2019/01/31 by Yan Peng
Mathematics · Physics and Astronomy · #Angular momentum #Astrophysical Phenomena and Observations #Astrophysics #Axial symmetry #Black Holes and Theoretical Physics #Black hole (networking) #Circular orbit #Classical mechanics #Fermat's Last Theorem #Geodesic #Geometry #Mathematical physics #Mathematics #Null (SQL) #Orbital period #Physics #Pulsars and Gravitational Waves Research #Pure mathematics #Quantum mechanics #Rotating black hole #Scalar field #Spacetime #Theoretical physics #gr-qc #hep-ph #hep-th
paper · pdf · doi:10.1016/j.physletb.2019.03.022
published as Physics Letters B 792(2019)1-3 · 7 pages
openalex publication_date 2019/03/14 · arxiv created 2019/03/16 · arxiv updated 2019/03/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
In a very interesting paper, Hod has proven that the equatorial null circular geodesic provides the extreme orbital period to circle a kerr black hole, which is closely related to the Fermat's principle. In the present paper, we extend the discussion to kerr black holes with scalar field hair. We show that the circle with the extreme orbital period is still identical to the null circular geodesic. Our analysis also implies that the Hod's theorem may be a general property in any axially symmetric spacetime with reflection symmetry on the equatorial plane.