General Relativistic Decompression of Binary Neutron Stars During Dynamic Inspiral

TL;DR

This study uses numerical relativity simulations to explore how eccentric orbits in binary neutron star systems affect their stability and internal density during inspiral, revealing a stabilizing effect during close approaches.

Contribution

It demonstrates that orbital eccentricity influences neutron star stability during inspiral, showing density decreases at periastron and increases at apastron, a novel insight into binary neutron star dynamics.

Findings

Density decreases at periastron, stabilizing stars.

Density increases at apastron, leading to re-compression.

Eccentricity significantly impacts neutron star stability during inspiral.

Abstract

We investigate the dynamic stability of inspiraling neutron stars by performing multiple-orbit numerical relativity simulations of the binary neutron star inspiral process. By introducing eccentricities in the orbits of the neutron stars, significant changes in orbital separation are obtained within orbital timescales. We find that as the binary system evolves from apastron to periastron (as the binary separation decreases), the central rest mass density of each star decreases, thus stabilizing the stars against individual prompt collapse. As the binary system evolves from periastron to apastron, the central rest mass density increases; the neutron stars re-compress as the binary separation increases.