Gravastars with Dark Energy Evolving to Naked Singularity

TL;DR

This paper explores gravastar models composed of anisotropic dark energy and a thin shell, revealing scenarios where they evolve into stable gravastars, black holes, or naked singularities, including the novel formation of naked singularities from gravastars.

Contribution

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

Findings

Stable gravastars with oscillating shells identified.

Collapse into black holes or naked singularities shown under certain conditions.

First demonstration of naked singularity formation from a gravastar model.

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 constituted of dark and repulsive dark energy, as also shown in previous work. Besides, in three cases 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.