Gravastars as Nontopological Solitons

Abstract: We investigate a coupled system consisting of a complex scalar field, a U(1) gauge field, a complex Higgs scalar field, and Einstein gravity. We present nontopological soliton star solutions in which the interior geometry is described by the de Sitter metric, the exterior by the Schwarzschild metric, and these two regions are attached by a spherical surface layer with a finite thickness. This structure is the same as the so-called gravastars, so we refer to these solutions as \lq solitonic gravastars\rq . We demonstrate that compact solitonic gravastars that possessing photon spheres can appear. Additionally, we study the mass and compactness of solitonic gravastars for various sets of parameters that characterize the system.