Dynamical gravastars from the interaction between scalar fields and matter

TL;DR

This paper introduces dynamical gravastar solutions arising from scalar field interactions with matter, showing they can mimic black hole features and confine matter, offering an alternative to classical compact objects.

Contribution

It demonstrates the existence of dynamical gravastar solutions through scalar field-matter interactions, unlike static solutions, and analyzes their properties and observational differences.

Findings

Scalar field acts like a cosmological constant internally.

Scalar field decays as a Yukawa potential externally.

Solutions exhibit stronger matter scattering than black holes.

Abstract

Gravastars are configurations of compact singularity-free gravitational objects which are interesting alternatives to classical solutions in the strong gravitational field regime. Although there are no static star-like solutions of the Einstein-Klein-Gordon equations for real scalar fields, we show that dynamical gravastars solutions arise through the direct interaction of a scalar field with matter. Two configurations presented here show that, within the internal zone, the scalar field plays a role similar to a cosmological constant, while the scalar field decays at large distances as the Yukawa potential. Like classical gravastars, these solutions exhibit small values of the temporal metric component near a transitional radial value, although this behaviour is not determined by the de Sitter nature of the internal space-time, but rather by a slowly-varying scalar field. The scalar field-matter interaction is able to define trapping forces that rigorously confine the polytropic gases to the interior of a sphere. At the surface of these spheres, pressures generated by the field-matter interaction play the role of "walls" preventing the matter from flowing out. These solutions predict a stronger scattering of the accreting matter with respect to Schwarzschild black holes.