Higher mass limits of neutron stars from the equation of states in curved spacetime

TL;DR

This paper demonstrates that incorporating gravitational time dilation effects into the equation of state calculations for neutron stars significantly increases their predicted maximum mass limits, providing a more accurate modeling approach.

Contribution

It introduces a first-principle method to include curved spacetime effects in the equation of state calculations for neutron stars, leading to higher mass limit predictions.

Findings

Maximum mass limit increases from 1.61 to 2.24 solar masses

Inclusion of gravitational time dilation effects is crucial for accurate neutron star modeling

Curved spacetime effects lead to substantially higher mass estimates

Abstract

In order to solve the Tolman-Oppenheimer-Volkoff equations for neutron stars, one routinely uses the equation of states which are computed in the Minkowski spacetime. Using a first-principle approach, it is shown that the equation of states which are computed within the curved spacetime of the neutron stars include the effect of gravitational time dilation. It arises due to the radially varying interior metric over the length scale of the star and consequently it leads to a much higher mass limit. As an example, for a given set of parameters in a $\sigma-\omega$ model of nuclear matter, the maximum mass limit is shown to increase from $1.61 M_{\odot}$ to $2.24 M_{\odot}$ due to the inclusion of gravitational time dilation.