Radiative gravastar with thermal spectrum; Sudden vacuum condensation without gravitational collapse

TL;DR

This paper investigates quantum particle creation during gravastar formation, demonstrating that thermal radiation is emitted immediately after formation due to geometric change and vacuum condensation, providing insights into gravastar thermodynamics.

Contribution

It introduces a new toy model of gravastar formation via sudden vacuum condensation, showing thermal radiation emission in this scenario.

Findings

Thermal radiation is emitted immediately after gravastar formation.

Radiation results from geometric change and gravitational vacuum condensate.

The model confirms thermal emission consistent with previous studies.

Abstract

The gravastar is an exotic compact object proposed as a final product of gravitational collapse of a massive object in order to resolve problems associated with black holes. It is enclosed by a thin crust and the inside of it is occupied by the positive cosmological constant. Recently, the present authors studied quantum particle creation through spherically symmetric gravitational collapse to form a gravastar, and showed that the newly formed gravastar emits thermal radiation with the Gibbons-Hawking temperature of its de Sitter core. In this paper, in order to understand more about the thermal radiation associated with the gravastar formation, we investigate the quantum particle creation in another toy model of the gravastar formation; a star with the hollow inside suddenly becomes a gravastar through gravitational vacuum condensation. We find that the thermal radiation is emitted from the gravastar just formed also in the present model. The thermal radiation from the gravastar just formed comes from the change of the geometry inside the star accompanied by gravitational vacuum condensate.