Anisotropic dark energy stars

TL;DR

This paper models anisotropic dark energy stars with phase transitions, revealing conditions for non-singular black hole solutions and analyzing their structure, stability, and mass-radius relations.

Contribution

It introduces a novel model of dark energy stars with anisotropic properties and phase transitions, extending previous gravastar models with new stability and structure insights.

Findings

Existence of a critical coupling parameter for non-singular black holes

Mass-radius relations indicating black hole formation is inevitable

Hydrodynamic stability analyzed through standard mass-radius tests

Abstract

A model of compact object coupled to inhomogeneous anisotropic dark energy is studied. It is assumed a variable dark energy that suffers a phase transition at a critical density. The anisotropic Lambda-Tolman-Oppenheimer-Volkoff equations are integrated to know the structure of these objects. The anisotropy is concentrated on a thin shell where the phase transition takes place, while the rest of the star remains isotropic. The family of solutions obtained depends on the coupling parameter between the dark energy and the fermion matter. The solutions share several features in common with the gravastar model. There is a critical coupling parameter that gives non-singular black hole solutions. The mass-radius relations are studied as well as the internal structure of the compact objects. The hydrodynamic stability of the models is analyzed using a standard test from the mass-radius relation. For each permissible value of the coupling parameter there is a maximum mass, so the existence of black holes is unavoidable within this model.