Editing SN 1987A (section)

==Neutron star==
SN 1987A appears to be a core-collapse supernova, which should result in a [[neutron star]] given the size of the original star.<ref name=Arnett/> The neutrino data indicate that a compact object did form at the star's core, and astronomers immediately began searching for the collapsed core. The [[Hubble Space Telescope]] took images of the supernova regularly from August 1990 without a clear detection of a neutron star.

A number of possibilities for the "missing" neutron star were considered.<ref name=alp18b>
{{cite journal
 |last1=Alp |first1=D.
 |display-authors=etal
 |year=2018
 |title=The 30 Year Search for the Compact Object in SN 1987A
 |journal=[[The Astrophysical Journal]]
 |volume=864 |issue=2 |pages=174
 |arxiv=1805.04526
 |bibcode=2018ApJ...864..174A
 |doi=10.3847/1538-4357/aad739
 |s2cid=51918880
|doi-access=free
 }}</ref> First, that the neutron star may be obscured by surrounding dense dust clouds.<ref name="Template SN1987A">
{{Cite journal
 |last1=Orlando |first1=S.
 |display-authors=etal
 |year=2015
 |title=Supernova 1987A: A Template to Link Supernovae to Their Remnants
 |journal=[[The Astrophysical Journal]]
 |volume=810 |issue=2|pages=168
 |arxiv=1508.02275
 |bibcode=2015ApJ...810..168O
 |doi=10.1088/0004-637X/810/2/168
 |s2cid=118545009
}}</ref> Second, that a [[pulsar]] was formed, but with either an unusually large or small magnetic field. Third, that large amounts of material fell back on the neutron star, collapsing it further into a [[black hole]]. Neutron stars and [[Black hole|black holes]] often give off light as material falls onto them. If there is a compact object in the supernova remnant, but no material to fall onto it, it would be too dim for detection. A fourth hypothesis is that the collapsed core became a [[quark star]].<ref>
{{Cite journal
 |last1=Chan |first1=T. C.
 |display-authors=etal
 |date=2009
 |title=Could the compact remnant of SN 1987A be a quark star?
 |journal=[[The Astrophysical Journal]]
 |volume=695 |issue=1|pages=732–746
 |arxiv=0902.0653
 |bibcode=2009ApJ...695..732C
 |doi=10.1088/0004-637X/695/1/732
 |s2cid=14402008
}}</ref><ref>
{{Cite news
 |last=Parsons |first=P.
 |date=February 21, 2009
 |title=Quark star may hold secret to early universe
 |newspaper=[[New Scientist]]
 |url=https://www.newscientist.com/article/mg20126964.700-quark-star-may-hold-secret-to-early-universe.html
 |archive-url=https://web.archive.org/web/20150318100318/http://www.newscientist.com/article/mg20126964.700-quark-star-may-hold-secret-to-early-universe.html
 |archive-date=March 18, 2015
 |url-status=live
}}</ref>

In 2019, evidence was presented for a neutron star inside one of the brightest dust clumps, close to the expected position of the supernova remnant.<ref>
{{cite journal
 |last1=Cigan |first1=Phil
 |last2=Matsuura |first2=Mikako
 |last3=Gomez |first3=Haley L.
 |last4=Indebetouw |first4=Remy
 |last5=Abellán |first5=Fran
 |last6=Gabler |first6=Michael
 |last7=Richards |first7=Anita
 |last8=Alp |first8=Dennis
 |last9=Davis |first9=Timothy A.
 |last10=Janka |first10=Hans-Thomas
 |last11=Spyromilio |first11=Jason
 |last12=Barlow |first12=M. J.
 |last13=Burrows |first13=David
 |last14=Dwek |first14=Eli
 |last15=Fransson |first15=Claes
 |last16=Gaensler |first16=Bryan
 |last17=Larsson |first17=Josefin
 |last18=Bouchet |first18=P.
 |last19=Lundqvist |first19=Peter
 |last20=Marcaide |first20=J. M.
 |last21=Ng |first21=C.-Y.
 |last22=Park |first22=Sangwook
 |last23=Roche |first23=Pat
 |last24=Van Loon |first24=Jacco Th.
 |last25=Wheeler |first25=J. C.
 |last26=Zanardo |first26=Giovanna
 |display-authors=1
 |year=2019
 |title=High Angular Resolution ALMA Images of Dust and Molecules in the SN 1987A Ejecta
 |journal=[[The Astrophysical Journal]]
 |volume=886 |issue=1 |pages=51
 |arxiv=1910.02960
 |bibcode=2019ApJ...886...51C
 |doi=10.3847/1538-4357/ab4b46
 |s2cid=203902478
|doi-access=free
 }}</ref><ref>
{{Cite web
 |last=Gough |first=Evan
 |date=2019-11-21
 |url=https://www.universetoday.com/144107/astronomers-finally-find-the-neutron-star-leftover-from-supernova-1987a/
 |title=Astronomers Finally Find the Neutron Star Leftover from Supernova 1987A
 |website=[[Universe Today]]
 |language=en-US
 |access-date=2019-12-06
}}</ref> In 2021, further evidence was presented of hard X-ray emissions from SN 1987A originating in the pulsar wind nebula.<ref>
{{cite journal
 |last1=Greco |first1=Emanuele
 |last2=Miceli |first2=Marco
 |last3=Orlando |first3=Salvatore
 |last4=Olmi |first4=Barbara
 |last5=Bocchino |first5=Fabrizio
 |last6=Nagataki |first6=Shigehiro
 |last7=Ono |first7=Masaomi
 |last8=Dohi |first8=Akira
 |last9=Peres |first9=Giovanni
 |year=2021
 |title=Indication of a Pulsar Wind Nebula in the Hard X-Ray Emission from SN 1987A
 |journal=The Astrophysical Journal
 |volume=908 |issue=2 |pages=L45
 |arxiv=2101.09029
 |bibcode=2021ApJ...908L..45G
 |doi=10.3847/2041-8213/abdf5a
 |s2cid=231693022
|doi-access=free
 }}</ref><ref>
{{Cite web
 |last=Johnston |first=Scott Alan
 |date=2021-02-26
 |title=Astronomers Think They've Found the Neutron Star Remnant Left Behind from Supernova 1987A
 |url=https://www.universetoday.com/150289/astronomers-think-theyve-found-the-neutron-star-remnant-left-behind-from-supernova-1987a/
 |website=[[Universe Today]]
 |language=en-US
 |access-date=2021-02-26
}}</ref> The latter result is supported by a three-dimensional [[magnetohydrodynamic]] model, which describes the evolution of SN 1987A from the SN event to the present, and reconstructs the ambient environment, predicting the absorbing power of the dense stellar material around the pulsar.<ref>
{{cite journal
 |last1=Orlando |first1=Salvatore
 |last2=Ono |first2=Masaomi
 |last3=Nagataki |first3=Shigehiro
 |last4=Miceli |first4=Marco
 |last5=Umeda |first5=Hideyuk
 |last6=Ferrand |first6=Gilles
 |last7=Bocchino |first7=Fabrizio
 |last8=Petruk |first8=Oleh
 |last9=Peres |first9=Giovanni
 |last10=Takahashi |first10=Koh
 |last11=Yoshida |first11=Takashi
 |display-authors=1
 |year=2020
 |title=Hydrodynamic simulations unravel the progenitor-supernova-remnant connection in SN 1987A
 |journal=[[Astronomy & Astrophysics]]
 |volume=636 |pages=A22
 |arxiv=1912.03070
 |bibcode=2020A&A...636A..22O
 |doi=10.1051/0004-6361/201936718
 |s2cid=208857686
}}</ref>

In 2024, researchers using the [[James Webb Space Telescope]] (JWST) identified distinctive emission lines of ionized [[argon]] within the central region of the Supernova 1987A remnants. These emission lines, discernible only near the remnant's core, were analyzed using [[photoionization]] models. The models indicate that the observed line ratios and velocities can be attributed to ionizing radiation originating from a neutron star illuminating gas from the inner regions of the exploded star.<ref name=":0">{{Cite journal |last1=Fransson |first1=C. |last2=Barlow |first2=M. J. |last3=Kavanagh |first3=P. J. |last4=Larsson |first4=J. |last5=Jones |first5=O. C. |last6=Sargent |first6=B. |last7=Meixner |first7=M. |last8=Bouchet |first8=P. |last9=Temim |first9=T. |last10=Wright |first10=G. S. |last11=Blommaert |first11=J. A. D. L. |last12=Habel |first12=N. |last13=Hirschauer |first13=A. S. |last14=Hjorth |first14=J. |last15=Lenkić |first15=L. |date=2024-02-23 |title=Emission lines due to ionizing radiation from a compact object in the remnant of Supernova 1987A |url=https://www.science.org/doi/10.1126/science.adj5796 |journal=Science |language=en |volume=383 |issue=6685 |pages=898–903 |doi=10.1126/science.adj5796 |pmid=38386759 |issn=0036-8075|arxiv=2403.04386 |bibcode=2024Sci...383..898F }}</ref>