Study of gravastar admitting Tolman IV spacetime in Rastall theory

In this paper, we present a novel solution representing the gravastar (or gravitational vacuum star) model within the framework of non-conservative Rastall gravity. As a viable alternative to black holes, the geometry of a gravastar comprises three distinct regions: the inner sector, the intermediate layer, and the exterior domain. Utilizing the temporal component of Tolman IV spacetime, we derive the singularity-free radial metric potentials for both the inner and intermediate regions. Further, by aligning the thin shell with the external Schwarzschild line element, we establish boundary conditions in order to determine unknown constants that appear due to the chosen ansatz and performing some integrations. Subsequently, we investigate various properties for the gravastar’s shell, including the equation of state parameter, proper length, energy, entropy and gravitational redshift for four different values of the Rastall parameter. It is concluded that the gravastar structure exists and provides a feasible substitute of black holes in the framework of Rastall theory.