Editing SN 1987A (section)

== Progenitor ==
{{Main|Sanduleak −69 202}}
Four days after the event was recorded, the progenitor star was tentatively identified as {{nowrap|Sanduleak −69 202}} ({{nowrap|Sk −69 202}}), a [[blue supergiant]].<ref>
{{Cite book
 |last=Sonneborn |first=G.
 |year=1987
 |chapter=The Progenitor of SN1987A
 |editor-last1=Kafatos |editor-first1=M.
 |editor-last2=Michalitsianos |editor-first2=A.
 |editor2-link=Andreas Gerasimos Michalitsianos
 |title=Supernova 1987a in the Large Magellanic Cloud
 |publisher=[[Cambridge University Press]]
 |isbn=978-0-521-35575-9
}}</ref>
After the supernova faded, that identification was definitively confirmed, as {{nowrap|Sk −69 202}} had disappeared. The possibility of a blue supergiant producing a supernova was considered surprising,{{sfn|Walborn|1988|p=3}} and the confirmation led to further research which identified an earlier supernova with a blue supergiant progenitor.{{sfn|Gaskell|Keel|1988|p=13}}

Some models of SN 1987A's progenitor attributed the blue color largely to its chemical composition rather than its evolutionary stage, particularly the low levels of heavy elements.<ref name=Arnett>
{{cite journal
 |last1=Arnett |first1=W. D.
 |last2=Bahcall |first2=J. N.
 |last3=Kirshner |first3=R. P.
 |last4=Woosley |first4=S. E.
 |year=1989
 |title=Supernova 1987A
 |journal=[[Annual Review of Astronomy and Astrophysics]]
 |volume=27 |pages=629–700
 |bibcode=1989ARA&A..27..629A
 |doi=10.1146/annurev.aa.27.090189.003213
}}</ref> There was some speculation that the star might have merged with a [[Binary star|companion star]] before the supernova.<ref>
{{Cite journal
 |last1=Podsiadlowski |first1=P.
 |year=1992
 |title=The progenitor of SN 1987 A
 |journal=[[Publications of the Astronomical Society of the Pacific]]
 |volume=104 |issue=679 |page=717
 |bibcode=1992PASP..104..717P
 |doi=10.1086/133043
 |doi-access=free
}}</ref> However, it is now widely understood that blue supergiants are natural progenitors of some supernovae, although there is still speculation that the evolution of such stars could require mass loss involving a binary companion.<ref name=dwarkadas>
{{Cite journal
 |last1=Dwarkadas |first1=V. V.
 |year=2011
 |title=On luminous blue variables as the progenitors of core-collapse supernovae, especially Type IIn supernovae
 |journal=[[Monthly Notices of the Royal Astronomical Society]]
 |volume=412 |issue=3 |pages=1639–1649
 |arxiv=1011.3484
 |bibcode=2011MNRAS.412.1639D
 |doi=10.1111/j.1365-2966.2010.18001.x
 |doi-access=free
 |s2cid=118359033
}}</ref>