generation of NRP waves by tidal bulge waves. It is pointed out that one of the most important aspects of nonaxisymmetric NRP waves is that they can transport angular momentum from one part of the star to another when they are nonconservative. Attention is given to the angular momentum transport by NRP waves and the Be episode. 8 references