Publication date: Sep 2015
Abstract:
We construct perfect fluid tori in the field of the Kehagias-Sfetsos
(K-S) naked singularities. These are spherically symmetric vacuum
solutions of the modified Hořava quantum gravity, characterized
by a dimensionless parameter ω M^2, combining the gravitational
mass parameter M of the spacetime with the Hořava parameter
ω reflecting the role of the quantum corrections. In dependence on
the value of ω M^2, the K-S naked singularities demonstrate a
variety of qualitatively different behavior of their circular geodesics
that is fully reflected in the properties of the toroidal structures,
demonstrating clear distinction to the properties of the torii in the
Schwarzschild spacetimes. In all of the K-S naked singularity spacetimes
the tori are located above an "antigravity" sphere where matter can stay
in a stable equilibrium position, which is relevant for the stability of
the orbiting fluid toroidal accretion structures. The signature of the
K-S naked singularity is given by the properties of marginally stable
tori orbiting with the uniform distribution of the specific angular
momentum of the fluid, l= const. In the K-S naked singularity spacetimes
with ω M^2 > 0.2811, doubled tori with the same l= const can
exist; mass transfer between the outer torus and the inner one is
possible under appropriate conditions, while only outflow to the outer
space is allowed in complementary conditions. In the K-S spacetimes with
ω M^2 < 0.2811, accretion from cusped perfect fluid tori is not
possible due to the non-existence of unstable circular geodesics.
Authors:
Stuchlík, Z.; Pugliese, D.; Schee, J.; Kučáková, H.;