Modeling of non-rotating neutron stars in 5D Einstein-Gauss-Bonnet gravity

TL;DR

This paper models anisotropic magnetized static neutron stars in five-dimensional Einstein-Gauss-Bonnet gravity, demonstrating that higher dimensions and the Gauss-Bonnet term improve stability and allow for higher maximum masses compared to traditional four-dimensional models.

Contribution

It introduces a novel 5D Einstein-Gauss-Bonnet framework for neutron star modeling, deriving generalized TOV equations and analyzing stability and physical properties with the AV18 potential.

Findings

Higher dimensions increase maximum neutron star mass.

All energy and stability conditions are satisfied for specific coupling constants.

The modified Buchdahl inequality holds in the 5D EGB model.

Abstract

This study investigates the modeling of anisotropic magnetized static neutron stars within the framework of five-dimensional Einstein-Gauss-Bonnet (5D EGB) gravity. While Einstein's gravity has traditionally been employed to examine neutron stars, recent observational advancements have revealed its limitations in accurately describing high-mass astronomical objects-particularly in predicting or explaining certain observed neutron star masses. In response, this research seeks to address the limitations of Einstein's gravity in characterizing high-mass neutron stars by modifying the gravitational action and incorporating the Gauss-Bonnet term. This term holds significant dynamical relevance in higher dimensions, particularly within the context of five-dimensional Einstein-Gauss-Bonnet (EGB) gravity explored in this study, thereby providing a more realistic description of gravitational phenomena under extreme conditions. By deriving the generalized Tolman-Oppenheimer-Volkoff equations for five-dimensional Einstein-Gauss-Bonnet gravity and utilizing the AV18 potential, we analyze the profiles of metric functions, density and pressure, gradients of density and pressure, the anisotropic function and its trace, mass-function and compactness, the mass-radius curve, surface redshift function, equation of state parameters, and radial and tangential sound speeds. Additionally, stability factors, adiabatic indices, and energy conditions are examined. The results indicate that all conditions are satisfied for specific values of the coupling constant, confirming the physical stability of the model. Furthermore, higher dimensions enhance resistance to gravitational collapse, resulting in an increase in the maximum mass predicted by the proposed model. Ultimately, calculations show that the modified Buchdahl inequality is satisfied as well.