# Gravastars in $f(R,\mathcal{T})$ gravity

## TL;DR

This paper develops a novel gravastar model within $f(R, ext{T})$ gravity, describing a three-region structure with specific matter and pressure conditions, providing exact, singularity-free solutions as an alternative to black holes.

## Contribution

It introduces a new gravastar model in $f(R, ext{T})$ gravity with a detailed three-region structure and exact solutions, extending previous models in alternative gravity theories.

## Key findings

- Exact, singularity-free solutions obtained.
- Physically valid features demonstrated within $f(R, ext{T})$ gravity.
- Model supports gravastar as black hole alternative.

## Abstract

We propose a unique stellar model under the $f(R,\mathcal{T})$ gravity by using the conjecture of Mazur-Mottola [P. Mazur and E. Mottola, Report number: LA-UR-01-5067., P. Mazur and E. Mottola, Proc. Natl. Acad. Sci. USA 101, 9545 (2004)] which is known as gravastar and a viable alternative to the black hole as available in literature. This gravastar is described by the three different regions, viz., (I) Interior core region, (II) Intermediate thin shell, and (III) Exterior spherical region. The pressure within the interior region is equal to the constant negative matter density which provides a repulsive force over the thin spherical shell. This thin shell is assumed to be formed by a fluid of ultra relativistic plasma and the pressure, which is directly proportional to the matter-energy density according to Zel'dovich's conjecture of stiff fluid [Y.B. Zel'dovich, Mon. Not. R. Astron. Soc. 160, 1 (1972)], does counter balance the repulsive force exerted by the interior core region. The exterior spherical region is completely vacuum and assumed to be de Sitter spacetime which can be described by the Schwarzschild solution. Under this specification we find out a set of exact and singularity-free solution of the collapsing star which presents several other physically valid features within the framework of alternative gravity.