Gravastars in a non-minimally coupled gravity with electromagnetism

Abstract

In this paper we investigate the gravitational vacuum stars which called gravastars in the non-minimally coupled models with electromagnetic and gravitational fields. We consider two non-minimal models and find the corresponding spherically symmetric exact solutions in the interior of the star consisting of the dark energy condensate. Our models turn out to be Einstein-Maxwell model at the outside of the star and the solutions become the Reissner-Nordstrom solution. The physical quantities of these models are continuous and non-singular in some range of parameters and the exterior geometry continuously matches with the interior geometry at the surface. We calculate the matter mass, the total gravitational mass, the electric charge and redshift of the star for the two models. We notice that these quantities except redshift are dependent of a subtle free parameter, k, of the model. We also remark a wide redshift range from zero to infinity depending on one free parameter, beta, in the second model.