J 2005

Aschenbach effect: Unexpected topology changes in the motion of particles and fluids orbiting rapidly rotating Kerr black holes

STUCHLÍK, Zdeněk, Petr SLANÝ, Gabriel TÖRÖK and Marek ABRAMOWICZ

Basic information

Original name

Aschenbach effect: Unexpected topology changes in the motion of particles and fluids orbiting rapidly rotating Kerr black holes

Authors

STUCHLÍK, Zdeněk, Petr SLANÝ, Gabriel TÖRÖK and Marek ABRAMOWICZ

Edition

Physical Review D, COLLEGE PK, AMER PHYSICAL SOC, 2005, 1550-7998

Other information

Language

English

Type of outcome

Článek v odborném periodiku

Confidentiality degree

není předmětem státního či obchodního tajemství

Organization unit

Faculty of Philosophy and Science in Opava

DOI

http://dx.doi.org/10.1103/PhysRevD.71.024037

UT WoS

000226702700075

Tags

clanek, GACR202020735, GACR20503H144, Torokcentrum

Tags

International impact, Reviewed
Změněno: 12/4/2021 14:15, RNDr. Kateřina Klimovičová, Ph.D.

Abstract

V originále

Newtonian theory predicts that the velocity V of free test particles on circular orbits around a spherical gravity center is a decreasing function of the orbital radius r, dV/dr<0. Only very recently, Aschenbach [B. Aschenbach, Astronomy and Astrophysics, 425, 1075 (2004)] has shown that, unexpectedly, the same is not true for particles orbiting black holes: for Kerr black holes with the spin parameter a>0.9953, the velocity has a positive radial gradient for geodesic, stable, circular orbits in a small radial range close to the black-hole horizon. We show here that the Aschenbach effect occurs also for nongeodesic circular orbits with constant specific angular momentum l=l(0)=const. In Newtonian theory it is V=l(0)/R, with R being the cylindrical radius. The equivelocity surfaces coincide with the R=const surfaces which, of course, are just coaxial cylinders. It was previously known that in the black-hole case this simple topology changes because one of the "cylinders" self-crosses. The results indicate that the Aschenbach effect is connected to a second topology change that for the l=const tori occurs only for very highly spinning black holes, a>0.99979.
Displayed: 25/11/2024 16:54