Editing Star (section)

==Observation history==
{{seealso|Stars in astrology}}
[[File:Dibuix de Leo.png|thumb|A 1690 depiction of the constellation of [[Leo (constellation)|Leo]] the lion by [[Johannes Hevelius]].<ref>{{cite book
 | first=Johannis | last=Hevelius | date=1690
 | title=Firmamentum Sobiescianum, sive Uranographia
 | location=Gdansk}}</ref>]]

Historically, stars have been important to [[civilization]]s throughout the world. They have been part of religious practices, [[divination]] rituals, [[myth]]ology, used for [[celestial navigation]] and orientation, to mark the passage of seasons, and to define calendars.

Early astronomers recognized a difference between "[[fixed stars]]", whose position on the [[celestial sphere]] does not change, and "wandering stars" ([[planet]]s), which move noticeably relative to the fixed stars over days or weeks.<ref>{{cite web |date=n.d. |title=Ancient Greek Astronomy and Cosmology |url=https://www.loc.gov/collections/finding-our-place-in-the-cosmos-with-carl-sagan/articles-and-essays/modeling-the-cosmos/ancient-greek-astronomy-and-cosmology |access-date=28 February 2022 |website=Digital Collections |publisher=The [[Library of Congress]]}}</ref> Many ancient astronomers believed that the stars were permanently affixed to a [[heavenly sphere]] and that they were immutable. By convention, astronomers grouped prominent stars into [[asterism (astronomy)|asterisms]] and [[constellation]]s and used them to track the motions of the planets and the inferred position of the Sun.<ref name="forbes">{{cite book
 | last1=Forbes | first1=George | title=History of Astronomy
 | publisher=Watts & Co. | location=London | date=1909
 | url=http://www.gutenberg.org/ebooks/8172
 | isbn=((978-1-153-62774-0))}}</ref> The motion of the Sun against the background stars (and the horizon) was used to create [[solar calendar|calendars]], which could be used to regulate agricultural practices.<ref>{{cite web |last=Tøndering |first=Claus |date=2008 |title=Other Ancient Calendars |url=http://webexhibits.org/calendars/calendar-ancient.html |access-date=28 February 2022 |website=Calendars Through The Ages |publisher=Webexhibits}}</ref> The [[Gregorian calendar]], currently used nearly everywhere in the world, is a solar calendar based on the angle of the Earth's rotational axis relative to its local star, the Sun.

The oldest accurately dated [[star chart]] was the result of ancient [[Egyptian astronomy]] in 1534&nbsp;BC.<ref>{{cite journal
 | last=von Spaeth | first=Ove
 | title=Dating the Oldest Egyptian Star Map
 | journal=[[Centaurus (journal)|Centaurus]]
 | date=2000 | volume=42 | issue=3 | pages=159–179
 | url=http://www.moses-egypt.net/star-map/senmut1-mapdate_en.asp
 | access-date=2007-10-21 | doi=10.1034/j.1600-0498.2000.420301.x|bibcode= 2000Cent...42..159V}}</ref> The [[Babylonian star catalogues|earliest known star catalogues]] were compiled by the ancient [[Babylonian astronomy|Babylonian astronomers]] of [[Mesopotamia]] in the late 2nd millennium BC, during the [[Kassites|Kassite Period]] ({{Circa|1531 BC|1155 BC}}).<ref name="north 1995 30 31">{{cite book
 | last=North | first=John | date=1995
 | title=The Norton History of Astronomy and Cosmology
 | url=https://archive.org/details/nortonhistoryofa0000nort | url-access=registration | location=New York and London | pages=[https://archive.org/details/nortonhistoryofa0000nort/page/30 30–31]
 | publisher=W.W. Norton & Company | isbn=978-0-393-03656-5}}</ref>
[[File:Свет от деревни - panoramio.jpg|alt=Alternative text|thumb|Stars in the night sky]]
The first [[star catalogue]] in [[Ancient Greek astronomy|Greek astronomy]] was created by [[Aristillus]] in approximately 300&nbsp;BC, with the help of [[Timocharis]].<ref>{{cite book
 | last=Murdin | first=P. |date=2000
 | chapter=Aristillus (c. 200 BC)
 | doi=10.1888/0333750888/3440
 | title=Encyclopedia of Astronomy and Astrophysics
 | bibcode=2000eaa..bookE3440.
 | isbn=978-0-333-75088-9}}</ref> The star catalog of [[Hipparchus]] (2nd century BC) included 1,020 stars, and was used to assemble [[Ptolemy]]'s star catalogue.<ref>{{cite book
 | first=Gerd | last=Grasshoff | date=1990
 | title=The history of Ptolemy's star catalogue
 | publisher=Springer | pages=1–5 | isbn=978-0-387-97181-0}}</ref> Hipparchus is known for the discovery of the first recorded ''[[nova]]'' (new star).<ref>{{cite web |last=Pinotsis |first=Antonios D. |date=2008 |title=Astronomy in Ancient Rhodes |url=http://conferences.phys.uoa.gr/jets2008/historical.html |url-status=dead |archive-url=https://web.archive.org/web/20210907070144/http://conferences.phys.uoa.gr/jets2008/historical.html |archive-date=September 7, 2021 |access-date=February 28, 2022 |website=Protostellar Jets In Context |publisher=[[University of Athens]], Greece}}</ref> Many of the constellations and star names in use today derive from Greek astronomy.

Despite the apparent immutability of the heavens, [[Chinese astronomy|Chinese astronomers]] were aware that new stars could appear.<ref name="clark">{{cite conference |last1=Clark |first1=D. H. |last2=Stephenson |first2=F. R. |date=1981-06-29 |title=The Historical Supernovae |conference=Advanced Study Institute |location=Cambridge, UK |publisher=Dordrecht, D. Reidel Publishing Company |pages=355–370 |bibcode=1982ASIC...90..355C |book-title=Supernovae: A survey of current research; Proceedings of the Advanced Study Institute}}</ref> In 185&nbsp;AD, they were the first to observe and write about a [[supernova]], now known as [[SN 185]].<ref>{{cite journal |last1=Zhao |first1=Fu-Yuan |last2=Strom |first2=R. G. |last3=Jiang |first3=Shi-Yang |date=2006 |title=The Guest Star of AD185 must have been a Supernova |journal=Chinese Journal of Astronomy and Astrophysics |volume=6 |issue=5 |pages=635 |bibcode=2006ChJAA...6..635Z |doi=10.1088/1009-9271/6/5/17 |doi-access=free }}</ref> The brightest stellar event in recorded history was the [[SN 1006]] supernova, which was observed in 1006 and written about by the Egyptian astronomer [[Ali ibn Ridwan]] and several Chinese astronomers.<ref>{{cite web |last1=Isbell |first1=Douglas |last2=Benoit |first2=Phil |date=5 March 2003 |title=Astronomers Peg Brightness of History's Brightest Star |url=http://www.noao.edu/outreach/press/pr03/pr0304.html |url-status=dead |archive-url=https://web.archive.org/web/20030402121341/http://www.noao.edu/outreach/press/pr03/pr0304.html |archive-date=2 April 2003 |access-date=28 February 2022 |website=NOIRLab |publisher=National Optical Astronomy Observatory}}</ref> The [[SN 1054]] supernova, which gave birth to the [[Crab Nebula]], was also observed by Chinese and Islamic astronomers.<ref name="SN1054">{{cite web
 | last1=Frommert | first1=Hartmut | last2=Kronberg | first2=Christine
 | date=2006-08-30 | work=SEDS
 | publisher=University of Arizona
 | title=Supernova 1054 – Creation of the Crab Nebula
 | url=http://messier.seds.org/more/m001_sn.html
}}</ref><ref name="PASP1942">{{cite journal
 | last=Duyvendak | first=J. J. L.
 | title=Further Data Bearing on the Identification of the Crab Nebula with the Supernova of 1054 A.D. Part I. The Ancient Oriental Chronicles
 | journal=Publications of the Astronomical Society of the Pacific | volume=54 | issue=318 | pages=91–94
 |date=April 1942 | bibcode=1942PASP...54...91D
 | doi=10.1086/125409| doi-access=free}}<br />
{{Cite journal
 | last1=Mayall | first1=N. U. | last2=Oort |first2=Jan Hendrik
 | title=Further Data Bearing on the Identification of the Crab Nebula with the Supernova of 1054 A.D. Part II. The Astronomical Aspects
 | journal=Publications of the Astronomical Society of the Pacific | volume=54 | issue=318 | pages=95–104 |date=April 1942 | bibcode=1942PASP...54...95M
 | doi=10.1086/125410
| doi-access=free }}</ref><ref>{{cite journal | display-authors=1
 | last1=Brecher | first1=K. | last2=Fesen | first2=R. A.
 | last3=Maran | first3=S. P. | last4=Brandt | first4=J. C. | date=1983
 | title=Ancient records and the Crab Nebula supernova
 | journal=The Observatory | volume=103 | pages=106–113
 | bibcode=1983Obs...103..106B}}</ref>

[[Astronomy in the medieval Islamic world|Medieval Islamic astronomers]] gave [[list of Arabic star names|Arabic names to many stars]] that are still used today and they invented numerous [[astronomy in medieval Islam#Instruments|astronomical instruments]] that could compute the positions of the stars. They built the first large [[observatory]] research institutes, mainly to produce ''[[Zij]]'' star catalogues.<ref>{{cite journal
 |last=Kennedy |first=Edward S. |date=1962
 |title=Review: ''The Observatory in Islam and Its Place in the General History of the Observatory'' by Aydin Sayili
 |journal=[[Isis (journal)|Isis]] |volume=53
 |issue=2 |pages=237–239 |doi=10.1086/349558}}</ref> Among these, the ''[[Book of Fixed Stars]]'' (964) was written by the [[Persian people|Persian]] astronomer [[Abd al-Rahman al-Sufi]], who observed a number of stars, [[star cluster]]s (including the [[Omicron Velorum]] and [[Brocchi's Cluster]]s) and [[galaxy|galaxies]] (including the [[Andromeda Galaxy]]).<ref name=Jones>{{cite book
 | title=Messier's nebulae and star clusters
 | url=https://books.google.com/books?id=IuhLR35I9QUC
 | first=Kenneth Glyn | last=Jones
 | publisher=[[Cambridge University Press]]
 | date=1991 | isbn=978-0-521-37079-0 | page=1}}</ref> According to A. Zahoor, in the 11th century, the Persian [[polymath]] scholar [[Abu Rayhan Biruni]] described the [[Milky Way]] galaxy as a multitude of fragments having the properties of [[nebula|nebulous]] stars, and gave the [[latitude]]s of various stars during a [[lunar eclipse]] in 1019.<ref>{{cite web
 | last=Zahoor | first=A. | date=1997
 | url=http://www.unhas.ac.id/~rhiza/saintis/biruni.html
 | archive-url=https://web.archive.org/web/20080626074150/http://www.unhas.ac.id/~rhiza/saintis/biruni.html
 | archive-date=2008-06-26
 | title=Al-Biruni | publisher=Hasanuddin University
 | access-date=2007-10-21}}</ref>

According to Josep Puig, the [[Al-Andalus|Andalusian]] astronomer [[Ibn Bajjah]] proposed that the Milky Way was made up of many stars that almost touched one another and appeared to be a continuous image due to the effect of [[refraction]] from sublunary material, citing his observation of the [[conjunction (astronomy and astrology)|conjunction]] of Jupiter and Mars on 500 [[Islamic calendar|AH]] (1106/1107&nbsp;AD) as evidence.<ref name=Montada>{{cite encyclopedia
 | first=Josep Puig | last=Montada
 | title=Ibn Bajja | encyclopedia=[[Stanford Encyclopedia of Philosophy]]
 | url= http://plato.stanford.edu/entries/ibn-bajja
 | date=2007-09-28 | access-date=2008-07-11}}</ref> <!--
[[File:Andromedaurania.jpg|thumb|[[Andromeda (constellation)|Andromeda]] as depicted in ''Urania's Mirror'', set of [[constellation]] cards published in London c. 1825]] -->
Early European astronomers such as [[Tycho Brahe]] identified new stars in the [[night sky]] (later termed ''novae''), suggesting that the heavens were not immutable. In 1584, [[Giordano Bruno]] suggested that the stars were like the Sun, and may have [[extrasolar planet|other planets]], possibly even Earth-like, in orbit around them,<ref name="he history">{{cite web
 | last=Drake | first=Stephen A. | date=2006-08-17
 | url=http://heasarc.gsfc.nasa.gov/docs/heasarc/headates/heahistory.html
 | title=A Brief History of High-Energy (X-ray & Gamma-Ray) Astronomy
 | publisher=NASA HEASARC | access-date=2006-08-24
}}</ref> an idea that had been suggested earlier by the ancient [[Greek philosophy|Greek philosophers]], [[Democritus]] and [[Epicurus]],<ref>{{cite web | first1=Peter | last1=Greskovic | first2=Peter | last2=Rudy | date=2006-07-24 | url=http://www.eso.org/public/outreach/eduoff/cas/cas2004/casreports-2004/rep-228/ | title=Exoplanets | publisher=ESO | access-date=2012-06-15 | archive-date=10 October 2008 | archive-url=https://web.archive.org/web/20081010140635/http://www.eso.org/public/outreach/eduoff/cas/cas2004/casreports-2004/rep-228/ | url-status=dead }}</ref> and by medieval [[Cosmology in medieval Islam|Islamic cosmologists]]<ref>{{cite journal
 | title=The impact of the Qur'anic conception of astronomical phenomena on Islamic civilization
 | first=I. A. | last=Ahmad | journal=Vistas in Astronomy
 | volume=39 | issue=4 | date=1995
 | pages=395–403 [402]
 | doi=10.1016/0083-6656(95)00033-X |bibcode= 1995VA.....39..395A}}</ref> such as [[Fakhr al-Din al-Razi]].<ref name="Setia">{{cite journal|title= Fakhr Al-Din Al-Razi on Physics and the Nature of the Physical World: A Preliminary Survey|first= Adi|last= Setia|journal= Islam & Science|volume= 2|date= 2004|issue= 2|url= http://www.cis-ca.org/jol/vol2-no2/adi.pdf|access-date= 26 May 2018|archive-date= 9 January 2020|archive-url= https://web.archive.org/web/20200109010911/http://www.cis-ca.org/jol/vol2-no2/adi.pdf|url-status= dead}}</ref> By the following century, the idea of the stars being the same as the Sun was reaching a consensus among astronomers. To explain why these stars exerted no net gravitational pull on the Solar System, [[Isaac Newton]] suggested that the stars were equally distributed in every direction, an idea prompted by the theologian [[Richard Bentley]].<ref>{{cite journal
 | last=Hoskin | first=Michael | date=1998
 | url=http://www.stsci.edu/stsci/meetings/lisa3/hoskinm.html
 | title=The Value of Archives in Writing the History of Astronomy
 | journal=Library and Information Services in Astronomy III | volume=153 | pages=207 | access-date=2006-08-24| bibcode=1998ASPC..153..207H }}</ref>

The Italian astronomer [[Geminiano Montanari]] recorded observing variations in luminosity of the star [[Algol]] in 1667. [[Edmond Halley]] published the first measurements of the [[proper motion]] of a pair of nearby "fixed" stars, demonstrating that they had changed positions since the time of the ancient [[Ancient Greece|Greek]] astronomers Ptolemy and Hipparchus.<ref name="he history" />

[[William Herschel]] was the first astronomer to attempt to determine the distribution of stars in the sky. During the 1780s, he established a series of gauges in 600 directions and counted the stars observed along each line of sight. From this, he deduced that the number of stars steadily increased toward one side of the sky, in the direction of the Milky Way [[Galactic Center|core]]. His son [[John Herschel]] repeated this study in the southern hemisphere and found a corresponding increase in the same direction.<ref>{{cite journal
 | last=Proctor | first=Richard A.
 | title=Are any of the nebulæ star-systems? | journal=Nature
 | date=1870 | pages=331–333
 | url=http://digicoll.library.wisc.edu/cgi-bin/HistSciTech/HistSciTech-idx?type=div&did=HISTSCITECH.0012.0052.0005&isize=M
 | issue=13
 | doi=10.1038/001331a0 | volume=1 |bibcode= 1870Natur...1..331P| doi-access=free}}</ref> In addition to his other accomplishments, William Herschel is noted for his discovery that some stars do not merely lie along the same line of sight, but are physical companions that form binary star systems.<ref name="Magill1992">{{cite book |author=Magill |first=Frank Northen |url=https://books.google.com/books?id=W33WAAAAMAAJ |title=Magill's Survey of Science: A-Cherenkov detectors |publisher=Salem Press |year=1992 |isbn=978-0-89356-619-7 |page=219}}</ref>

The science of [[astronomical spectroscopy|stellar spectroscopy]] was pioneered by [[Joseph von Fraunhofer]] and [[Angelo Secchi]]. By comparing the spectra of stars such as [[Sirius]] to the Sun, they found differences in the strength and number of their [[spectral line|absorption lines]]—the dark lines in stellar spectra caused by the atmosphere's absorption of specific frequencies. In 1865, Secchi began classifying stars into [[stellar classification|spectral types]].<ref>{{cite web
 | last=MacDonnell | first=Joseph
 | url=http://www.faculty.fairfield.edu/jmac/sj/scientists/secchi.htm
 | archive-url=https://web.archive.org/web/20110721210124/http://www.faculty.fairfield.edu/jmac/sj/scientists/secchi.htm
 | archive-date=2011-07-21
 | title=Angelo Secchi, S.J. (1818–1878) the Father of Astrophysics
 | publisher=[[Fairfield University]]
 | access-date=2006-10-02}}</ref> The modern version of the stellar classification scheme was developed by [[Annie Jump Cannon|Annie J. Cannon]] during the early 1900s.<ref name="HubenyMihalas2014">{{cite book |last1=Hubeny |first1=Ivan |url=https://books.google.com/books?id=TmuYDwAAQBAJ&pg=PA23 |title=Theory of Stellar Atmospheres: An Introduction to Astrophysical Non-equilibrium Quantitative Spectroscopic Analysis |last2=Mihalas |first2=Dimitri |date=2014 |publisher=Princeton University Press |isbn=978-0-691-16329-1 |page=23}}</ref>

The first direct measurement of the distance to a star ([[61 Cygni]] at 11.4 [[light-years]]) was made in 1838 by [[Friedrich Bessel]] using the [[parallax]] technique. Parallax measurements demonstrated the vast separation of the stars in the heavens.<ref name="he history" /> Observation of double stars gained increasing importance during the 19th century. In 1834, Friedrich Bessel observed changes in the proper motion of the star Sirius and inferred a hidden companion. [[Edward Charles Pickering|Edward Pickering]] discovered the first [[spectroscopic binary]] in 1899 when he observed the periodic splitting of the spectral lines of the star [[Mizar (star)|Mizar]] in a 104-day period. Detailed observations of many binary star systems were collected by astronomers such as [[Friedrich Georg Wilhelm von Struve]] and [[Sherburne Wesley Burnham|S. W. Burnham]], allowing the masses of stars to be determined from computation of [[orbital elements]]. The first solution to the problem of deriving an orbit of binary stars from telescope observations was made by Felix Savary in 1827.<ref>{{cite book
 | first=Robert G. | last=Aitken | title=The Binary Stars | page=66
 | publisher=Dover Publications Inc. | location=New York
 | date=1964 | isbn=((978-0-486-61102-0))}}</ref>

The twentieth century saw increasingly rapid advances in the scientific study of stars. The photograph became a valuable astronomical tool. [[Karl Schwarzschild]] discovered that the color of a star and, hence, its temperature, could be determined by comparing the [[visual magnitude]] against the [[photographic magnitude]]. The development of the [[Photoelectric effect|photoelectric]] [[photometer]] allowed precise measurements of magnitude at multiple wavelength intervals. In 1921 [[Albert A. Michelson]] made the first measurements of a stellar diameter using an [[interferometer]] on the [[100-inch Hooker telescope|Hooker telescope]] at [[Mount Wilson Observatory]].<ref>{{cite journal
 | last1=Michelson | first1=A. A. | last2=Pease | first2=F. G.
 | title=Measurement of the diameter of Alpha Orionis with the interferometer
 | journal=Astrophysical Journal | date=1921 | volume=53 | issue=5 | pages=249–259
 | bibcode=1921ApJ....53..249M | doi= 10.1086/142603 | pmid=16586823 | pmc=1084808 | s2cid=21969744 }}</ref>

Important theoretical work on the physical structure of stars occurred during the first decades of the twentieth century. In 1913, the [[Hertzsprung-Russell diagram]] was developed, propelling the astrophysical study of stars. Successful [[Stellar model|models]] were developed to explain the interiors of stars and stellar evolution. [[Cecilia Payne-Gaposchkin]] first proposed that stars were made primarily of hydrogen and helium in her 1925 PhD thesis.<ref>{{cite web
 |url        = http://cwp.library.ucla.edu/Phase2/Payne-Gaposchkin,_Cecilia_Helena@861234567.html
 |archive-url = https://web.archive.org/web/20050318221903/http://cwp.library.ucla.edu/Phase2/Payne-Gaposchkin,_Cecilia_Helena@861234567.html
 |url-status=dead
 |archive-date = 2005-03-18
 |title      = " Payne-Gaposchkin, Cecilia Helena." CWP
 |publisher  = [[University of California]]
 |access-date = 2013-02-21
}}</ref> The spectra of stars were further understood through advances in [[quantum mechanics|quantum physics]]. This allowed the chemical composition of the stellar atmosphere to be determined.<ref name="new cosmos">{{cite book
 | last1=Unsöld | first1=Albrecht | title=The New Cosmos
 | publisher=Springer | location=New York
 | date=2001 | edition=5th | pages=180–185, 215–216
 | isbn=978-3-540-67877-9}}</ref>

[[File:Milky Way IR Spitzer.jpg|thumb|[[Spitzer Space Telescope]] infrared image showing a multitude of stars in the [[Milky Way]] galaxy]]
With the exception of rare events such as supernovae and [[supernova impostor]]s, individual stars have primarily been observed in the [[Local Group]],<ref name=gordon2016>{{Cite journal|last1=Gordon|first1=Michael S.|last2=Humphreys|first2=Roberta M.|last3=Jones|first3=Terry J.|date=July 2016|title=Luminous and Variable Stars in M31 and M33. III. The Yellow and Red Supergiants and Post-red Supergiant Evolution|journal=The Astrophysical Journal|language=en|volume=825|issue=1|pages=50|doi=10.3847/0004-637X/825/1/50|arxiv=1603.08003|bibcode=2016ApJ...825...50G|s2cid=119281102|issn=0004-637X |doi-access=free }}</ref> and especially in the visible part of the Milky Way (as demonstrated by the detailed star catalogues available for the Milky Way galaxy) and its satellites.<ref>{{cite Gaia EDR3}}</ref> Individual stars such as Cepheid variables have been observed in the [[Messier 87|M87]]<ref>{{cite journal |bibcode=2020ApJS..246....3D |title=Clustering of Local Group Distances: Publication Bias or Correlated Measurements? VI. Extending to Virgo Cluster Distances |last1=De Grijs |first1=Richard |last2=Bono |first2=Giuseppe |journal=The Astrophysical Journal Supplement Series |year=2020 |volume=246 |issue=1 |page=3 |doi=10.3847/1538-4365/ab5711 |arxiv=1911.04312 |s2cid=207852888 |doi-access=free }}
</ref> and [[Messier 100|M100]] galaxies of the [[Virgo Cluster]],<ref>{{cite web
 | last1=Villard | first1=Ray | last2=Freedman | first2=Wendy L.
 | date=1994-10-26
 | url=http://hubblesite.org/newscenter/archive/releases/1994/1994/49/text/
 | title=Hubble Space Telescope Measures Precise Distance to the Most Remote Galaxy Yet
 | publisher=Hubble Site
 | access-date= 2007-08-05}}</ref> as well as luminous stars in some other relatively nearby galaxies.<ref>{{cite journal |bibcode=2020MNRAS.497.4834S |title=New luminous blue variable candidates in the NGC 247 galaxy |last1=Solovyeva |first1=Y. |last2=Vinokurov |first2=A. |last3=Sarkisyan |first3=A. |last4=Atapin |first4=K. |last5=Fabrika |first5=S. |last6=Valeev |first6=A. F. |last7=Kniazev |first7=A. |last8=Sholukhova |first8=O. |last9=Maslennikova |first9=O. |journal=Monthly Notices of the Royal Astronomical Society |year=2020 |volume=497 |issue=4 |page=4834 |doi=10.1093/mnras/staa2117 |doi-access=free |arxiv=2008.06215 |s2cid=221451751 }}
</ref> With the aid of [[gravitational lensing]], a single star (named [[Icarus (star)|Icarus]]) has been observed at 9&nbsp;billion light-years away.<ref name="NA-20180402">{{cite journal |author=Kelly, Patrick L. |display-authors=etal |title=Extreme magnification of an individual star at redshift 1.5 by a galaxy-cluster lens |date=2018-04-02 |journal=[[Nature (journal)|Nature]] |volume=2 |issue=4 |pages=334–342 |doi=10.1038/s41550-018-0430-3 |arxiv=1706.10279 |bibcode=2018NatAs...2..334K |s2cid=125826925 }}</ref><ref name="SPC-20180402">{{cite web |last=Howell |first=Elizabeth |title=Rare Cosmic Alignment Reveals Most Distant Star Ever Seen |url=https://www.space.com/40171-cosmic-alignment-reveals-most-distant-star-yet.html |date=2018-04-02|work=[[Space.com]] |access-date=2018-04-02 }}</ref>