Gravitational Perfect Fluid Collapse in f(R) Gravity

TL;DR

This paper studies the gravitational collapse of perfect fluids in f(R) gravity, revealing how the constant scalar curvature term influences collapse dynamics and acts similarly to a cosmological constant.

Contribution

It introduces a model of perfect fluid collapse in f(R) gravity with constant Ricci scalar, deriving junction conditions and analyzing horizon formation, extending previous GR results.

Findings

Constant Ricci scalar acts as a repulsive force slowing collapse.

f(R_0) behaves like a cosmological constant in collapse dynamics.

Collapse rate is affected by the scalar curvature term.

Abstract

In this paper, we investigate spherically symmetric perfect fluid gravitational collapse in metric $f(R)$ gravity. We take non-static spherically symmetric metric in the interior region and static spherically symmetric metric in the exterior region of a star. The junction conditions between interior and exterior spacetimes are derived. The field equations in f(R) theory are solved using the assumption of constant Ricci scalar. Inserting their solution into junction conditions, the gravitational mass is found. Further, the apparent horizons and their time of formation is discussed. We conclude that the constant scalar curvature term f(R_0) acts as a source of repulsive force and thus slows down the collapse of matter. The comparison with the corresponding results available in general relativity indicates that f(R_0) plays the role of the cosmological constant.