Thick accretion disk configurations around a compact object in the brane-world scenario

Abstract

We have studied the equipotential surfaces of a thick accretion disk around a Casadio–Fabbri–Mazzacurati compact object in the brane-world scenario, which possesses a mass parameter together with a parameterized post-Newtonian (PPN) parameter. With the increase in the PPN parameter, the size of the thick accretion disk decreases, but the corresponding Roche lobe size increases. Thus, the larger PPN parameter yields the larger region of existing bound disk structures, where the fluid is not accreted into the central wormhole. Moreover, with the increase in the PPN parameter, the position of the Roche lobe gradually moves away from the central compact object, and the thickness of the region enclosed by the Roche lobe decreases near the compact object but increases in the region far from the compact object. Our results also show that the pressure gradient in the disk decreases with the PPN parameter. These effects of the PPN parameter on the thick accretion disk could help one to further understand compact objects in the brane-world scenario.