LogoLogo
  • Bio
  • Fyzika
  • V médiích
  • Fotografie
  • Výstavy
  • Kontakt

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

    Zdeněk Stuchlík · 01 ledna, 2005 · Fyzika · 0 comments
    0

    Publication date: Jan 2005

    Abstract:
    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=ℓ0=const. In Newtonian theory it is
    V=ℓ0/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.

    Authors:
    Stuchlík, Zdeněk; Slaný, Petr; Török, Gabriel; Abramowicz, Marek A.;

    http://adsabs.harvard.edu/abs/2005PhRvD..71b4037S

      Facebook   Pinterest   Twitter

    Leave a Comment! Zrušit odpověď na komentář

    You must be logged in to post a comment.
    Archivy
    Copyright © 2024 Zdeněk Stuchlík