Editing Ophiuchus (section)

===Stars===
{{See also|List of stars in Ophiuchus}}

The brightest stars in Ophiuchus include [[Alpha Ophiuchi|α Ophiuchi]], called Rasalhague ("head of the serpent charmer"), at magnitude&nbsp;2.07, and [[Eta Ophiuchi|η Ophiuchi]], known as Sabik ("the preceding one"), at magnitude&nbsp;2.43.<ref>Chartrand III, Mark R.; (1983) ''Skyguide: A Field Guide for Amateur Astronomers'', p. 170 ({{ISBN|0-307-13667-1}}).</ref><ref name="Hoffleit 1991">{{cite web | url=http://vizier.u-strasbg.fr/viz-bin/VizieR-S?HR%202491 | title=Entry for HR 2491 | work=Bright Star Catalogue, 5th Revised Ed. (Preliminary Version) |author1=Hoffleit, D. |author2=Warren, W. H. Jr. | date=1991 | publisher=[[Centre de Données astronomiques de Strasbourg|CDS]] }} ID [http://vizier.u-strasbg.fr/viz-bin/Cat?V/50 V/50].</ref> Alpha Ophiuchi is composed of an A-type (bluish-white) giant star<ref name=aj74_375>{{citation | display-authors=1 | last1=Cowley | first1=A. | last2=Cowley | first2=C. | last3=Jaschek | first3=M. | last4=Jaschek | first4=C. | title=A study of the bright A stars. I. A catalogue of spectral classifications | journal=Astronomical Journal | volume=74 | pages=375–406 |date=April 1969 | doi=10.1086/110819 | bibcode=1969AJ.....74..375C }}</ref> and a [[K-type main sequence star]].<ref name=apj726_2_104>{{citation | display-authors=1 | last1=Hinkley | first1=Sasha | last2=Monnier | first2=John D. | last3=Oppenheimer | first3=Ben R. | last4=Roberts | first4=Lewis C. Jr. | last5=Ireland | first5=Michael | last6=Zimmerman | first6=Neil | last7=Brenner | first7=Douglas | last8=Parry | first8=Ian R. | last9=Martinache | first9=Frantz | title=Establishing α Oph as a Prototype Rotator: Improved Astrometric Orbit | journal=The Astrophysical Journal | volume=726 | issue=2 | page=104 |date=January 2011 | doi=10.1088/0004-637X/726/2/104 | bibcode=2011ApJ...726..104H |arxiv = 1010.4028 | s2cid=50830196 | url=http://authors.library.caltech.edu/21951/1/Hinkley2011p12486Astrophys_J.pdf }}</ref> The primary is a rapid rotator<ref name=monnierrasalhague>{{cite journal|doi=10.1088/0004-637X/725/1/1192|arxiv=1012.0787|title=Rotationally Modulated g-modes in the Rapidly Rotating δ Scuti Star Rasalhague (α Ophiuchi)|journal=The Astrophysical Journal|volume=725|issue=1|pages=1192–1201|year=2010|last1=Monnier|first1=J. D|last2=Townsend|first2=R. H. D|last3=Che|first3=X|last4=Zhao|first4=M|last5=Kallinger|first5=T|last6=Matthews|first6=J|last7=Moffat|first7=A. F. J|bibcode=2010ApJ...725.1192M|s2cid=51105576}}</ref> with an inclined axis of rotation.<ref name=rmaa38_117>{{citation | display-authors=1 | last1=Zhao | first1=M. | last2=Monnier | first2=J. D. | last3=Pedretti | first3=E. | last4=Thureau | first4=N. | last5=Mérand | first5=A. | last6=Ten Brummelaar | first6=T. | last7=McAlister | first7=H. | last8=Ridgway | first8=S. T. | last9=Turner | first9=N. | title=Imaging and Modeling Rapid Rotators: α Cep and α Oph | department=The Interferometric View on Hot Stars | editor1-first=Th. | editor1-last=Rivinius | editor2-first=M. | editor2-last=Curé | journal=Revista Mexicana de Astronomía y Astrofísica, Serie de Conferencias | volume=38 | pages=117–118 |date=February 2010 | bibcode=2010RMxAC..38..117Z }}</ref> Eta Ophiuchi is a binary system.<ref name=aj133_4_1209>{{citation | last1=Docobo | first1=J. A. | last2=Ling | first2=J. F. | title=Orbits and System Masses of 14 Visual Double Stars with Early-Type Components | journal=The Astronomical Journal | volume=133 | issue=4 | pages=1209–1216 |date=April 2007 | doi=10.1086/511070 | bibcode=2007AJ....133.1209D | s2cid=120821801 | doi-access=free }}</ref> Other bright stars in the constellation include [[Beta Ophiuchi|β Ophiuchi]], Cebalrai ("dog of the shepherd")<ref>{{cite book |author1=Paul Kunitzsch |author2=Tim Smart |title=A Dictionary of Modern Star Names: A Short Guide to 254&nbsp;Star Names and Their Derivations |url=https://books.google.com/books?id=XVspPwAACAAJ |year=2006 |publisher=[[Sky Publishing Corporation]] |isbn=978-1-931559-44-7 |page=44}}</ref> and [[Lambda Ophiuchi|λ Ophiuchi]], or Marfik ("the elbow").<ref>Chartrand, at p. 170.</ref> Beta Ophiuchi is an evolved [[red giant]] star that is slightly more massive than the Sun.<ref name=aaa352_555>{{citation | last1=Allende Prieto | first1=C. | last2=Lambert | first2=D. L. | title=Fundamental parameters of nearby stars from the comparison with evolutionary calculations: masses, radii and effective temperatures | journal=[[Astronomy and Astrophysics]] | volume=352| pages=555–562 | year=1999 | doi=10.1051/0004-6361/200811242 | bibcode=1999A&A...352..555A | arxiv=0809.0359 | s2cid=14531031 }}</ref><ref name=aaa480_1_91>{{citation | display-authors=1 | last1=Soubiran | first1=C. | last2=Bienaymé | first2=O. | last3=Mishenina | first3=T. V. | last4=Kovtyukh | first4=V. V. | title=Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants | journal=Astronomy and Astrophysics | year=2008 | volume=480 | issue=1 | pages=91–101 | bibcode=2008A&A...480...91S | doi=10.1051/0004-6361:20078788 |arxiv = 0712.1370 | s2cid=16602121 }}</ref> Lambda Ophiuchi is a binary star system with the primary being more massive and luminous than the Sun.<ref name=zorec2012>{{cite journal
 | last1=Zorec | first1=J. | last2=Royer | first2=F.
 | last3=Asplund | first3=Martin | last4=Cassisi | first4=Santi
 | last5=Ramirez | first5=Ivan | last6=Melendez | first6=Jorge
 | last7=Bensby | first7=Thomas | last8=Feltzing | first8=Sofia
 | title=Rotational velocities of A-type stars. IV. Evolution of rotational velocities
 | display-authors=1 | journal=Astronomy and Astrophysics
 | volume=537 | pages=A120 | year=2012
 | bibcode=2012A&A...537A.120Z | arxiv=1201.2052
 | doi=10.1051/0004-6361/201117691 | s2cid=55586789 }}</ref><ref name=aaa388>{{cite journal |author1=Lastennet, E. |author2=Fernandes, J. |author3=Lejeune, Th. | title=A revised HRD for individual components of binary systems from BaSeL BVRI synthetic photometry. Influence of interstellar extinction and stellar rotation | journal=Astronomy and Astrophysics | volume=388 | pages=309–319 |date=June 2002 | doi=10.1051/0004-6361:20020439 | bibcode=2002A&A...388..309L |arxiv = astro-ph/0203341 |s2cid=14376211 }}</ref>

[[RS Ophiuchi]] is part of a class called recurrent [[nova]]e, whose brightness increase at irregular intervals by hundreds of times in a period of just a few days. It is thought to be at the brink of becoming a type-1a [[supernova]].<ref>{{cite news |url=http://news.bbc.co.uk/2/hi/science/nature/5204676.stm |title=Star 'soon to become supernova' |publisher=[[BBC News]] |date=23 July 2006}}</ref> It erupts around every 15 years and usually has a magnitude of around 5.0 during eruptions, most recently in 2021.<ref>{{Cite web|title=[vsnet-alert 26131] Outburst of RS Ophiuchi|url=http://ooruri.kusastro.kyoto-u.ac.jp/mailarchive/vsnet-alert/26131|access-date=2021-08-09|website=ooruri.kusastro.kyoto-u.ac.jp}}</ref><ref>{{Cite web|title=ATel #14834: Fermi-LAT Gamma-ray Detection of the Recurrent Nova RS Oph|url=https://astronomerstelegram.org/?read=14834|access-date=2021-08-09|website=ATel}}</ref>

[[Barnard's Star]], one of the [[list of nearest stars|nearest stars]] to the [[Solar System]] (the only stars closer are the [[Alpha Centauri]] [[binary star]] system and [[Proxima Centauri]]), lies in Ophiuchus. It is located to the left of β and just north of the V-shaped group of stars in an area that was once occupied by the now-obsolete constellation of [[Taurus Poniatovii]] (Poniatowski's Bull). It is thought that an exoplanet orbits around the star,<ref name=BarnardPlanet>{{cite journal
          | last1   = Ribas                | first1   = I.
          | last2  = Tuomi                | first2  = M.
          | last3  = Reiners              | first3  = Ansgar
          | last4  = Butler               | first4  = R. P.
          | last5  = Morales              | first5  = J. C.
          | last6  = Perger               | first6  = M.
          | last7  = Dreizler             | first7  = S.
          | last8  = Rodríguez-López      | first8  = C.
          | last9  = González Hernández   | first9  = J. I.
          | last10 = Rosich               | first10 = A.
          | last11 = Feng                 | first11 = F.
          | last12 = Trifonov             | first12 = T.
          | last13 = Vogt                 | first13 = S. S.
          | last14 = Caballero            | first14 = J. A.
          | last15 = Hatzes               | first15 = A.
          | last16 = Herrero              | first16 = E.
          | last17 = Jeffers              | first17 = S. V.
          | last18 = Lafarga              | first18 = M.
          | last19 = Murgas               | first19 = F.
          | last20 = Nelson               | first20 = R. P.
          | last21 = Rodríguez            | first21 = E.
          | last22 = Strachan             | first22 = J. B. P.
          | last23 = Tal-Or               | first23 = L.
          | last24 = Teske                | first24 = J.
          | last25 = Toledo-Padrón        | first25 = B.
          | last26 = Zechmeister          | first26 = M.
          | last27 = Quirrenbach          | first27 = A.
          | last28 = Amado                | first28 = P. J.
          | last29 = Azzaro               | first29 = M.
          | last30 = Béjar                | first30 = V. J. S.
          | last31 = Barnes               | first31 = J. R.
          | last32 = Berdiñas             | first32 = Z. M.
          | last33 = Burt                 | first33 = J.
          | last34 = Coleman              | first34 = G.
          | last35 = Cortés-Contreras     | first35 = M.
          | last36 = Crane                | first36 = J.
          | last37 = Engle                | first37 = S. G.
          | last38 = Guinan               | first38 = E. F.
          | last39 = Haswell              | first39 = C. A.
          | last40 = Henning              | first40 = Th.
          | last41 = Holden               | first41 = B.
          | last42 = Jenkins              | first42 = J.
          | last43 = Jones                | first43 = H. R. A.
          | last44 = Kaminski             | first44 = A.
          | last45 = Kiraga               | first45 = M.
          | last46 = Kürster              | first46 = Martin
          | last47 = Lee                  | first47 = M. H.
          | last48 = López-González       | first48 = M. J.
          | last49 = Montes               | first49 = D.
          | last50 = Morin                | first50 = J.
          | last51 = Ofir                 | first51 = A.
          | last52 = Pallé                | first52 = E.
          | last53 = Rebolo               | first53 = Rafael
          | last54 = Reffert              | first54 = S.
          | last55 = Schweitzer           | first55 = A.
          | last56 = Seifert              | first56 = W.
          | last57 = Shectman             | first57 = S. A.
          | last58 = Staab                | first58 = D.
          | last59 = Street               | first59 = R. A.
          | last60 = Suárez Mascareño     | first60 = A.
          | last61 = Tsapras              | first61 = Y.
          | last62 = Wang                 | first62 = S. X.
          | last63 = Anglada-Escudé       | first63 = G.
          | display-authors    = 4
          | date              = 2018-11-14
          | title             = A candidate super-Earth planet orbiting near the snow line of Barnard's star
          | url               = https://www.eso.org/public/archives/releases/sciencepapers/eso1837/eso1837a.pdf
          | url-status        = live
          | journal           = [[Nature (journal)|Nature]]
          | publisher         = [[Holtzbrinck Publishing Group]]
          | volume            = 563
          | issue             = 7731
          | pages             = 365–368
          | arxiv             = 1811.05955
          | bibcode           = 2018Natur.563..365R
          | doi               = 10.1038/s41586-018-0677-y
          | issn              = 0028-0836
          | oclc              = 716177853
          | archive-url       = https://web.archive.org/web/20190326185022/https://www.eso.org/public/archives/releases/sciencepapers/eso1837/eso1837a.pdf
          | archive-date      = 2019-03-26
          | pmid              = 30429552
     | hdl = 2299/21132
 | s2cid = 256769911}}</ref>
but later studies have refuted this claim.<ref name=Lubin2021>{{cite journal | last1=Lubin | first1=Jack | last2=Robertson | first2=Paul | last3=Stefansson | first3=Gudmundur | last4=Ninan | first4=Joe | last5=Mahadevan | first5=Suvrath | last6=Endl | first6=Michael | last7=Ford | first7=Eric | last8=Wright | first8=Jason T. | last9=Beard | first9=Corey | last10=Bender | first10=Chad | last11=Cochran | first11=William D. | last12=Diddams | first12=Scott A. | last13=Fredrick | first13=Connor | last14=Halverson | first14=Samuel | last15=Kanodia | first15=Shubham | last16=Metcalf | first16=Andrew J. | last17=Ramsey | first17=Lawrence | last18=Roy | first18=Arpita | last19=Schwab | first19=Christian | last20=Terrien | first20=Ryan |display-authors=3 | title=Stellar Activity Manifesting at a One-year Alias Explains Barnard b as a False Positive | journal=The Astronomical Journal | publisher=American Astronomical Society | volume=162 | issue=2 | date=15 July 2021 | doi=10.3847/1538-3881/ac0057|issn=0004-6256 | pages=61 | arxiv=2105.07005| bibcode=2021AJ....162...61L | s2cid=234741985 | doi-access=free }}</ref> In 1998, an intense flare was observed.<ref name=PaulsonBarnard>{{cite journal|first1=Diane B.|last1=Paulson|year=2006|title=Optical Spectroscopy of a Flare on Barnard's Star|journal=[[Publications of the Astronomical Society of the Pacific]]|volume=118|issue=1|page=227|doi=10.1086/499497|last2=Allred|first2=Joel C.|last3=Anderson|first3=Ryan B.|last4=Hawley|first4=Suzanne L.|last5=Cochran|first5=William D.|last6=Yelda|first6=Sylvana|bibcode=2006PASP..118..227P|arxiv=astro-ph/0511281|s2cid=17926580}}</ref><ref name=BenedictBarnard>{{cite journal|last1=Benedict|first1=G. Fritz|year=1998|title=Photometry of Proxima Centauri and Barnard's star using Hubble Space Telescope fine guidance senso 3|journal=The Astronomical Journal|bibcode=1998AJ....116..429B|volume=116|issue=1|page=429|doi=10.1086/300420|last2=McArthur|first2=Barbara|last3=Nelan|first3=E.|last4=Story|first4=D.|last5=Whipple|first5=A. L.|last6=Shelus|first6=P. J.|last7=Jefferys|first7=W. H.|last8=Hemenway|first8=P. D.|last9=Franz|first9=Otto G.|last10=Wasserman|first10=L. H.|last11=Duncombe|first11=R. L.|last12=Van Altena|first12=W.|last13=Fredrick|first13=L. W.|arxiv=astro-ph/9806276|s2cid=15880053}}</ref> The star has also been a target of plans for interstellar travel such as [[Project Daedalus]].<ref name=Daedalus76>{{cite journal|last1=Bond|first1=A.|last2=Martin|first2=A. R.|name-list-style=amp|year=1976|title=Project Daedalus – The mission profile|journal=[[Journal of the British Interplanetary Society]]|url=http://md1.csa.com/partners/viewrecord.php?requester=gs&collection=TRD&recid=A7618970AH&q=project+daedalus&uid=788304424&setcookie=yes|volume=9|issue=2|page=101|access-date=15 August 2006|bibcode=1976JBIS...29..101B|url-status=dead|archive-url=https://web.archive.org/web/20071020144727/http://md1.csa.com/partners/viewrecord.php?requester=gs&collection=TRD&recid=A7618970AH&q=project+daedalus&uid=788304424&setcookie=yes|archive-date=20 October 2007}}</ref><ref name=DarlingDaedalus>{{cite encyclopedia|first=David|last=Darling|url=http://www.daviddarling.info/encyclopedia/D/Daedalus.html|title=Daedalus, Project|date=July 2005|encyclopedia=The Encyclopedia of Astrobiology, Astronomy, and Spaceflight|access-date=10 August 2006|archive-url=https://web.archive.org/web/20060831043940/http://www.daviddarling.info/encyclopedia/D/Daedalus.html|archive-date=31 August 2006|url-status=live}}</ref> In 2005, astronomers using data from the [[Green Bank Telescope]] discovered a [[superbubble]] so large that it extends beyond the plane of the galaxy.<ref name='huge superbubble'>{{cite news |title=Huge 'Superbubble' of Gas Blowing Out of Milky Way |date=13 January 2006 |url=http://www.physorg.com/news9882.html|work=[[PhysOrg.com]] |access-date=4 July 2008}}</ref> It is called the [[Ophiuchus Superbubble]].

In April 2007, [[astronomer]]s announced that the [[Sweden|Swedish]]-built [[Odin (satellite)|Odin satellite]] had made the first detection of clouds of [[molecule|molecular]] [[oxygen]] in space, following observations in the constellation Ophiuchus.<ref>{{cite web |url=https://www.sciencedaily.com/releases/2007/04/070417080835.htm |title=Molecular Oxygen Detected for the First Time in the Interstellar Medium |access-date=28 September 2016}}</ref> The [[SN 1604|supernova of 1604]] was first observed on 9&nbsp;October 1604, near θ&nbsp;Ophiuchi. [[Johannes Kepler]] saw it first on 16&nbsp;October and studied it so extensively that the [[supernova]] was subsequently called ''Kepler's Supernova''. He published his findings in a book titled ''De stella nova in pede Serpentarii'' (''On the New Star in Ophiuchus's Foot''). [[Galileo Galilei|Galileo]] used its brief appearance to counter the [[Aristotle|Aristotelian]] [[dogma]] that the heavens are changeless. It was a Type Ia supernova<ref name = "Reynolds2007">{{Cite journal | last1 = Reynolds | first1 = S. P. | last2 = Borkowski | first2 = K. J. | last3 = Hwang | first3 = U. | last4 = Hughes | first4 = J. P. | last5 = Badenes | first5 = C. | last6 = Laming | first6 = J. M. | last7 = Blondin | first7 = J. M. | date = 2 October 2007 | title = A Deep ''Chandra'' Observation of Kepler's Supernova Remnant: A Type Ia Event with Circumstellar Interaction | journal = [[The Astrophysical Journal]] | volume = 668 | issue = 2 | pages = L135–L138 | doi = 10.1086/522830 |doi-access=free|arxiv = 0708.3858 |bibcode = 2007ApJ...668L.135R |bibcode-access=free}}</ref> and the most recent Milky Way supernova visible to the unaided eye.<ref>{{cite web|title=Kepler's Supernova: Recently Observed Supernova|url=http://www.universeforfacts.com/2013/12/keplers-supernova-sn-1064-most-recently.html|archive-url=https://web.archive.org/web/20190104220659/http://www.universeforfacts.com/2013/12/keplers-supernova-sn-1064-most-recently.html|url-status=usurped|archive-date=4 January 2019|website=Universe for Facts|access-date=21 December 2014}}</ref> In 2009 it was announced that [[GJ 1214]], a star in Ophiuchus, undergoes repeated, cyclical dimming with a period of about 1.5&nbsp;days consistent with the transit of a small orbiting planet.<ref>{{cite journal |last1=Charbonneau |first1=David |display-authors=etal <!-- Zachory K. Berta, Jonathan Irwin, Christopher J. Burke, Philip Nutzman, Lars A. Buchhave, Christophe Lovis, Xavier Bonfils, David W. Latham, Stéphane Udry, Ruth A. Murray-Clay, Matthew J. Holman, Emilio E. Falco, Joshua N. Winn, Didier Queloz, Francesco Pepe, Michel Mayor, Xavier Delfosse, Thierry Forveille --> |title=A super-Earth transiting a nearby low-mass star |journal=Nature |volume=462 |issue=7275 |pages=891–894 |doi=10.1038/nature08679 |pmid=20016595 |date=December 2009 |arxiv=0912.3229 |bibcode=2009Natur.462..891C|s2cid=4360404 }}</ref> The planet's low density (about 40% that of Earth) suggests that the planet might have a substantial component of low-density gas—possibly [[hydrogen]] or [[steam]].<ref>{{cite journal |last1=Rogers |first1=Leslie A. |last2=Seager |first2=Sara |title=Three Possible Origins for the Gas Layer on GJ&nbsp;1214b |journal=The Astrophysical Journal |volume=716 |issue=2 |pages=1208–1216 |doi=10.1088/0004-637x/716/2/1208 |bibcode=2010ApJ...716.1208R |arxiv=0912.3243 |year=2010|s2cid=15288792 }}</ref> The proximity of this star to Earth (42&nbsp;light years) makes it a feasible target for further observations. The host star emits X-rays which could have removed mass from the exoplanet.<ref name=Lalitha2014>{{cite journal
 | title=X-Ray Emission from the Super-Earth Host GJ 1214
 | display-authors=1
 | last1=Lalitha | first1=S.
 | last2=Poppenhaeger | first2=K.
 | last3=Singh | first3=K. P.
 | last4=Czesla | first4=S.
 | last5=Schmitt | first5=J. H. M. M.
 | journal=The Astrophysical Journal Letters
 | volume=790
 | issue=1
 | id=L11
 | pages=5
 | date=July 2014
 | doi=10.1088/2041-8205/790/1/L11
 | bibcode=2014ApJ...790L..11L
 |arxiv = 1407.2741 | s2cid=118774018
 }}</ref> In April 2010, the naked-eye star [[Zeta Ophiuchi|ζ Ophiuchi]] was occulted by the asteroid [[824 Anastasia]].<ref>{{cite web |url=http://www.skyandtelescope.com/resources/proamcollab/astroalert/89599442.html |title=Asteroid To Hide Naked-Eye Star |access-date=2019-07-17 |date=31 March 2010 }}</ref><ref>{{cite web |url=http://www.skyandtelescope.com/observing/highlights/89690067.html |title=Asteroid To Hide Bright Star |access-date=2019-07-17|date=31 March 2010 }}</ref><ref name=IOTA>{{cite web |url=http://asteroidoccultation.com/2010_04_si.htm |title=(824) Anastasia / HIP 81377 event on 2010 Apr&nbsp;06, 10:21&nbsp;UT |access-date=2019-07-17 |archive-date=17 July 2019 |archive-url=https://web.archive.org/web/20190717141423/http://asteroidoccultation.com/2010_04_si.htm |url-status=dead }}</ref>

<gallery widths="140px" heights="200px">
Image:OphiuchusCC.jpg|The constellation Ophiuchus as it can be seen by naked eye.<ref>{{cite web |url=http://www.allthesky.com/constellations/ophiuchus.html |title=Ophiuchus, the Serpent Bearer – Constellations – Digital Images of the Sky. |website=allthesky.com}}</ref>
File:Aratea 10v.jpg|Illustration of [[Serpens]], Ophiuchus and [[Scorpius]] in the [[Leiden Aratea]] manuscript, around 830 - 840.
Image:Stjärnbild på Herkules, 1602 - Skoklosters slott - 102426.tif|Hercules and Ophiuchus, 1602, by [[Willem Blaeu]].
File:Kepler De Stella Nova.jpg|[[Johannes Kepler]]'s 1606 book ''De Stella Nova in Pede Serpentarii'' (On the New Star in Ophiuchus's Foot) opened at the page for Ophiuchus.
Image:Kepler Drawing of SN 1604.png|Detail showing the ''stella nova'' marked "N" in the right foot of Ophiuchus.
</gallery>