Radiating Gravastars

TL;DR

This paper models dynamical gravastars with a radiating shell in Vaidya spacetime, showing they can evolve into black holes, stable or unstable gravastars, or bounded excursions, depending on initial conditions and parameters.

Contribution

It introduces the first model of a radiating gravastar and analyzes its possible final states based on shell dynamics and cosmological constant effects.

Findings

Final states include black holes, unstable gravastars, stable gravastars, and bounded excursions.

The model demonstrates the impact of shell mass evolution and cosmological constant on outcomes.

First literature example of a gravastar emitting radiation.

Abstract

Considering a Vaidya exterior spacetime, we study dynamical models of prototype gravastars, made of an infinitely thin spherical shell of a perfect fluid with the equation of state $p = \sigma$, enclosing an interior de Sitter spacetime. We show explicitly that the final output can be a black hole, an unstable gravastar, a stable gravastar or a "bounded excursion" gravastar, depending on how the mass of the shell evolves in time, the cosmological constant and the initial position of the dynamical shell. This work presents, for the first time in the literature, a gravastar that emits radiation.