Heat flow in the postquasistatic approximation

TL;DR

This paper uses the postquasistatic approximation to analyze the evolution of spherically symmetric, dissipative fluid distributions, revealing limitations on collapse and the effects of energy emission on different models.

Contribution

It applies the postquasistatic approximation to model dissipative fluid evolution, highlighting constraints on collapse and the role of energy emission in avoiding collapse.

Findings

Incompressible fluid models cannot deviate far from initial state after small energy emission.

Initially collapsing distributions are not permitted in the model.

Outer layers of highly compressed Fermi gas models evolve with shorter hydrodynamic timescales.

Abstract

We apply the postquasistatic approximation to study the evolution of spherically symmetric fluid distributions undergoing dissipation in the form of radial heat flow. For a model which corresponds to an incompressible fluid departing from the static equilibrium, it is not possible to go far from the initial state after the emission of a small amount of energy. Initially collapsing distributions of matter are not permitted. Emission of energy can be considered as a mechanism to avoid the collapse. If the distribution collapses initially and emits one hundredth of the initial mass only the outermost layers evolve. For a model which corresponds to a highly compressed Fermi gas, only the outermost shell can evolve with a shorter hydrodynamic time scale.