Charged gravitating spheres in EGB gravity

Abstract

We investigate the behaviour of charged, static, spherically symmetric matter distributions in Einstein–Gauss–Bonnet (EGB) gravity. We impose pressure isotropy on our system and analyse the resulting charged condition of pressure isotropy. This equation is an Abel differential equation of the second kind and exact solutions are found by requiring that it is separable. The condition of separability leads naturally to specific forms for the electric field intensity. Matching at the surface of the star shows that the total charge within the star depends on hypergeometric functions which is different from earlier treatments. The Gauss–Bonnet contribution to the mass of the star depends on spacetime dimension, the radius of the star and the Gauss–Bonnet coupling parameter. This Gauss–Bonnet contribution leads to behaviour different from general relativity; specifically it grows with increasing radius and increases the overall mass.