Timelike orbits around accelerating black holes

TL;DR

This paper analyzes the geodesics of particles around accelerating Schwarzschild black holes, revealing how acceleration influences stable orbits, introduces a repulsive effect, and affects perihelion precession, with implications across different cosmological backgrounds.

Contribution

It provides a detailed study of particle orbits around accelerating black holes, highlighting qualitative changes due to acceleration and the existence of an outermost stable orbit in various backgrounds.

Findings

Innermost stable circular orbit radius increases with acceleration.

Acceleration acts as a repulsive force affecting radial motion.

Precession of perihelion is larger and can be opposite in anti de Sitter backgrounds.

Abstract

We study the geodesics of massive particles around accelerating Schwarzschild black hole. We show that the radius of the innermost stable circular orbit increases and the angular momentum of particle at this orbit decreases by increasing the acceleration. Apart from quantitative influence, the acceleration qualitatively changes the physics. We show that in accelerating black hole spacetime there exist an outermost stable circular orbit in flat, de Sitter, and anti de Sitter background. Investigations of radial geodesics show that the acceleration acts like a repulsive force in the sense that test particles around accelerating black holes can move radially outward, unless there exist a large negative value of cosmological constant in the background to compensate the repulsive force. We also investigate the precession of perihelion of orbits around accelerating black holes. The precession would be larger compared to the non-accelerating case. It is also shown that the precession in anti de Sitter background could be opposite to the particle motion.