The Stellar Radial Pulsation Coupled with the Convection

Abstract

Abstract The generalization of Vitense’s mixing-length theory to the time-dependent case is formulated and applied to the problem of the thermodynamic coupling between the radial pulsation and the convection. Then the pulsational stability of a star with an extended convective envelope is studied with the help of Baker’s one-zone approximation applied to the linearized equations of pulsation. The stability is shown to depend sensitively on the location of the semi-ionization zone within the envelope and on the ratio of the time scale of convection with the pulsation period. The physical condition which favors instability is discussed.