Gravastars with an Interior Dark Energy Fluid Forming a Naked Singularity

TL;DR

This paper explores gravastar models with anisotropic dark energy interiors and thin shells, revealing conditions under which they form stable structures, black holes, or naked singularities, including the novel emergence of naked singularities from gravastars.

Contribution

It introduces a gravastar model with anisotropic dark energy and demonstrates for the first time that naked singularities can form from such models.

Findings

Stable gravastars with oscillating shells

Collapse into black holes or naked singularities

Naked singularities can emerge from gravastar configurations

Abstract

We consider a gravastar model made of anisotropic dark energy with an infinitely thin spherical shell of a perfect fluid with the equation of state $p = (1-\gamma)\sigma$ with an external de Sitter-Schwarzschild region. It is found that in some cases the models represent the "bounded excursion" stable gravastars, where the thin shell is oscillating between two finite radii, while in other cases they collapse until the formation of black holes or naked singularities. An interesting result is that we can have black hole and stable gravastar formation even with an interior and a shell cons tituted of dark and repulsive dark energy, as also shown in previous work. Besides, in one case we have a dynamical evolution to a black hole (for $\Lambda =0$) or to a naked singularity (for $\Lambda > 0$). This is the first time in the literature that a naked singularity emerges from a gravastar model.