Effects of Differential Rotation on the Maximum Mass of Neutron Stars

TL;DR

This paper investigates how differential rotation influences the maximum mass of neutron stars by numerically modeling them in general relativity, considering various rotation profiles and equations of state.

Contribution

It provides the first systematic numerical analysis of maximum neutron star mass under differential rotation with variable stiffness in the equation of state.

Findings

Maximum mass increases with differential rotation

Stiffer equations of state allow higher maximum masses

Differential rotation significantly impacts neutron star stability

Abstract

The merger of binary neutron stars is likely to lead to differentially rotating remnants. In this paper we numerically construct models of differentially rotating neutron stars in general relativity and determine their maximum allowed mass. We model the stars adopting a polytropic equation of state and tabulate maximum allowed masses as a function of differential rotation and stiffness of the equation of state. We also provide a crude argument that yields a qualitative estimate of the effect of stiffness and differential rotation on the maximum allowed mass.