Stability and Horizon Formation during Dissipative Collapse

TL;DR

This paper explores how density inhomogeneities and dissipation influence the collapse of a self-gravitating sphere, revealing effects on stability and horizon formation in a relativistic context.

Contribution

It introduces a perturbative approach to study the impact of anisotropic strings and density fluctuations on collapse dynamics and horizon delay.

Findings

Density inhomogeneities and strings promote instability.

Dissipation delays horizon formation.

Collapse evolves into shear-like regime.

Abstract

We investigate the role played by density inhomogeneities and dissipation on the final outcome of collapse of a self-gravitating sphere. By imposing a perturbative scheme on the thermodynamical variables and gravitational potentials we track the evolution of the collapse process starting off with an initially static perfect fluid sphere which is shear-free. The collapsing core dissipates energy in the form of a radial heat flux with the exterior spacetime being filled with a superposition of null energy and an anisotropic string distribution. The ensuing dynamical process slowly evolves into a shear-like regime with contributions from the heat flux and density fluctuations. We show that the anisotropy due to the presence of the strings drives the stellar fluid towards instability with this effect being enhanced by the density inhomogeneity. An interesting and novel consequence of this collapse scenario is the delay in the formation of the horizon.