Isotropic star in low-mass X-ray binaries and X-ray pulsars

TL;DR

This paper models isotropic compact stars in low-mass X-ray binaries and X-ray pulsars, deriving key physical parameters that align with observed data, using a specific metric and algebraic field equations.

Contribution

It introduces a simplified algebraic model for isotropic compact stars in LMXBs and X-ray pulsars that satisfies all physical and stability conditions, matching observed data.

Findings

Derived mass, density, pressure, and red-shift values consistent with observations.

Confirmed stability via adiabatic index > 4/3.

All energy and stability conditions satisfied for candidate stars.

Abstract

We present a model for compact stars in the low mass X-ray binaries(LMXBs) and X-ray pulsars using a metric given by John J. Matese and Patrick G. Whitman \citep{Matese and Whitman1980}. Here the field equations are reduced to a system of two algebraic equations considering the isotropic pressure. Compact star candidates 4U 1820-30(radius=10km) in LMXBs, and Her X-1(radius=7.7km), SAX J 1808.4-3658(SS1)(radius=7.07km) and SAX J 1808.4-3658(SS2)(radius=6.35km) in X-ray pulsars satisfy all the energy conditions, TOV-equation and stability condition. From our model, we have derived mass($M$), central density($\rho_{0}$), suface density($\rho_{b}$), central pressure($p_{0}$), surface pressure($p_{b}$) and surface red-shift($Z_{s}$) of the above mentioned stars, which are very much consistant with the observed/reported datas\citep{N. K. Glendenning1997,Gondek2000}. We have also observe the adiabatic index($\gamma$>4/3) of the above steller objects.