Equilibrium configurations of perfect fluid in Reissner-Nordström-de Sitter spacetimes

Marginally stable perfect fluid tori with uniform distribution of specific angular momentum are determined in the Reissner-Nordström-de Sitter black-hole and naked-singularity spacetimes. Perfect fluid toroidal configurations are allowed only in the spacetimes admitting existence of stable circular geodesics. The configurations with equipotential surfaces crossing itself in a cusp allow accretion (inner cusp) and/or excretion (outer cusp) of matter from the toroidal configuration. The classification of the Reissner-Nordström-de Sitter spacetimes according to the properties of the marginally stable tori is given.