Publication date: Aug 2011
Abstract:
String theory predicts the existence of extremely compact objects
spinning faster than Kerr black holes. The spacetime exterior to such
superspinars is described by Kerr naked singularity geometry breaking
the black-hole limit on the internal angular momentum. We demonstrate
that the conversion of Kerr superspinars into a near-extreme black hole
due to an accretion counterrotating Keplerian disc is much more
effective in comparison with the case of a corotating one since both the
accreted rest mass necessary for conversion and the evolution time of
conversion are by orders smaller for counterrotating discs. The
conversion time of Kerr superspinars is given for several accretion
regimes, and it is shown that the self-regulated accretion flow implies
fastest evolution to the black-hole state. In the final stages of the
conversion, Kerr superspinars can serve as very efficient particle
accelerators in the region where the black-hole horizon forms.
Authors:
Stuchlík, Zdeněk; Hledík, Stanislav; Truparová, Kamila;