Spherical relativistic vacuum core models in a $\Lambda$ Λ -dominated era

Abstract

This paper is devoted to analyzing the effects of the cosmological constant in the evolution of exact analytical collapsing vacuum core celestial models. For this purpose, relativistic spherical geometry coupled with null expansion locally anisotropic matter distributions is considered. We have first developed a relation between tidal forces and structural variables. We then explored some viable spherical cosmological models by taking the expansion-free condition. Our first class of spherical models is obtained after constraining system matter content, while the second class is obtained by considering barotropic equation of state. We propose that our calculated solutions could be regarded as a relativistic toy model for those astronomical compact populations where vacuum core is expected to appear, like cosmological voids.