Maximum mass of singularity-free anisotropic compact stars in Rastall theory of gravity

TL;DR

This paper models singularity-free anisotropic compact stars in Rastall gravity, deriving solutions that show increased maximum mass with the Rastall parameter, aligning with observational data and satisfying physical conditions.

Contribution

It introduces a new singularity-free model for anisotropic stars in Rastall gravity, analyzing maximum mass and radius variations with the Rastall parameter.

Findings

Maximum mass increases with Rastall parameter $\xi$

Predicted radii match observed pulsar data

Model satisfies causality, energy, and stability criteria

Abstract

The current model explores spherically symmetric anisotropic compact stars within the Rastall theory of gravity. By employing the Krori and Barua metric ansatz (K.D. Krori and J. Barua, J. Phys. A: Math. Gen. 8 (1975) 508), we derive a set of tractable, singularity-free relativistic solutions to the Einstein field equations. Using a best-fit equation for the numerical solution of the TOV equation, we determine the maximum mass and corresponding radius in this model. Our findings reveal that an increase in the Rastall parameter $(\xi)$ leads to a higher maximum mass, indicating a stiffer nature of the equation of state. For $\xi$ values ranging from 0.01 to 0.09, we calculate the maximum mass to be between $2.24M_{\odot}$ and $2.36M_{\odot}$, with corresponding radii from 9.48 to 10.15 km. Furthermore, our model's predictions for the radii of recently observed pulsars are consistent with observational data. The model satisfies essential criteria for causality, energy conditions, and stability, confirming its viability and physical acceptability as a stellar structure.