Can Charged Stars be Singularity-Free?

Abstract

While the configuration of a static spherically symmetric distribution of perfect fluid in an electric field has received extensive attention in the literature, only a few works have investigated the conformally flat case. The model exhibits a remarkable property being regular or singularity free is proposed. This is unexpected given that Coulombic repulsion opposes the collapse of a star to the center generally making the center unreachable. The conformally flat geometry thus enables the approach to the center of a charged star as shown in our model. Presently there is no known reported exact model that satisfies all the elementary requirements for physical acceptability. Some reported models that have claimed to be physically reliable have been shown to be deficient. The conditions for the existence of physically relevant models and show that exact solutions satisfying the conditions exist is investigated. Then a model satisfying all the requirements with isotropic particle pressure graphically for a carefully chosen parameter space is exhibited. The model admits a barotropic equation of state. The interior spacetime is successfully matched to the exterior Reissner-Nordstrom metric. The causality criterion as well as the adiabatic stability lower bound of Chandrasekar are shown to hold. The energy conditions are also valid within the stellar radius. Other interesting models are considered.