Gravastars in a non-minimally coupled gravity with electromagnetism

Özcan Sert,Muzaffer Adak

doi:10.1140/epjc/s10052-021-09804-3

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–Nordström 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.

Highlights

IntroductionExact interior and exterior solutions describing mixed relativistic stars which contain dark energy and ordinary matter were found in [22] for the model with phantom scalar field and they matched continuously at the surface of the star
The inside of the gravastar has the dark energy matter which has the equation of state ρ = − p, while the outside of the star is considered as a vacuum described by Reissner– Nordström geometry
Has the equation of state p = −ρ and the exterior is vacuum describing by the Reissner–Nordström geometry

Summary

Introduction

Exact interior and exterior solutions describing mixed relativistic stars which contain dark energy and ordinary matter were found in [22] for the model with phantom scalar field and they matched continuously at the surface of the star. In this study we give two exact non-singular gravastar solutions to the non-minimal Y (R)F2 gravity by considering the dark energy equation of state, p = −ρ. This model turns out to be the Einstein–Maxwell model at the exterior of the gravastar and their solutions to be the Reissner–Nordström solution

A non-minimal model for the gravastars

Spherically symmetric exact solutions

Solution-1

Solution-2

Conclusion