Analytic Approximations to the Mass-Radius Relation and Energy of Zero-Temperature Stars

Abstract

The variational principle is applied to two approximate forms of the energy integral of a star at zero temperature in order to obtain analytic expressions for the mass-radius relation and for the energy Several well-known equations of state are considered, and the effects of rotation and of stored magnetic fields are included Comparison of the approximations with published numerical solutions of the exact equations sbo good agreement.