Mass Gap Solutions from Vacuum Energy in Compact Stars

The primary objective of this study is to investigate the impact of vacuum energy on the mass-radius relation, stability criteria and other essential physical properties of charged anisotropic compact stars. We consider the coexistence of ordinary matter and vacuum energy within the stellar core. The normal matter component is modeled using the MIT bag model equation of state, while the vacuum energy is assumed to obey the standard equation of state, [Formula: see text]. The relative contribution of matter to the total energy density is characterized by the dimensionless parameter [Formula: see text] where [Formula: see text] denotes the fractional matter energy density. Our analysis reveals that the presence of vacuum energy enhances the pressure anisotropy within the stellar interior. Notably, the obtained solutions support the existence of massive neutron stars within the mass gap [Formula: see text].