Gravitational instability caused by the weight of heat

TL;DR

This paper explores how thermal energy influences gravitational collapse, revealing a relativistic gravothermal instability that can lead to black hole formation during supernova core collapse.

Contribution

It introduces the relativistic gravothermal instability, extending classical gravitational instability concepts to high-energy regimes and connecting it to supernova core collapse.

Findings

Identification of high-energy relativistic gravothermal instability.

Analogy between relativistic and Newtonian core-halo structures.

Implication for black hole formation in supernovae.

Abstract

Thermal energy points toward a disordered, completely uniform state acting counter to gravity's tendency to generate order and structure through gravitational collapse. It is, therefore, expected to contribute to the stabilization of a self-gravitating, classical ideal gas over collapse. However, I identified an instability that always occurs at sufficiently high energies: the high-energy or relativistic gravothermal instability. I argue here that this instability presents an analogous core--halo structure as its Newtonian counterpart, the Antonov instability. The main difference is that in the former case the core is dominated by the gravitation of thermal energy and not rest mass energy. A relativistic generalization of Antonov's instability---the low-energy gravothermal instability---also occurs. The two turning points, which make themselves evident as a double spiral of the caloric curve, approach each other as relativistic effects become more intense and eventually merge in a single point. Thus, the high and low-energy cases may be realized as two aspects of a single phenomenon---the gravothermal instability---which involves a core--halo separation and an intrinsic heat flow. Finally, I argue that the core formed during a core-collapse supernova is subject to the relativistic gravothermal instability if it becomes sufficiently hot and compactified at the time of the bounce. In this case, it will continue to collapse towards the formation of a black hole.