Alternative model of the Antonov problem

TL;DR

This paper introduces an alternative astrophysical model that naturally incorporates system size as a consequence of particle evaporation, unifying isothermal and polytropic profiles and addressing limitations of traditional models.

Contribution

It proposes a new energetic prescription for confining particles, leading to an alternative Antonov model that unifies isothermal and polytropic profiles and naturally determines system size.

Findings

The model exhibits gravitational collapse and negative specific heat regions.

System size emerges from particle evaporation without external confinement.

Unifies isothermal and polytropic profiles in a single framework.

Abstract

Astrophysical systems will never be in a real Thermodynamic equilibrium: they undergo an evaporation process due to the fact that the gravity is not able to confine the particles. Ordinarily, this difficulty is overcome by enclosing the system in a rigid container which avoids the evaporation. We proposed an energetic prescription which is able to confine the particles, leading in this way to an alternative version of the Antonov isothermal model which unifies the well-known isothermal and polytropic profiles. Besides of the main features of the isothermal sphere model: the existence of the gravitational collapse and the energetic region with a negative specific heat, this alternative model has the advantage that the system size naturally appears as a consequence of the particles evaporation.