Moment of inertia of slowly rotating anisotropic neutron stars in $f(R,T)$ gravity

TL;DR

This paper explores how $f(R,T)$ gravity, specifically the $R+ 2eta T$ model, affects the structure and properties of slowly rotating anisotropic neutron stars, revealing increased radii and potential for higher masses consistent with observations.

Contribution

It derives modified TOV equations and moment of inertia expressions within $f(R,T)$ gravity, highlighting the impact of the $2eta T$ term on neutron star properties.

Findings

Surface radius increases at low central densities due to $2eta T$ term.

Mass and moment of inertia are slightly modified by the $2eta T$ term.

Anisotropy allows for higher neutron star masses compatible with observations.

Abstract

Within the framework of $f(R,T)$ theories of gravity, we investigate the hydrostatic equilibrium of anisotropic neutron stars with a physically relevant equation of state (EoS) for the radial pressure. In particular, we focus on the $f(R,T) = R+ 2\beta T$ model, where $\beta$ is a minimal coupling constant. In the slowly rotating approximation, we derive the modified TOV equations and the expression for the relativistic moment of inertia. The main properties of neutron stars, such as radius, mass and moment of inertia, are studied in detail. Our results revel that the main consequence of the $2\beta T$ term is a substantial increase in the surface radius for low enough central densities. Nevertheless, such a term slightly modifies the total gravitational mass and moment of inertia of the slowly rotating stars. Furthermore, the changes are noticeable when anisotropy is incorporated into the stellar fluid, and it is possible to obtain higher masses that are consistent with the current observational data.