A causal model of radiating stellar collapse

Abstract

We find a simple exact model of radiating stellar collapse, with a shear-free and non-accelerating interior matched to a Vaidya exterior. The heat flux is subject to causal thermodynamics, leading to self-consistent determination of the temperature $T$. We solve for $T$ exactly when the mean collision time $τ_{c}$ is constant, and perturbatively in a more realistic case of variable $τ_{c}$. Causal thermodynamics predicts temperature behaviour that can differ significantly from the predictions of non-causal theory. In particular, the causal theory gives a higher central temperature and greater temperature gradient.