A stellar model with diffusion in general relativity
Artikel i vetenskaplig tidskrift, 2017

We consider a spherically symmetric stellar model in general relativity whose interior consists of a pressureless fluid undergoing microscopic velocity diffusion in a cosmological scalar field. We show that the diffusion dynamics compel the interior to be spatially homogeneous, by which one can infer immediately that within our model, and in contrast to the diffusion-free case, no naked singularities can form in the gravitational collapse. We then study the problem of matching an exterior Bondi type metric to the surface of the star and find that the exterior can be chosen to be a modified Vaidya metric with variable cosmological constant. Finally, we study in detail the causal structure of an explicit, self similar solution.


General relativity

Gravitational collapse



Artur Alho

Instituto Superior Tecnico

Simone Calogero

Göteborgs universitet

Chalmers, Matematiska vetenskaper, Analys och sannolikhetsteori

Journal of Geometry and Physics

0393-0440 (ISSN)

Vol. 120 62-72