collapsar

{{Short description|Star that has undergone gravitational collapse}}

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File:Collapsar as initial mass-metallicity.svg

A collapsar (a portmanteau word formed by "collapsed" + "star") is a star which has undergone gravitational collapse.{{Cite web |title=COLLAPSAR {{!}} Meaning & Definition for UK English {{!}} Lexico.com |url=https://www.lexico.com/definition/collapsar |archive-url=https://web.archive.org/web/20220323121829/https://www.lexico.com/definition/collapsar |url-status=dead |archive-date=March 23, 2022 |access-date=2022-03-23 |website=Lexico Dictionaries {{!}} English |language=en}} When a star no longer has enough fuel for significant fusion reactions, there are three possible outcomes, depending on the remnant star's mass: If it is less than the Chandrasekhar limit (1.4 solar masses), the star will stabilize and shrink, becoming a white dwarf; between the Chandrasekhar limit and the Tolman–Oppenheimer–Volkoff limit (approximately {{solar mass|2.9|link=y}}), it will become a neutron star; and above the Tolman–Oppenheimer–Volkoff limit, the star will become a black hole. However, it is theorized that the high density of neutron star cores allow for quark matter and, as a result, a star that is more massive than even the Tolman–Oppenheimer–Volkoff limit, yet still is not a black hole.{{cite journal |bibcode=2012ApJ...758L...7R |title=On the Induced Gravitational Collapse of a Neutron Star to a Black Hole by a Type Ib/C Supernova |last1=Rueda |first1=Jorge A. |last2=Ruffini |first2=Remo |journal=The Astrophysical Journal |year=2012 |volume=758 |issue=1 |pages=L7 |doi=10.1088/2041-8205/758/1/L7 |arxiv=1206.1684 |s2cid=119103016 }}

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