Editing Supernova (section)

==Milky Way candidates==
{{Main|List of supernova candidates}}
[[Image:Wolf rayet2.jpg|thumb|The [[Wolf–Rayet nebula|nebula]] around [[Wolf–Rayet star]] WR124, which is located at a distance of about 21,000 [[light-year]]s<ref>
{{cite journal
 |last1=Van Der Sluys |first1=M. V.
 |last2=Lamers |first2=H. J. G. L. M.
 |year=2003
 |title=The dynamics of the nebula M1-67 around the run-away Wolf-Rayet star WR 124
 |journal=Astronomy and Astrophysics
 |volume=398 |pages=181–194
 |arxiv=astro-ph/0211326
 |bibcode=2003A&A...398..181V
 |doi=10.1051/0004-6361:20021634
|s2cid=6142859
 }}</ref>]]

The next supernova in the Milky Way will likely be detectable even if it occurs on the far side of the galaxy. It is likely to be produced by the collapse of an unremarkable red supergiant, and it is very probable that it will already have been catalogued in infrared surveys such as [[2MASS]]. There is a smaller chance that the next core collapse supernova will be produced by a different type of massive star such as a yellow hypergiant, luminous blue variable, or Wolf–Rayet. The chances of the next supernova being a type Ia produced by a white dwarf are calculated to be about a third of those for a core collapse supernova. Again it should be observable wherever it occurs, but it is less likely that the progenitor will ever have been observed. It is not even known exactly what a type Ia progenitor system looks like, and it is difficult to detect them beyond a few parsecs. The total supernova rate in the Milky Way is estimated to be between 2 and 12 per century, although one has not actually been observed for several centuries.<ref name="adams">
{{cite journal
 |last1=Adams |first1=S. M.
 |last2=Kochanek |first2=C. S.
 |last3=Beacom |first3=J. F.
 |last4=Vagins |first4=M. R.
 |last5=Stanek |first5=K. Z.
 |year=2013
 |title=Observing the Next Galactic Supernova
 |journal=[[The Astrophysical Journal]]
 |volume=778 |issue=2 |pages=164
 |arxiv=1306.0559
 |bibcode=2013ApJ...778..164A
 |doi=10.1088/0004-637X/778/2/164
|s2cid=119292900
 }}</ref>

Statistically, the most common variety of core-collapse supernova is type II-P, and the progenitors of this type are red supergiants.<ref>{{Cite journal |last1=Cristofari |first1=P |last2=Marcowith |first2=A |last3=Renaud |first3=M |last4=Dwarkadas |first4=V V |last5=Tatischeff |first5=V |last6=Giacinti |first6=G |last7=Peretti |first7=E |last8=Sol |first8=H |date=2022-02-18 |title=The first days of Type II-P core collapse supernovae in the gamma-ray range |url=https://academic.oup.com/mnras/article/511/3/3321/6517473 |journal=Monthly Notices of the Royal Astronomical Society |language=en |volume=511 |issue=3 |pages=3321–3329 |doi=10.1093/mnras/stac217 |doi-access=free |issn=0035-8711|arxiv=2201.09583 }}</ref> It is difficult to identify which of those supergiants are in the final stages of heavy element fusion in their cores and which have millions of years left. The most-massive red supergiants shed their atmospheres and evolve to Wolf–Rayet stars before their cores collapse. All Wolf–Rayet stars end their lives from the Wolf–Rayet phase within a million years or so, but again it is difficult to identify those that are closest to core collapse. One class that is expected to have no more than a few thousand years before exploding are the WO Wolf–Rayet stars, which are known to have exhausted their core helium.<ref>
{{cite journal
 |last1=Tramper |first1=F.
 |last2=Straal |first2=S. M.
 |last3=Sanyal |first3=D.
 |last4=Sana |first4=H.
 |last5=De Koter |first5=A.
 |last6=Gräfener |first6=G.
 |last7=Langer |first7=N.
 |last8=Vink |first8=J. S.
 |last9=De Mink |first9=S. E.|author9-link=Selma de Mink
 |last10=Kaper |first10=L.
 |year=2015
 |title=Massive stars on the verge of exploding: The properties of oxygen sequence Wolf-Rayet stars
 |journal=Astronomy & Astrophysics
 |volume=581 |pages=A110
 |arxiv=1507.00839
 |bibcode=2015A&A...581A.110T
 |doi=10.1051/0004-6361/201425390
|s2cid=56093231
 }}</ref> Only eight of them are known, and only four of those are in the Milky Way.<ref name=tramper>
{{cite journal
 |last1=Tramper |first1=F.
 |last2=Gräfener |first2=G.
 |last3=Hartoog |first3=O. E.
 |last4=Sana |first4=H.
 |last5=De Koter |first5=A.
 |last6=Vink |first6=J. S.
 |last7=Ellerbroek |first7=L. E.
 |last8=Langer |first8=N.
 |last9=Garcia |first9=M.
 |last10=Kaper |first10=L.
 |last11=De Mink |first11=S. E.|author11-link=Selma de Mink
 |year=2013
 |title=On the nature of WO stars: A quantitative analysis of the WO3 star DR1 in IC 1613
 |journal=Astronomy & Astrophysics
 |volume=559 |pages=A72
 |arxiv=1310.2849
 |bibcode=2013A&A...559A..72T
 |doi=10.1051/0004-6361/201322155
|s2cid=216079684
 }}</ref>

A number of close or well-known stars have been identified as possible core collapse supernova candidates: the high-mass blue stars [[Spica]], [[Rigel]] and [[Deneb]],<ref>{{Cite journal |last=Firestone |first=R. B. |date=June 2014 |title=Observation of 23 Supernovae That Exploded |url=https://dx.doi.org/10.1088/0004-637X/789/1/29 |journal=The Astrophysical Journal |language=en |volume=789 |issue=1 |pages=29 |bibcode=2014ApJ...789...29F |doi=10.1088/0004-637X/789/1/29 |issn=0004-637X}}</ref> the red supergiants [[Betelgeuse]], [[Antares]], and [[VV Cephei|VV Cephei A]];<ref>
{{cite book
 |last1=Inglis |first1=M.
 |year=2015
 |chapter=Star Death: Supernovae, Neutron Stars & Black Holes
 |title=Astrophysics is Easy!
 |pages=203–223
 |series=The Patrick Moore Practical Astronomy Series
 |doi=10.1007/978-3-319-11644-0_12
 |isbn=978-3-319-11643-3
}}</ref><ref>{{Cite web |title=VV Cephei |url=http://stars.astro.illinois.edu/sow/vvcep.html |access-date=2024-04-14 |website=stars.astro.illinois.edu}}</ref><ref name=":2" /> the yellow hypergiant [[Rho Cassiopeiae]];<ref>
{{cite journal
 |last1=Lobel |first1=A.
 |last2=Stefanik |first2=R. P.
 |last3=Torres |first3=G.
 |last4=Davis |first4=R. J.
 |last5=Ilyin |first5=I.
 |last6=Rosenbush |first6=A. E.
 |year=2004
 |title=Spectroscopy of the Millennium Outburst and Recent Variability of the Yellow Hypergiant Rho Cassiopeiae
 |journal=Stars as Suns: Activity
 |volume=219 |pages=903
 |arxiv=astro-ph/0312074
 |bibcode=2004IAUS..219..903L
}}</ref> the luminous blue variable Eta Carinae that has already produced a supernova impostor;<ref>
{{cite journal
 |last1=Van Boekel |first1=R.
 |last2=Kervella |first2=P.
 |last3=Schöller |first3=M.
 |last4=Herbst |first4=T.
 |last5=Brandner |first5=W.
 |last6=De Koter |first6=A.
 |last7=Waters |first7=L. B. F. M.
 |last8=Hillier |first8=D. J.
 |last9=Paresce |first9=F.
 |last10=Lenzen |first10=R.
 |last11=Lagrange |first11=A.-M.
 |year=2003
 |title=Direct measurement of the size and shape of the present-day stellar wind of eta Carinae
 |journal=Astronomy and Astrophysics
 |volume=410 |issue=3 |pages=L37
 |arxiv=astro-ph/0310399
 |bibcode=2003A&A...410L..37V
 |doi=10.1051/0004-6361:20031500
|s2cid=18163131
 }}</ref> and both components, a blue supergiant and a Wolf–Rayet star, of the Regor or [[Gamma Velorum]] system.<ref>
{{cite book
 |last1=Thielemann |first1=F.-K.
 |last2=Hirschi |first2=R.
 |last3=Liebendörfer |first3=M.
 |last4=Diehl |first4=R.
 |year=2011
 |chapter=Massive Stars and Their Supernovae
 |title=Astronomy with Radioactivities
 |volume=812 |pages=153–231
 |series=Lecture Notes in Physics
 |doi=10.1007/978-3-642-12698-7_4
 |isbn=978-3-642-12697-0
|arxiv=1008.2144
 |bibcode=2011LNP...812..153T
 |s2cid=119254840
 }}</ref><ref>{{Cite web |title=Regor |url=http://stars.astro.illinois.edu/sow/regor.html |access-date=2024-08-18 |website=stars.astro.illinois.edu}}</ref> [[Mimosa (star)|Mimosa]], [[Acrux]] and Hadar or [[Beta Centauri]], three bright star systems in the southern constellation of [[Crux]] and [[Centaurus]] respectively, each contain blue stars with sufficient masses to explode as supernovae.<ref>{{Cite web |title=Acrux |url=http://stars.astro.illinois.edu/sow/acrux.html |access-date=2024-08-15 |website=stars.astro.illinois.edu}}</ref><ref>{{Cite web |title=Mimosa |url=http://stars.astro.illinois.edu/sow/mimosa.html |access-date=2024-08-15 |website=stars.astro.illinois.edu}}</ref><ref>{{Cite web| title=Hadar |url=http://stars.astro.illinois.edu/sow/hadar.html |access-date=2025-03-12 |website=stars.astro.illinois.edu}}</ref> Others have gained notoriety as possible, although not very likely, progenitors for a gamma-ray burst; for example [[WR 104]].<ref>
{{cite journal
 |last1=Tuthill |first1=P. G.
 |last2=Monnier |first2=J. D.
 |last3=Lawrance |first3=N.
 |last4=Danchi |first4=W. C.
 |last5=Owocki |first5=S. P.
 |last6=Gayley |first6=K. G.
 |year=2008
 |title=The Prototype Colliding-Wind Pinwheel WR 104
 |journal=The Astrophysical Journal
 |volume=675 |issue=1 |pages=698–710
 |arxiv=0712.2111
 |doi=10.1086/527286
 |bibcode=2008ApJ...675..698T
|s2cid=119293391
 }}</ref>

Identification of candidates for a type Ia supernova is much more speculative. Any binary with an accreting white dwarf might produce a supernova, although the exact mechanism and timescale is still debated. These systems are faint and difficult to identify, but the novae and [[recurrent nova]]e are such systems that conveniently advertise themselves. One example is [[U&nbsp;Scorpii]].<ref>
{{cite conference
 |last1=Thoroughgood |first1=T. D.
 | last2=Dhillon | first2=V. S.
 | last3=Littlefair | first3=S. P.
 | last4=Marsh | first4=T. R.
 | last5=Smith | first5=D. A.
 |date=2002
 |title=The recurrent nova U Scorpii – A type Ia supernova progenitor
 |book-title=The Physics of Cataclysmic Variables and Related Objects
 |volume=261
 |location=San Francisco, CA
 |publisher=[[Astronomical Society of the Pacific]]
 |arxiv=astro-ph/0109553
 |bibcode=2002ASPC..261...77T
}}</ref>

[[File:Supernova candidates.jpg|center|thumb|681x681px|Some of the closest core-collapse supernova candidates to Earth within one kiloparsec, most of which are K-type red supergiants<ref name=":2">{{Cite journal |last1=Mukhopadhyay |first1=Mainak |last2=Lunardini |first2=Cecilia |last3=Timmes |first3=F. X. |last4=Zuber |first4=Kai |date=2020-08-01 |title=Presupernova neutrinos: directional sensitivity and prospects for progenitor identification |journal=The Astrophysical Journal |volume=899 |issue=2 |pages=153 |doi=10.3847/1538-4357/ab99a6 |doi-access=free |arxiv=2004.02045 |bibcode=2020ApJ...899..153M |issn=0004-637X}}</ref>]]
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