Isotropic and Anisotropic Radiating Gravastars with Various Matter Types of Thin Shell and Interior

Abstract: In this paper, we investigate models of radiating gravastars with both isotropic and anisotropic interiors, incorporating various types of thin shell matter. For the isotropic interior case, we consider a thin spherical shell characterized by an equation of state in which its pressure is proportional to its mass density, enclosing a de Sitter spacetime and surrounded by Vaidya exterior spacetime. Our analysis reveals that stable gravastars can form under specific scenarios of radiative mechanisms and for certain thin shell matter types. In addition, we also show and discuss in brief the possibility of existence of stable radiating anti-de Sitter gravastar formation. For the anisotropic interior, we use an anisotropic dark energy model with a Tolman-Matese-Whitman (TMW) mass function. We explore several thin shell matter types: standard, dark energy, and repulsive phantom. Our findings indicate that stable gravastars can also emerge in this context, particularly with standard and repulsive phantom thin shells. Furthermore, our results suggest that the density of black holes is consistently higher than that of gravastars and normal stars, regardless of the type of matter in the thin shell. This observation supports the notion that gravastars and black holes are distinct entities, reinforcing the theoretical distinction between these two types of compact objects.