**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.;