Pith. sign in

REVIEW 19 cited by

Exotic Compact Objects and the Fate of the Light-Ring Instability

Not yet reviewed by Pith; the record is open.

This paper has not been read by Pith yet. Machine review is queued; the pith claim, tier, and objections will appear here once it completes.

SPECIMEN: schema-true, not a live event

T0 review · schema-true

One-sentence machine reading of the paper's core claim.

pith:XXXXXXXX · record.json · timestamp

arxiv 2207.13713 v2 pith:7CHBSEV7 submitted 2022-07-27 gr-qc astro-ph.HEhep-th

Exotic Compact Objects and the Fate of the Light-Ring Instability

classification gr-qc astro-ph.HEhep-th
keywords objectsinstabilityultracompactbeencollapseeffectivefatemigration
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved
0 comments
read the original abstract

Ultracompact objects with light-rings (LRs) but without an event horizon could mimic black holes (BHs) in their strong gravity phenomenology. But are such objects dynamically viable? Stationary and axisymmetric ultracompact objects that can form from smooth, quasi-Minkowski initial data must have at least one stable LR, which has been argued to trigger a spacetime instability; but its development and fate have been unknown. Using fully non-linear numerical evolutions of ultracompact bosonic stars free of any other known instabilities and introducing a novel adiabatic effective potential technique, we confirm the LRs triggered instability, identifying two possible fates: migration to non-ultracompact configurations or collapse to BHs. In concrete examples we show that typical migration/collapse time scales are not larger than $\sim 10^3$ light-crossing times, unless the stable LR potential well is very shallow. Our results show that the LR instability is effective in destroying horizonless ultracompact objects that could be plausible BH imitators.

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Forward citations

Cited by 19 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. Boson Stars in $D \ge 4$ Dimensions: Stability, Oscillation Frequencies, and Dynamical Evolutions

    gr-qc 2025-10 conditional novelty 9.0

    Self-interacting boson stars in D=5,6 and solitonic boson stars in D=5 can be radially stable, as shown by generalized pulsation equations and nonlinear spherical evolutions.

  2. Photon spheres in dynamical space-times

    gr-qc 2026-06 unverdicted novelty 7.0

    A covariant framework is developed for photon surfaces in dynamical spherical spacetimes, recovering static limits and applied to collapse and accretion/evaporation models.

  3. Axial Oscillations of Viscous Neutron Stars

    gr-qc 2026-04 unverdicted novelty 7.0

    Viscous neutron stars have new families of axial oscillation modes without perfect-fluid counterparts, featuring mode avoidance and long-lived modes.

  4. Weakly turbulent saturation of the nonlinear scalar ergoregion instability

    gr-qc 2025-10 unverdicted novelty 7.0

    Time-domain evolutions demonstrate that the nonlinear scalar ergoregion instability saturates via a weakly turbulent direct cascade transferring energy to small scales and populating higher-order azimuthal modes on th...

  5. Topological charge and black hole photon spheres in massive gravity

    gr-qc 2025-09 unverdicted novelty 7.0

    In dRGT massive gravity, static spherically symmetric black holes exhibit zero, one, or two photon spheres whose topological charges and stability patterns differ from Einstein gravity and from horizonless compact objects.

  6. On Black Holes Surrounded by Radiation: I. Classical Considerations

    hep-th 2026-06 unverdicted novelty 6.0

    Presents classical GR solutions for black holes enveloped by ultra-relativistic orbiting particle shells that extend the photon sphere to arbitrary depth while remaining optically indistinguishable from standard black holes.

  7. Neutron stars more compact than black holes in quasi-topological gravity: Equilibrium configurations and radial stability

    gr-qc 2026-05 conditional novelty 6.0

    Neutron stars in quasi-topological gravity can be more compact than black holes and radially stable across several equations of state.

  8. Axial Oscillations of Viscous Neutron Stars

    gr-qc 2026-04 unverdicted novelty 6.0

    Causal viscous relativistic hydrodynamics applied to neutron stars yields new axial mode families without perfect-fluid counterparts, including mode avoidance and long-lived modes.

  9. Light rings, gravitational lensing, and ISCOs of exotic compact objects in Einstein-scalar-Maxwell theories

    gr-qc 2026-02 conditional novelty 6.0

    A new family of shell-like, charged, horizonless compact objects is constructed in Einstein-scalar-Maxwell theory, with photon-ring, lensing, and ISCO predictions.

  10. A Universal Framework for Horizon-Scale Tests of Gravity with Black Hole Shadows

    gr-qc 2025-11 conditional novelty 6.0

    An adaptive ray-tracing and MCMC framework estimates shadow observables for arbitrary stationary metrics; applied to the Kerr–Bertotti–Robinson spacetime it yields an Sgr A* horizon-scale magnetic field of about 93 G ...

  11. As Cold as a Black Hole: Extended Photon Spheres

    hep-th 2026-06 unverdicted novelty 5.0

    A necessary and sufficient condition for thermodynamic mimicry of Schwarzschild black holes is satisfied by a one-parameter family of self-similar systems including hillingar black holes, stiffest stars, and frozen st...

  12. Neutron stars more compact than black holes in quasi-topological gravity: Equilibrium configurations and radial stability

    gr-qc 2026-05 unverdicted novelty 5.0

    In quasi-topological gravity, neutron stars can surpass black-hole compactness with universal high-density behavior and theory corrections that stabilize radially unstable configurations from general relativity.

  13. Echoes of a hairy black hole from gravitational decoupling

    gr-qc 2026-04 conditional novelty 5.0

    Axial perturbations of a gravitationally decoupled hairy black hole develop a double-peak potential that dynamically generates echo-like late-time waveforms in a suitable (α, β) region.

  14. Echoes of a hairy black hole from gravitational decoupling

    gr-qc 2026-04 unverdicted novelty 5.0

    Axial perturbations around a hairy black hole from gravitational decoupling produce echo-like gravitational-wave signals that arise dynamically from a double-peak trapping cavity in the effective potential.

  15. Shadow signatures and energy accumulation in Lorentzian-Euclidean black holes

    gr-qc 2026-01 unverdicted novelty 5.0

    Lorentzian-Euclidean black holes produce excess inner-shadow intensity and accumulate energy at the horizon with backreaction unlike stable light rings.

  16. Matter environments around black holes: geodesics, light rings, and ultracompact configurations

    gr-qc 2025-12 conditional novelty 5.0

    Dark-matter halos modeled as Einstein clusters generically move the ISCO inward and the light ring outward, and ultracompact halos can add extra light rings, trapped modes, and secondary horizons.

  17. AdS gravastar and its signatures from dual conformal field theory

    hep-th 2025-12 unverdicted novelty 5.0

    AdS gravastar glued from AdS-Schwarzschild and de Sitter yields horizon-less signatures including specific bulk-cone singularities and echoes in dual CFT retarded Green functions.

  18. Search for growing angular modes in ultracompact boson star evolutions

    gr-qc 2025-08 unverdicted novelty 4.0

    The paper decomposes simulation data of ultracompact boson stars into spherical harmonics as a first step toward characterizing non-spherical modes.

  19. Dynamical Boson Stars

    gr-qc 2012-02 unverdicted novelty 2.0

    Boson stars are particle-like solutions in general relativity that model dark matter, black hole mimickers, and binary systems.