Dubravko Horvat, Saša Ilijic, Anja Marunovic (Zagreb):

Charged Gravastar

Abstract:

The notion of a compact object immune of the horizon problem and comprising of an anisotropic inhomogenous fluid with specific radial pressure behavior, i.e. the gravastar, is extended by introducing an electric charged component. Einstein field equations are solved together with Einstein-Maxwell equation, where source of the electric field is tied to the fluid energy density. The coupled nonlinear problem is solved at different levels of complexity and sophistication with the aim to show that solutions which bear all the features of the gravastar could be find in situations where conditions for their existence are being pushed to their limit. In the analisys of the obtained results it is shown that the charged component of the total gravastar configuration has to be mixed with caution since the sensitive condition for the absence of the horizon could be violated. Also, the charged configuration is shown to belong to large class of solutions which in certain limit could reach the stage of quasi black holes.