A study of neutron stars in $D \ge 4$ dimensions

TL;DR

This study extends the equations governing neutron stars to higher dimensions, numerically solving them for 4 to 7 dimensions, revealing that increased dimensionality reduces maximum mass and compactness, but stars remain within physical limits.

Contribution

It provides a numerical analysis of neutron star properties in higher-dimensional spacetimes using a standard 4D equation of state, linking observable features to spacetime dimensionality.

Findings

Maximum neutron star mass decreases with higher dimensions

Stars become less compact as dimensionality increases

Neutron stars do not violate the compactness limit in higher dimensions

Abstract

The relativistic equations of hydrostatic equilibrium for a spherically symmetric star, or the Tolman-Oppenheimer-Volkoff equations are known in higher dimensions. In this paper, these equations have been expressed in terms of parameters of 4 dimensional spacetime and solved numerically for 4, 5, 6, and 7 dimensions using a standard equation of state for the neutron star matter derived for the 4 dimensional spacetime. It has been shown that with the increase of the dimensionality, the maximum value of the mass of the neutron star decreases and the stars become less compact. Thus, although the compactness limit decreases with increased dimensionality, neutron stars never violate this limit. Simultaneous measurements of the mass, radius, and gravitational redshift for a neutron star might enable us to conclude about the central density, equation of state and the dimensionality of the spacetime in and around the star.