http://arxiv.org/abs/1809.04408
Thermal energy points towards 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 in Ref. [1] an instability that always sets in at sufficiently high energies, the
high-energy 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, thelow-energy gravothermal instability’, does also occur. The two turning points approach each other as relativistic effects become more intense and eventually merge at a single point. Thus, they may be realized as two aspects of a single phenomenon. I also investigate the implicit thermodynamic sector of General Relativity and show that the relativistic equation of hydrostatic equilibrium, the Tolman and Klein relations, and the redshift factor, all do follow from the second law of thermodynamics for any equation of state. The concentration of heat at lower gravitational potential and the local temperature gradient are dictated by the maximization of entropy. 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.
Z. Roupas
Thu, 13 Sep 18
60/68
Comments: N/A