The Gravothermal Instability at all scales: from Turnaround Radius to Supernovae

TL;DR

This paper explores gravitational instabilities across all scales, from cosmic structures to supernovae, highlighting the roles of dark energy and high-energy effects in stability and collapse.

Contribution

It introduces the concept of a turnaround radius influenced by dark energy and extends the maximum mass limit calculations for neutron cores to finite temperatures.

Findings

Dark energy can restore thermal stability at large scales.

A high-energy relativistic gravothermal instability occurs at small scales.

Extended Oppenheimer-Volkov limit to finite temperature regimes.

Abstract

The gravitational instability, responsible for the formation of the structure of the Universe, occurs below energy thresholds and above spatial scales of a self-gravitating expanding region, when thermal energy can no longer counterbalance self-gravity. I argue that at sufficiently-large scales, dark energy may restore thermal stability. This stability re-entrance of an isothermal sphere defines a turnaround radius, which dictates the maximum allowed size of any structure generated by gravitational instability. On the opposite limit of high energies and small scales, I will show that an ideal, quantum or classical, self-gravitating gas is subject to a high-energy relativistic gravothermal instability. It occurs at sufficiently-high energy and small radii, when thermal energy cannot support its own gravitational attraction. Applications of the phenomenon include neutron stars and core-collapse supernovae. I also extend the original Oppenheimer--Volkov calculation of the maximum mass limit of ideal neutron cores to the non-zero temperature regime, relevant to the whole cooling stage from a hot proto-neutron star down to the final cold state.