Linear Analysis

Abstract

We discuss the general strategy of the theoretical description of stellar stability and pulsations. The initial construction of a spherically symmetric stellar model in hydrostatic equilibrium is followed by considering small perturbations around the equilibrium. Both for radial and nonradial disturbances the linear equations governing these small perturbations are derived. The influence of the thermal and the dynamical timescale on the properties of linear pulsations is discussed in detail. For unstable stellar models the last step of the general approach consists of following the evolution of an instability into the nonlinear regime by numerical simulation.