Dynamics of general barotropic stellar fluid in the framework of R + 2αT gravity

Abstract

Gravitational collapse of a spherically symmetric homogeneous perfect barotropic fluid with linear as well as polytropic-type Equation of State (EoS) has been investigated in the framework of a linear model of [Formula: see text] gravity. This modified gravity has the potential to explain the observed cosmic acceleration. The calculations have been done taking the transformed time coordinate [Formula: see text], where [Formula: see text] is the initial density of the fluid. For linear EoS [Formula: see text], the condition for being a true singularity, along with sufficient condition for the formation of apparent horizon covering the singularity has been derived. For a polytrope having the EoS [Formula: see text], the scale factor [Formula: see text] as a function of fluid density [Formula: see text] has been obtained which is then used to study the dynamics of the fluid. Role of the polytropic index [Formula: see text] and the constant of proportionality [Formula: see text] in the dynamics of the fluid is also studied. A new type of exotic matter field having varied dependence of scale factor on the density, and having the potential to give rise to bouncing cosmology, provided it is the dominating fluid in the universe, is obtained in this domain and is investigated. Energy conditions are discussed.