Thermodynamics of Plasmas workshop

Phase transition in a self-gravitating system: spontaneous orbital alignment of stars around a supermassive black hole

7 Oct 2026, 11:50

40m

Bernoulli center (EPFL)

Oral presentation Main track Self-gravitating systems

Speaker

Jean-Baptiste FOUVRY (Institut d'Astrophysique de Paris)

Description

Supermassive black holes dominate the gravitational potential in galactic nuclei. In these dense environments, stars follow nearly Keplerian orbits and see their orbital planes relax through the potential fluctuations generated by the stellar cluster itself. For typical stellar distributions, the most likely long-term outcome of this rearrangement is for the orbital planes of the most massive stars to spontaneously self-align within a narrow disc. We present a maximum entropy method to systematically determine this non-trivial long-term thermodynamical distribution. We explore the dependence of this phase transition as a function of the clusters' parameters. Presentation based on https://arxiv.org/abs/2111.09011