Spherical doubly warped spacetimes for radiating stars and cosmology

Abstract Spherically symmetric spacetimes are ambient spaces for models of stellar collapse and inhomogeneous cosmology. We obtain results the Weyl tensor covariant form Ricci on general doubly warped (DW) spacetimes. In a spherically metric, electric tensors become rank-2, built with metric tensor, velocity vector field its acceleration. Their structure dictates energy-momentum in Einstein equations DW spherical metrics. The anisotropic pressure heat current an imperfect fluid descend from gradient acceleration part tensor. For radiating flow, junction conditions Vaidya reviewed, boundary condition radial pressure. isotropy simply accomodate various literature. anisotropy special case GRW space-times (geodesic velocity), gives Friedmann deviating standard FRW cosmology by terms due to introduce “perfect 2-scalars” discuss f ( R ) gravity source spacetime, show that new geometric do not change