Regular Article - Theoretical Physics
Fundamental photon orbits in the double Schwarzschild space-time
Department of Physics, National University of Singapore, Singapore, Singapore
Accepted: 2 November 2022
Published online: 11 November 2022
We consider photon orbits in the space-time consisting of two identical Schwarzschild black holes in static equilibrium. In particular, we focus on fundamental photon orbits – bound photon orbits that do not fall into either black hole or go to infinity. It is known that there could exist up to two circular photon orbits lying in the plane of symmetry between the black holes. In this paper, we present more examples of fundamental photon orbits in this space-time. This includes non-circular orbits lying in the plane of symmetry, circular orbits that lie off the plane of symmetry, polar orbits, and non-planar orbits that orbit around one or both of the black holes. These orbits are all unstable. Finally, in an appendix, we present a class of circular time-like orbits that lie off the plane of symmetry.
© The Author(s) 2022
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Funded by SCOAP3. SCOAP3 supports the goals of the International Year of Basic Sciences for Sustainable Development.