Q star

{{Short description|Hypothetical compact star}} {{Distinguish|OpenAI o1{{!}}Q*|quark star}}

thumb|A simple diagram illustrating how some but not all light can escape from a grey hole A '''Q-star''', also known as a '''grey hole''', is a hypothetical type of compact, heavy neutron star with an exotic state of matter. Such a star can be smaller than the progenitor star's Schwarzschild radius and have a gravitational pull so strong that some light, but not all light, can escape.<ref name=":0" /> Light going in the opposite direction of the star’s center would be the most likely to escape from it, while light going in a direction almost parallel to its surface is the most likely not to escape. Light that does escape from this object will likely be gravitationally redshifted. The '''Q''' stands for a conserved particle number. A Q-star may be mistaken for a stellar black hole.<ref>*{{cite journal |doi=10.1046/j.1365-8711.1998.01384.x |title=Are Q-stars a serious threat for stellar-mass black hole candidates? |year=1998 |last1=Miller |first1=J. C. |last2=Shahbaz |first2=T. |last3=Nolan |first3=L. A. |journal=Monthly Notices of the Royal Astronomical Society |volume=294 |issue=2 |pages=L25–L29 |doi-access=free |arxiv=astro-ph/9708065 |bibcode=1998MNRAS.294L..25M }}</ref> Some stellar black holes might be grey holes, two of which are V404 Cygni and Cygnus X-1.<ref name=":0">{{Cite journal|last=Brecher|first=K.|date=1993-05-01|title=Gray Holes|journal=American Astronomical Society Meeting Abstracts #182|volume=182|pages=55.07|bibcode=1993AAS...182.5507B}}</ref>

==Types of Q-stars== *Q-ball<ref name=alex>{{cite conference |conference=workshop on Exotic Physics with Neutrino Telescopes |location=Uppsala, Sweden |bibcode=2006hep.ph...12159K |title=Properties and signatures of supersymmetric Q-balls |last1=Kusenko |first1=Alexander |date=2006 |arxiv=hep-ph/0612159 }}</ref> *B-ball, stable Q-balls with a large baryon number B. They may exist in neutron stars that have absorbed Q-ball(s).<ref name=alex />

==References== {{reflist}}

==Further reading== * {{Cite journal |doi=10.1051/0004-6361:20021645 |title=No observational proof of the black-hole event-horizon |year=2002 |last1=Abramowicz |first1=M. A. |last2=Kluźniak |first2=W. |last3=Lasota |first3=J.-P. |journal=Astronomy & Astrophysics |volume=396 |issue=3 |pages=L31–L34 |arxiv=astro-ph/0207270 |bibcode=2002A&A...396L..31A |s2cid=9771972 }}

Category:Degenerate stars Category:Compact stars Category:Hypothetical stars