Equilibrium of Spheres with Local Anisotropy in Postnewtonian Gravity. Application to White Dwarfs

TL;DR

This paper investigates the equilibrium states of white dwarfs with local anisotropy within post-Newtonian gravity, revealing stable configurations above the Chandrasekhar limit and emphasizing energy minimization as the equilibrium criterion.

Contribution

It introduces a new approach to white dwarf equilibrium based on energy minimization and demonstrates the existence of stable anisotropic configurations beyond the Chandrasekhar mass.

Findings

Stable anisotropic white dwarf configurations exist above the Chandrasekhar limit.

Equilibrium is determined by total energy minimization, not assumed isotropy.

Post-Newtonian gravity allows for stable anisotropic solutions.

Abstract

Static solutions of white dwarfs with spherical symmetry and local anisotropy are studied in the post-Newtonian approximation. It is argued that the condition for equilibrium must be that the total energy is a minimum for given baryon number and the question whether there is local isotropy or anisotropy inside the star should follow from that condition, rather than be postulated "a priori". It is shown show that, in post-Newtonian gravity, there are stable configurations with local anisotropy for masses above the Chandrasekhar limit.