Circular geodesics of naked singularities in the Kehagias-Sfetsos metric of Horava's gravity

Author(s)

Vieira, Ronaldo S. S. ; Schee, Jan ; Kluzniak, Wlodek ; Stuchlik, Zdenek ; Abramowicz, Marek

• Document type: Journal article
• Source: Physical Review D; v. 90, n. 2, p. 14-pg., 2014-07-14.

Abstract

We discuss photon and test-particle orbits in the Kehagias-Sfetsos (KS) metric of Horava's gravity. For any value of the Horava parameter., there are values of the gravitational mass M for which the metric describes a naked singularity, and this is always accompanied by a vacuum "antigravity sphere" on whose surface a test particle can remain at rest (in a zero angular momentum geodesic), and inside which no circular geodesics exist. The observational appearance of an accreting KS naked singularity in a binary system would be that of a quasistatic spherical fluid shell surrounded by an accretion disk, whose properties depend on the value of M, but are always very different from accretion disks familiar from the Kerr-metric solutions. The properties of the corresponding circular orbits are qualitatively similar to those of the Reissner-Nordstrom naked singularities. When event horizons are present, the orbits outside the Kehagias-Sfetsos black hole are qualitatively similar to those of the Schwarzschild metric. (AU)

• FAPESP's process: 13/01001-0 - A dynamical study of the Eddington capture sphere
• Grantee: Ronaldo Savioli Sumé Vieira
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate