Abstract
We consider the dynamics of particles, particularly focusing on circular orbits in the higher-dimensional Majumdar-Papapetrou (MP) spacetimes with two equal mass black holes. It is widely known that in the 5D Schwarzschild-Tangherlini and Myers-Perry backgrounds, there are no stable circular orbits. In contrast, we show that in the 5D MP background, stable circular orbits can always exist when the separation of two black holes is large enough. More precisely, for a large separation, stable circular orbits exist from the vicinity of horizons to infinity; for a medium one, they appear only in a certain finite region bounded by the innermost stable circular orbit and the outermost stable circular orbit outside the horizons; for a small one, they do not appear at all. Moreover, we show that in MP spacetimes in more than 5D, they do not exist for any separations.
Highlights
The dynamics of test free particles in curved spacetimes, i.e., the geodesic structure, include important information about the gravitational field and the geometry
We have considered the dynamics of particles, focusing on circular orbits, in the d-dimensional MP dihole spacetime (d ≥ 5)
Using the on-shell conditions for geodesic motion, we have clarified the conditions for the existence of circular orbits in terms of a 2D effective potential and have provided a prescription for determining whether these orbits are stable
Summary
The dynamics of test free particles in curved spacetimes, i.e., the geodesic structure, include important information about the gravitational field and the geometry. There exist the innermost stable circular orbit (ISCO) at their boundary r 1⁄4 6M and the unstable photon circular orbit at the last circular orbit r 1⁄4 3M These are fundamentals of physical phenomena in the vicinity of a black hole. The parametrization allows us to distinguish between d-dependent/ independent properties and tells us some special properties in a specific d Such dimensionality often appears in the analysis of gravitational properties through geodesic structure, which is the first step in the study of black holes. Unlike the 4D case, in a higher-dimensional static and spherically symmetric vacuum black hole, there is no stable circular orbit because no stable balance is formed between the gravitational and centrifugal forces [3], which is a generic feature of higher-dimensional black holes with a spherically symmetric horizon [4]. As one of the rich properties of higher-dimensional spacetimes, there is the topological variety of spatial cross
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
