Head-On Collision of Neutron Stars As A Thought Experiment

TL;DR

This paper presents an analytic argument suggesting that head-on collisions of neutron stars produce hot remnants supported by thermal pressure, preventing immediate collapse regardless of total mass, challenging previous reliance on numerical simulations.

Contribution

It introduces a relativistic, analytic approach to understanding neutron star collisions, bypassing the need for complex numerical simulations.

Findings

Thermal pressure from collisions supports the remnant against collapse.

Support holds even for remnants exceeding maximum cold neutron star mass.

The conclusion is independent of the progenitors' total mass.

Abstract

The head-on collision of identical neutron stars from rest at infinity requires a numerical simulation in full general relativity for a complete solution. Undaunted, we provide a relativistic, analytic argument to suggest that during the collision, sufficient thermal pressure is always generated to support the hot remnant in quasi-static stable equilibrium against collapse prior to slow cooling via neutrino emission. Our conclusion is independent of the total mass of the progenitors and holds even if the remnant greatly exceeds the maximum mass of a cold neutron star.