Null Fluid Collapse in Rastall Theory of Gravity

A Vaidya spacetime is considered for gravitational collapse of a type II fluid in the context of Rastall theory of gravity. For a linear equation of state (EoS) for the fluid profiles, the conditions under which the dynamical evolution of the collapse can give rise to the formation of a naked singularity are examined. It is shown that depending on the model parameters, strong-curvature naked singularities would arise as exact solutions to the Rastall's field equations. The allowed values of these parameters satisfy certain conditions on the physical reliability, nakedness and the curvature strength of the singularity. It turns out that Rastall gravity, in comparison to general relativity (GR), provides a wider class of physically reasonable spacetimes that admit both locally and globally naked singularities.