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Methods developed in a previous paper on perturbations of the Schwarzschild metric are here extended to the treatment of perturbations of perfect fluid stellar models. The perturbations of a perfect fluid sphere are explicitly decomposed into their gauge invariant and gauge dependent parts and a variational principle for the perturbation equations is derived. The Hamiltonian for the perturbations is constructed and a sufficient condition for stability against nonradial, radiative perturbations is derived from it. The stability criterion is applied to two interesting classes of stellar models, polytropic white dwarf models and high-density neutron star cores with pressure proportional to energy density.
๐ SIMILAR VOLUMES
We investigate the effects of finite masses on the short-distance properties in the context of the two-dimensional Federbush model. We comment in particular on the limiting procedure in deriving the equation of motion and on changes in Wilson expansions of certain operators as compared to the massle