Compact stars with quadratic equation of state

TL;DR

This paper derives new exact solutions for compact stars using Einstein-Maxwell equations with a quadratic equation of state, incorporating anisotropy and charge, and matches observed stellar masses.

Contribution

It introduces a novel class of solutions with a quadratic EoS, extending previous linear models, and applies them to real star data with detailed physical analysis.

Findings

Models include observed stellar masses.

Solutions are physically reasonable for specific stars.

Generalizes previous linear EoS models.

Abstract

We provide new exact solutions to the Einstein-Maxwell system of equations for matter configurations with anisotropy and charge. The spacetime is static and spherically symmetric. A quadratic equation of state is utilised for the matter distribution. By specifying a particular form for one of the gravitational potentials and the electric field intensity we obtain new exact solutions in isotropic coordinates. In our general class of models, an earlier model with a linear equation of state is regained. For particular choices of parameters we regain the masses of the stars PSR J1614-2230, 4U 1608-52, PSR J1903+0327, EXO 1745-248 and SAX J1808.4-3658. A comprehensive physical analysis for the star PSR J1903+0327 reveals that our model is reasonable.