Study of rotating gravastars

Abstract

In this work, we have discussed about a rotating gravastar model and some physical aspects in the presence of an anisotropic fluid source in the framework of General Relativity. We have considered two cases: one is gravastar’s interior fluid rigidly (or slowly) rotates, and the other is gravastar’s interior fluid non-rigidly rotates. We have considered a gravastar with three regions: interior region, thin shell region, and exterior region. We have written the field equations for a spherically symmetric object in which interior fluid rigidly (or slowly) rotates with angular velocity ([Formula: see text]). Next, we have solved the field equations in three regions of a gravastar. To compute the analytical solution within the shell region, we have used the approximation [Formula: see text]. Some physical quantities, like the proper length of the thin shell, energy, and entropy within the shell, have been obtained and discussed graphically. We have evaluated the surface energy density and the surface pressure analytically through the junction conditions between the surfaces of the interior and exterior regions. Next, we have discussed the equation of state parameter of the surface layer, the mass of the thin shell, and the total mass of the gravastar analytically and graphically. Also, we have discussed the stable region of such type gravastar. Again, we constructed the field equations for a spherically symmetric object in which interior fluid rotates non-rigidly. Next, we have discussed these field equations for a gravastar with three regions. Also, we have obtained some physical quantities like the proper length of the thin shell region, energy, entropy, density and angular velocity within the shell region for such type of gravastar. The stability has been discussed through the surface redshift within the shell region, and we get our model stable and physically valid.