Superspinars are ultracompact objects whose mass M and angular momentum J violate the Kerr bound (cJ/GM2>1). Recent studies analyzed the observable consequences of gravitational lensing and accretion around superspinars in astrophysical scenarios. In this paper we investigate the dynamical stability of superspinars to gravitational perturbations, considering either purely reflecting or perfectly absorbing boundary conditions at the “surface” of the superspinar. We find that these objects are unstable independently of the boundary conditions, and that the instability is strongest for relatively small values of the spin. Also, we give a physical interpretation of the various instabilities that we find. Our results (together with the well-known fact that accretion tends to spin superspinars down) imply that superspinars are very unlikely astrophysical alternatives to black holes.

Gravitational instabilities of superspinars / Pani, P; Barausse, E; Berti, E; Cardoso, V. - In: PHYSICAL REVIEW D, PARTICLES, FIELDS, GRAVITATION, AND COSMOLOGY. - ISSN 1550-7998. - 82:4(2010), pp. 1-15. [10.1103/PhysRevD.82.044009]

Gravitational instabilities of superspinars

Barausse E;
2010

Abstract

Superspinars are ultracompact objects whose mass M and angular momentum J violate the Kerr bound (cJ/GM2>1). Recent studies analyzed the observable consequences of gravitational lensing and accretion around superspinars in astrophysical scenarios. In this paper we investigate the dynamical stability of superspinars to gravitational perturbations, considering either purely reflecting or perfectly absorbing boundary conditions at the “surface” of the superspinar. We find that these objects are unstable independently of the boundary conditions, and that the instability is strongest for relatively small values of the spin. Also, we give a physical interpretation of the various instabilities that we find. Our results (together with the well-known fact that accretion tends to spin superspinars down) imply that superspinars are very unlikely astrophysical alternatives to black holes.
82
4
1
15
044009
http://link.aps.org/doi/10.1103/PhysRevD.82.044009
https://arxiv.org/abs/1006.1863
Pani, P; Barausse, E; Berti, E; Cardoso, V
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/89718
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 79
  • ???jsp.display-item.citation.isi??? 75
social impact