Role of pressure anisotropy on relativistic compact stars

TL;DR

This paper models relativistic compact stars with pressure anisotropy using specific geometric and physical assumptions, analyzing their stability, physical features, and applicability to observed compact star candidates.

Contribution

It introduces a new anisotropic stellar model employing a specific metric potential and anisotropy function, providing insights into stability and physical properties of compact stars.

Findings

Model satisfies physical acceptability conditions.

Results applicable to strange stars like Her X-1 and SMC X-1.

Analyzes stability and physical features of anisotropic stars.

Abstract

We investigate a compact spherically symmetric relativistic body with anisotropic particle pressure profiles. The distribution possesses characteristics relevant to modeling compact stars within the framework of general relativity. For this purpose, we consider a spatial metric potential of Korkina and Orlyanskii [Ukr. Phys. J. 36, 885 (1991)] type in order to solve the Einstein field equations. An additional prescription we make is that the pressure anisotropy parameter takes the functional form proposed by Lake [Phys. Rev. D 67, 104015 (2003)]. Specifying these two geometric quantities allows for further analysis to be carried out in determining unknown constants and obtaining a limit of the mass-radius diagram, which adequately describes compact strange star candidates like Her X-1 and SMC X-1. Using the anisotropic Tolman-Oppenheimer-Volkoff equations, we explore the hydrostatic equilibrium and the stability of such compact objects. Then, we investigate other physical features of this models, such as the energy conditions, speeds of sound and compactness of the star in detail and show that our results satisfy all the required elementary conditions for a physically acceptable stellar model. The results obtained are useful in analyzing the stability of other anisotropic compact objects like white dwarfs, neutron stars, and gravastars.