Q Type Star

A Q Star, also a grey hole, is a hypothetical neutron star. It contains a strange matter. It would have a gravitational pull so strong that some light, but not all photons can escape.

A Q-star may be mistaken for a stellar black hole.^[1]

References

↑ *Miller, J. C.; Shahbaz, T.; Nolan, L. A. (1998). "Are Q-stars a serious threat for stellar-mass black hole candidates?". Monthly Notices of the Royal Astronomical Society. 294 (2): L25 – L29. arXiv:astro-ph/9708065. Bibcode:1998MNRAS.294L..25M. doi:10.1046/j.1365-8711.1998.01384.x.

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[1] *Miller, J. C.; Shahbaz, T.; Nolan, L. A. (1998). "Are Q-stars a serious threat for stellar-mass black hole candidates?". Monthly Notices of the Royal Astronomical Society. 294 (2): L25 – L29. arXiv:astro-ph/9708065. Bibcode:1998MNRAS.294L..25M. doi:10.1046/j.1365-8711.1998.01384.x.

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v t e Black holes
Types	Schwarzschild Rotating Supermassive Primordial BTZ black hole Charged Virtual Kugelblitz Direct collapse Rogue Malament–Hogarth spacetime
Size	Micro Extremal Electron Hawking star Stellar Microquasar Supermassive Active galactic nucleus Quasar LQG Blazar OVV Radio-Quiet Radio-Loud Intermediate-mass
Formation	Stellar evolution Gravitational collapse Neutron star White dwarf Supernova Micronova Hypernova Gamma-ray burst Binary black hole Quasi-star Tolman–Oppenheimer–Volkoff limit Quark star Supermassive star Supermassive dark star X-ray binary
Properties	Gravitational singularity Ring singularity Theorems Event horizon Ergosphere Penrose process Blandford–Znajek process Accretion disk Hawking radiation Gravitational lens Microlens Schwarzschild radius Spaghettification Astrophysical jet Photon sphere Innermost stable circular orbit Bondi accretion M–sigma relation Quasi-periodic oscillation Thermodynamics Bekenstein bound Bousso's holographic bound Immirzi parameter
Issues	Information paradox Final parsec problem Holographic principle No-hair theorem Black hole complementarity Cosmic censorship ER = EPR Firewall (physics)
Metrics	Schwarzschild (Derivation) Kerr Reissner–Nordström Kerr–Newman Hayward
Alternatives	Nonsingular black hole models Black star Dark star Dark-energy star Gravastar Magnetospheric eternally collapsing object Planck star Q star Fuzzball
Analogs	Optical black hole Sonic black hole
Related	Outline of black holes Black Hole Initiative Black hole starship Big Bang Big Bounce Compact star Exotic star Quark star Preon star Gravitational waves Gamma-ray burst progenitors Gravity well Hypercompact stellar system Membrane paradigm Naked singularity Population III star Supermassive star Quasi-star Supermassive dark star Rossi X-ray Timing Explorer Superluminal motion Timeline of black hole physics White hole Wormhole Tidal disruption event Planet Nine
Notable	Cygnus X-1 Sagittarius A* Centaurus A MS 0735.6+7421 XTE J1650-500 XTE J1118+480 A0620-00 SDSS J150243.09+111557.3 Phoenix Cluster PKS 1302-102 OJ 287 SDSS J0849+1114 TON 618 NeVe 1 Hercules A 3C 273 Q0906+6930 Markarian 501 ULAS J1342+0928 PSO J030947.49+271757.31 P172+18