Dynamical Gravastars

TL;DR

This paper develops a model of gravastars combining Weyl-invariant dark energy and a specific interior equation of state, using the TOV equation to dynamically determine their structure and radii.

Contribution

It introduces a new framework for gravastar structure governed by an invariant dark energy action and the TOV equation, with radii emerging from the dynamics rather than being predefined.

Findings

Structure of gravastars determined by the action and equation of state

Existence of a small black hole wind when cosmological constant is nonzero

Mathematica notebooks demonstrate the model's dynamics

Abstract

We combine the ideas of a Weyl scaling invariant dark energy action, which eliminates black hole horizons, with the ``gravastar'' idea of a jump in the hole interior from a normal matter equation of state to an equation of state where pressure plus density approximately sum to zero. Using the Tolman-Oppenheimer-Volkoff equation, which requires continuous pressure, we present Mathematica notebooks in which the structure of the gravastar is entirely governed by the action and the equation of state, with the radii where structural changes occur emerging from the dynamics, rather than being specified in advance. The notebooks work even with zero cosmological constant, but when the cosmological constant is nonzero, there is a very small black hole ``wind'' that we calculate by a relativistic extension of standard pressure driven isothermal stellar wind theory.