# Ergoregion instability in rotating gravastars

@article{Chirenti2008ErgoregionII, title={Ergoregion instability in rotating gravastars}, author={Cecilia Chirenti and Luciano Rezzolla}, journal={Physical Review D}, year={2008}, volume={78}, pages={084011} }

The ergoregion instability is known to affect very compact objects that rotate very rapidly and do not possess a horizon. We present here a detailed analysis on the relevance of the ergoregion instability for the viability of gravastars. Expanding on some recent results, we show that not all rotating gravastars are unstable. Rather, stable models can be constructed also with J/M{sup 2}{approx}1, where J and M are the angular momentum and mass of the gravastar, respectively. The genesis of…

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## References

SHOWING 1-10 OF 56 REFERENCES

Ergoregion instability of ultracompact astrophysical objects

- Physics
- 2008

Most of the properties of black holes can be mimicked by horizonless compact objects such as gravastars and boson stars. We show that these ultracompact objects develop a strong ergoregion…

On the ergoregion instability

- PhysicsProceedings of the Royal Society of London. A. Mathematical and Physical Sciences
- 1978

Rotating, ultra-compact stars in general relativity can have an ergo-region, in which all trajectories are dragged in the direction of the star’s rotation. The existence of the ergoregion leads to a…

Gravastars must have anisotropic pressures

- Geology
- 2005

One of the very small number of serious alternatives to the usual concept of an astrophysical black hole is the ‘gravastar’ model developed by Mazur and Mottola, and a related phase-transition model…

Stable gravastars—an alternative to black holes?

- Physics
- 2004

The 'gravastar' picture developed by Mazur and Mottola is one of a very small number of serious challenges to our usual conception of a 'black hole'. In the gravastar picture there is effectively a…

Where are all the gravastars? Limits upon the gravastar model from accreting black holes

- Physics
- 2007

The gravastar model, which postulates a strongly correlated thin shell of anisotropic matter surrounding a region of anti-de Sitter space, has been proposed as an alternative to black holes. We…

Gravastars supported by nonlinear electrodynamics

- Physics
- 2007

Gravastar models have recently been proposed as an alternative to black holes, mainly to avoid the problematic issues associated with event horizons and singularities. In this work, a wide variety of…

How to tell a gravastar from a black hole

- Physics
- 2007

Gravastars have been recently proposed as potential alternatives to explain the astrophysical phenomenology traditionally associated with black holes, raising the question of whether the two objects…

Gravastar solutions with continuous pressures and equation of state

- Physics
- 2005

We study the gravitational vacuum star (gravastar) configuration as proposed by Cattoen et al (2005 Class. Quantum Grav. 22 4189) in a model where the interior de Sitter spacetime segment is…

Stable gravastars with generalized exteriors

- Physics
- 2005

New spherically symmetric gravastar solutions, stable to radial perturbations, are found by utilizing the construction of Visser and Wiltshire. The solutions possess an anti-de Sitter or de Sitter…

A new simple model for high-frequency quasi-periodic oscillations in black hole candidates

- Physics
- 2003

Observations of X-ray emissions from binary systems have long since been considered important tools to test general relativity in strong-field regimes. The high-frequency quasi-periodic oscillations…