White Dwarfs with Anisotropic Pressure in Postnewtonian Gravity

Abstract

The theory of equilibrium of nonrotating, spherically symmetric neutron stars and white dwarfs is revisited. We propose that the condition for equilibrium is that the total energy is a minimum, for given baryon number, amongst configurations fulfilling Einstein's equations. The isotropy of the stress tensor is not assumed 'a priori'. Using this condition it is shown that, in post-Newtonian gravity, there are equilibrium configurations of white dwarfs, with local anisotropy, having mass above the Chandrasekhar limit.