Stability of $d$-dimensional Gravastars with Variable Equation of State

TL;DR

This study investigates the stability of higher-dimensional gravastars with variable equations of state, finding that stability is achievable only with specific matter models and exterior geometries.

Contribution

It introduces the analysis of $d$-dimensional gravastars with variable equations of state, demonstrating conditions for their stability under radial perturbations.

Findings

Stable gravastars require variable matter equations of state.

Unstable for barotropic, Chaplygin, and phantomlike models.

Stability achieved with generalized variable models and specific exterior geometries.

Abstract

In this paper, we are interested to explore stable configurations of $d$-dimensional gravastars constructed from the interior $d$-dimensional de Sitter and exterior $d$-dimensional Schwarzschild/Reissner-Nordstr\"om (de Sitter) black holes through cut and paste approach. We consider the linearized radial perturbation preserving the original symmetries to explore their stability by using three different types of matter distributions. The resulting frameworks represent unstable structures for barotropic, Chaplygin, and phantomlike models for every considered choice of exterior geometries. However, matter contents with variable equations of state have a remarkable role to maintain the stability of gravastars. We conclude that stable structures of gravastars are obtained only for generalized variable models with exterior $d$-dimensional Schwarzschild/Reissner-Nordstr\"om-de Sitter black holes.