Circular orbits and accretion process in a class of Horndeski/Galileon black holes

TL;DR

This paper explores the motion of particles and accretion processes around a specific class of Horndeski/Galileon black holes, analyzing stability, oscillations, and flow rates in these exotic spacetimes.

Contribution

It provides a detailed analysis of geodesic motion, stability of circular orbits, and accretion dynamics in a subclass of Horndeski/Galileon black hole spacetimes, which is a novel investigation.

Findings

Stable circular orbits identified in the spacetime.

Oscillation frequencies of particles around the black hole calculated.

Critical accretion speeds and rates determined for the model.

Abstract

In this paper the geodesics motion and accretion process around a subclass of Horndeski/Galileon black holes are investigated. Firstly, we present spherically symmetric geometries in a Horndeski/Galileon black hole spacetime by considering an isothermal fluid around the black hole. Then we focus on three main issues: in the first step circular orbits of test particles and their stability in equatorial plane are examined in details. Then, by treating perturbations via restoring forces, oscillations of particles around the central object are studied. Finally, the accretion process, the critical speed of the flow and accretion rate are investigated in this setup properly.