Charged analogue of Finch-Skea stars

TL;DR

This paper develops new solutions to Einstein-Maxwell equations describing static, charged, spherically symmetric stars, extending the Finch-Skea uncharged models to include electric charge while ensuring physical plausibility.

Contribution

It introduces three categories of solutions for charged stars, including a new charged analogue of Finch-Skea stars, with detailed physical analysis confirming their realism.

Findings

Solutions satisfy causality and speed of sound constraints

Charged models extend Finch-Skea stars to include electric charge

Models are physically realistic for static charged fluid spheres

Abstract

We present solutions to the Einstein-Maxwell system of equations in spherically symmetric gravitational fields for static interior spacetimes with a specified form of the electric field intensity. The condition of pressure isotropy yields three category of solutions. The first category is expressible in terms of elementary functions and does not have an uncharged limit. The second category is given in terms of Bessel functions of half-integer order. These charged solutions satisfy a barotropic equation of state and contain Finch-Skea uncharged stars. The third category is obtained in terms of modified Bessel functions of half-integer order and does not have an uncharged limit. The physical features of the charged analogue of the Finch-Skea stars are studied in detail. In particular the condition of causality is satisfied and the speed of sound does not exceed the speed of light. The physical analysis indicates that this analogue is a realistic model for static charged relativistic perfect fluid spheres.