Dynamics of viscous dissipative gravitational collapse: A full causal approach

TL;DR

This paper extends the Misner-Sharp approach to viscous dissipative gravitational collapse using a full causal framework, incorporating heat flux, shear, and bulk viscosity with causal transport equations, and compares it with previous non-causal models.

Contribution

It introduces a full causal treatment of viscous dissipative gravitational collapse, including thermodynamic viscous/heat coupling, which was not considered in earlier models.

Findings

Derived coupled dynamical and causal transport equations for viscous collapse.

Compared causal and non-causal models, highlighting differences.

Discussed potential astrophysical applications of the causal approach.

Abstract

The Misner and Sharp approach to the study of gravitational collapse is extended to the viscous dissipative case in, both, the streaming out and the diffusion approximations. The dynamical equation is then coupled to causal transport equations for the heat flux, the shear and the bulk viscosity, in the context of Israel--Stewart theory, without excluding the thermodynamics viscous/heat coupling coefficients. The result is compared with previous works where these later coefficients were neglected and viscosity variables were not assumed to satisfy causal transport equations. Prospective applications of this result to some astrophysical scenarios are discussed.