ON THE STRUCTURE AND SECULAR STABILITY OF PLANE-PARALLEL STELLAR OBJECTS

The structure of self-gravitating, plane-parallel, vertically stratified stellar objects, with the energy generation and opacity given by the power laws epsilon = epsilon0rhoT(eta), kappa = kappa0rho(alpha)T(-beta), is studied. It is shown that the condition for secular stability in such objects is 5 + alpha + beta - eta > 0, whereas for spherical stars the corresponding condition is eta + beta - 3 - 3alpha > 0. Exact solutions (in closed form) are presented both for fully radiative models and for models with a convective central region. Approximate analytic solutions are given for models with a convective central region and radiative outer layers. Numerical models are readily calculated.