Precession of timelike bound orbits in Kerr spacetime

TL;DR

This paper investigates the precession of bound timelike orbits in Kerr spacetime and finds that negative precession, unlike in naked singularity spacetimes, does not occur for low eccentric equatorial orbits around a rotating black hole.

Contribution

It provides an analysis of perihelion precession in Kerr spacetime, demonstrating the absence of negative precession for low eccentric bound orbits.

Findings

Negative precession is not allowed in Kerr spacetime for studied orbits.

The study focuses on low eccentricity equatorial orbits around a Kerr black hole.

Results contrast with naked singularity spacetimes where negative precession can occur.

Abstract

Astrometric observations of S-stars provide a unique opportunity to probe the nature of Sagittarius-A* (Sgr-A*). In view of this, it has become important to understand the nature and behavior of timelike bound trajectories of particles around a massive central object. It is known now that whereas the Schwarzschild black hole does not allow the negative precession for the S-stars, the naked singularity spacetimes can admit the positive as well as negative precession for the bound timelike orbits. In this context, we study the perihelion precession of a test particle in the Kerr spacetime geometry. Considering some approximations, we investigate whether the timelike bound orbits of a test particle in Kerr spacetime can have negative precession. In this paper, we only consider low eccentric timelike equatorial orbits. With these considerations, we find that in Kerr spacetimes, negative precession of timelike bound orbits is not allowed.