Anisotropic Compact Stars in Rastall-Rainbow Gravity

TL;DR

This paper explores how anisotropic pressure and Rastall-Rainbow gravity influence neutron star structure, showing that their combined effects can explain observed stellar masses and potentially solve the hyperon puzzle.

Contribution

It introduces a novel analysis of anisotropic neutron stars within Rastall-Rainbow gravity using realistic equations of state, highlighting the impact on mass and radius predictions.

Findings

Anisotropy significantly affects neutron star mass and radius.

Rastall-Rainbow gravity combined with anisotropy yields results consistent with observations.

The hyperon puzzle can be addressed by considering anisotropic effects in this framework.

Abstract

In this work, we have investigated anisotropic neutron stars in the framework of Rastall-Rainbow gravity. All our calculations were computed using the IU-FSU realistic equation of state (EoS), in which was considered two cases: standard nucleonic composition and the one with the eight lightest baryons. From the neutron star masses and radii obtained we conclude that anisotropic pressure has significant consequences on the structure of stellar objects. In particular, when anisotropy is considered within the general relativity framework, it significantly modifies the maximum stellar mass. On the other hand, when Rastall-Rainbow gravity and anisotropy are simultaneously considered, they provide the best results for mass and radius values, including important astrophysical objects such as the LMXB NGC 6397 and the extremely massive pulsar millisecond MSP J0740 + 6620. Although the expected inclusion of hyperons in the nuclear model reproduces stellar masses smaller than those produced by standard nucleonic matter, we shown that the hyperon puzzle problem can be solved by including anisotropic effects on compact stars in the context of the Rastall-Rainbow gravity.