Periodic orbits around Kerr Sen black holes

TL;DR

This paper studies the properties of periodic orbits and zoom-whirl behaviors around Kerr Sen black holes, highlighting how charge influences orbit characteristics and energy requirements compared to Kerr black holes.

Contribution

It introduces a new analysis of periodic orbits in Kerr Sen black holes using rational parameters, extending understanding of zoom-whirl behaviors in strong gravitational fields.

Findings

Zoom-whirl orbits exhibit precession similar to Kerr black holes.

Lower energies are needed for similar orbits in Kerr Sen black holes.

Charge parameter $b$ significantly affects orbit dynamics.

Abstract

We investigate periodic orbits and zoom-whirl behaviors around a Kerr Sen black hole with a rational number $q$ in terms of three integers $(z,w,v)$, from which one can immediately read off the number of leaves(or zooms), the ordering of the leaves, and the number of whirls. The characteristic of zoom-whirl periodic orbits is the precession of multi-leaf orbits in the strong field regime. This feature is analogous to the counterpart in the Kerr space-time. Finally, we analyze the impact of the charge parameter $b$ on the zoom-whirl periodic orbits. Compared to the periodic orbits around the Kerr black hole, it is found that typically lower energies are required for the same orbits in the Kerr Sen black hole.