View source for Corona Borealis

{{short description|Constellation in the northern celestial hemisphere}}
{{redirect|Northern Crown|the d20 System game|Northern Crown (roleplaying game)}}
{{featured article}}
{{Infobox constellation
| name = Corona Borealis
| abbreviation = CrB
| genitive = Coronae Borealis
| pronounce = {{IPAc-en|k|ə|ˈ|r|oʊ|n|ə|_|ˌ|b|ɔːr|i|ˈ|æ|l|ᵻ|s|,_|-|ˌ|b|oʊ|-|,_|-|ˈ|eɪ|l|ᵻ|s}} {{respell|kə|ROH|nə|_|bor|ee|AL|iss|,_|-|boh|-|,_|-|AY|liss}}, genitive {{IPAc-en|k|ə|ˈ|r|oʊ|n|i}} {{respell|kə|ROH|nee}}<ref>{{MerriamWebsterDictionary|Corona}}, {{MerriamWebsterDictionary|Corona Borealis}}.</ref><ref>{{Dictionary.com|Corona Borealis}}</ref>
| symbolism = The [[North]]ern [[Crown (headgear)|Crown]]
| RA = {{RA|15|16|03.8205}}–{{RA|16|25|07.1526}}<ref name=boundary>{{Cite journal | title=Corona Borealis, constellation boundary | journal=The Constellations | publisher=International Astronomical Union |url=https://www.iau.org/public/themes/constellations/#crb | access-date=27 February 2014 }}</ref>
| dec= {{dec|39.7117195}}–{{dec|25.5380573}}<ref name=boundary/>
| family = [[Ursa Major Family|Ursa Major]]
| areatotal = 179
| arearank = 73rd
| numbermainstars = 7
| numberbfstars = 24
| numberbrightstars = 1
| numbernearbystars = 0
| brighteststarname = [[Alpha Coronae Borealis|α CrB]] (Alphecca or Gemma)
| starmagnitude = 2.21
| neareststarname = [[LSPM J1524+2925]]<ref name=Kirkpatrick2024/>{{rp|84}}
| stardistancely = 42.65
| stardistancepc = 13.08
| numbermessierobjects = 0
| meteorshowers = None
| bordering =
  {{plainlist |
* [[Hercules (constellation)|Hercules]]
* [[Boötes]]
* [[Serpens|Serpens Caput]]
  }}
| latmax = [[North Pole|90]]
| latmin = [[50th parallel south|50]]
| month = June
| notes =
}}

'''Corona Borealis''' is a small [[constellation]] in the [[Northern Celestial Hemisphere]]. It is one of the 48&nbsp;constellations listed by the 2nd-century astronomer [[Ptolemy]], and remains one of the [[88 modern constellations]]. Its brightest [[star]]s form a semicircular arc. Its Latin name, inspired by its shape, means "northern crown".  In [[classical mythology]] Corona Borealis generally represented the crown given by the god [[Dionysus]] to the Cretan princess [[Ariadne]] and set by her in the heavens. Other cultures likened the pattern to a circle of elders, an eagle's nest, a bear's den or a smokehole. Ptolemy also listed a southern counterpart, [[Corona Australis]], with a similar pattern.

The brightest star is the [[apparent magnitude|magnitude]]&nbsp;2.2 [[Alpha Coronae Borealis]]. The yellow supergiant [[R Coronae Borealis]] is the prototype of a rare class of giant stars—the [[R Coronae Borealis variable]]s—that are extremely hydrogen deficient, and thought to result from the merger of two white dwarfs. [[T Coronae Borealis]], also known as the Blaze Star, is another unusual type of variable star known as a [[recurrent nova]]. Normally of magnitude&nbsp;10, it last flared up to magnitude&nbsp;2 in 1946, and is predicted to do the same in 2025. [[ADS 9731]] and [[Sigma Coronae Borealis]] are multiple star systems with six and five components respectively. Five stars in the constellation host [[Jupiter]]-sized [[exoplanet]]s. [[Abell 2065]] is a highly concentrated [[galaxy cluster]] one billion light-years from the Solar System containing more than 400 members, and is itself part of the larger [[Corona Borealis Supercluster]].

== Characteristics ==
Covering 179 square degrees and hence 0.433% of the sky, Corona Borealis ranks 73rd of the [[IAU designated constellations]] by area.<ref name=tirionconst/> Its position in the [[Northern Celestial Hemisphere]] means that the whole [[constellation]] is visible to observers north of [[50th parallel south|50°S]].<ref name=tirionconst>{{cite web| url=http://www.ianridpath.com/constellations1.html | title=Constellations: Andromeda–Indus | work= Star Tales |author=Ridpath, Ian|publisher=self-published | access-date= 9 September 2014| author-link=Ian Ridpath }}</ref>{{efn|1=While parts of the constellation technically rise above the horizon to observers between the 50°S and [[64th parallel south|64°S]], stars within a few degrees of the horizon are to all intents and purposes unobservable.<ref name=tirionconst/>}} It is bordered by [[Boötes]] to the north and west, [[Serpens|Serpens Caput]] to the south, and [[Hercules (constellation)|Hercules]] to the east. The three-letter abbreviation for the constellation, as adopted by the [[International Astronomical Union]] in 1922, is "CrB".<ref name="pa30_469">{{cite journal | last=Russell | first=Henry Norris |author-link=Henry Norris Russell | title=The New International Symbols for the Constellations | journal=[[Popular Astronomy (US magazine)|Popular Astronomy]] | volume=30 | page=469 | bibcode=1922PA.....30..469R | year=1922 }}</ref> The official constellation boundaries, as set by Belgian astronomer [[Eugène Joseph Delporte|Eugène Delporte]] in 1930, are defined by a polygon of eight segments (''illustrated in infobox''). In the [[equatorial coordinate system]], the [[right ascension]] coordinates of these borders lie between {{RA|15|16.0}} and {{RA|16|25.1}}, while the [[declination]] coordinates are between 39.71° and 25.54°.<ref name="boundary2">{{Cite journal | title=Corona Borealis, Constellation Boundary | journal=The Constellations | publisher=International Astronomical Union | url=https://www.iau.org/public/themes/constellations/#crb | access-date=12 October 2013 }}</ref> It has a counterpart—[[Corona Australis]]—in the [[Southern Celestial Hemisphere]].<ref>{{cite book|last=Cornelius|first=Geoffrey|title=Complete Guide to the Constellations: The Starwatcher's Essential Guide to the 88 Constellations, Their Myths and Symbols|publisher=Duncan Baird Publishers|location=London, United Kingdom|date=2005|pages=70–71|isbn=978-1-84483-103-6}}</ref>

== Features ==

=== Stars ===
{{see also|List of stars in Corona Borealis}}
The seven stars that make up the constellation's distinctive crown-shaped pattern are all 4th-magnitude stars except for the brightest of them, [[Alpha Coronae Borealis]]. The other six stars are [[Theta Coronae Borealis|Theta]], [[Beta Coronae Borealis|Beta]], [[Gamma Coronae Borealis|Gamma]], [[Delta Coronae Borealis|Delta]], [[Epsilon Coronae Borealis|Epsilon]] and [[Iota Coronae Borealis]]. The German cartographer [[Johann Bayer]] gave twenty stars in Corona Borealis [[Bayer designation]]s from Alpha to Upsilon in his 1603 [[star atlas]] ''[[Uranometria]]''. Zeta Coronae Borealis was noted to be a double star by later astronomers and its components designated [[Zeta1 Coronae Borealis|Zeta<sup>1</sup>]] and [[Zeta2 Coronae Borealis|Zeta<sup>2</sup>]]. [[John Flamsteed]] did likewise with Nu Coronae Borealis; classed by Bayer as a single star, it was noted to be two close stars by Flamsteed. He named them 20 and 21 Coronae Borealis in [[Flamsteed designation|his catalogue]], alongside the designations [[Nu1 Coronae Borealis|Nu<sup>1</sup>]] and [[Nu2 Coronae Borealis|Nu<sup>2</sup>]] respectively.<ref name=wagman>{{cite book  | last = Wagman  | first = Morton  | year = 2003  | title = Lost Stars: Lost, Missing and Troublesome Stars from the Catalogues of Johannes Bayer, Nicholas Louis de Lacaille, John Flamsteed, and Sundry Others | publisher = The McDonald & Woodward Publishing Company | location = Blacksburg, Virginia | isbn = 978-0-939923-78-6 |pages=117–18}}</ref> Chinese astronomers deemed nine stars to make up the asterism, adding [[Pi Coronae Borealis|Pi]] and [[Rho Coronae Borealis]].<ref name=ridpathCB>{{cite web| url=http://www.ianridpath.com/startales/coronaborealis.html#chinese | title=Corona Borealis |last1=Ridpath|first1=Ian|publisher=self-published  |work=Star Tales | access-date= 24 November 2014}}</ref> Within the constellation's borders, there are 37 stars brighter than or equal to [[apparent magnitude]]&nbsp;6.5.{{efn|1=Objects of magnitude 6.5 are among the faintest visible to the unaided eye in suburban-rural transition night skies.<ref>{{cite web|url=http://www.skyandtelescope.com/resources/darksky/3304011.html?page=1&c=y|title=The Bortle Dark-Sky Scale|last=Bortle|first=John E.|date=February 2001|work=[[Sky & Telescope]]|access-date=29 November 2014|archive-date=31 March 2014|archive-url=https://web.archive.org/web/20140331202746/http://www.skyandtelescope.com/resources/darksky/3304011.html?page=1&c=y|url-status=dead}}</ref>}}<ref name=tirionconst/>

[[File:CoronaBorealisCC.jpg|thumb|left|The constellation Corona Borealis as it can be seen by the naked eye]]
Alpha Coronae Borealis (officially named Alphecca by the IAU, but sometimes also known as Gemma) appears as a blue-white star of magnitude&nbsp;2.2.<ref>{{cite journal
 | author=Johnson, H. L.
 | author2=Iriarte, B.
 | author3=Mitchell, R. I.
 | author4=Wisniewskj, W. Z.
 | title=UBVRIJKL photometry of the bright stars
 | journal=Communications of the Lunar and Planetary Laboratory | volume=4 | issue=99 | pages=99
 | date=1966
 | bibcode=1966CoLPL...4...99J }}</ref> In fact, it is an [[Algol]]-type [[Binary star#eclipsing binaries|eclipsing binary]] that varies by 0.1&nbsp;magnitude with a period of 17.4&nbsp;days.{{sfn|Ridpath|Tirion|2001|pp=126–28}} The primary is a [[A-type main-sequence star|white main-sequence star]] of [[Stellar classification#Spectral types|spectral type]] A0V that is 2.91&nbsp;times the [[mass of the Sun]] ({{Solar mass|link=y}}) and 57 times as [[luminosity|luminous]] ({{Solar luminosity|link=y}}), and is surrounded by a [[debris disk]] out to a radius of around 60&nbsp;[[astronomical unit]]s (AU).<ref name="Pawellek 2014">{{cite journal|author1=Pawellek, Nicole |author2=Krivov, Alexander V. |author3=Marshall, Jonathan P. |author4=Montesinos, Benjamin |author5=Ábrahám, Péter |author6=Moór, Attila |author7=Bryden, Geoffrey |author8=Eiroa, Carlos |date=2014|title=Disk Radii and Grain Sizes in Herschel-resolved Debris Disks|journal=The Astrophysical Journal|volume=792|issue=1|id=65|pages=19|bibcode=2014ApJ...792...65P | doi=10.1088/0004-637X/792/1/65|arxiv = 1407.4579 |s2cid=119282523 }}</ref> The secondary companion is a [[G-type main-sequence star|yellow main-sequence star]] of spectral type G5V that is a little smaller (0.9 times) the diameter of the Sun.<ref name="aaa403">{{cite journal |author1=Güdel, M. |author2=Arzner, K. |author3=Audard, M. |author4=Mewe, R. | title=Tomography of a Stellar X-ray Corona: Alpha Coronae Borealis | journal=Astronomy and Astrophysics | volume=403 | pages=155–71 |date=2003 | doi=10.1051/0004-6361:20030257 | bibcode=2003A&A...403..155G| doi-access=free | url=https://www.dora.lib4ri.ch/psi/islandora/object/psi%3A53864/datastream/PDF/G%C3%BCdel-2003-Tomography_of_a_stellar_X-ray_corona-%28published_version%29.pdf }}</ref> Lying 75±0.5&nbsp;[[light-year]]s from Earth,<ref name="vanLeeuwen2007">{{cite journal | first=F. | last=van Leeuwen | title=Validation of the New Hipparcos Reduction | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–64 | date=2007 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 | arxiv=0708.1752| s2cid=18759600 }}</ref> Alphecca is believed to be a member of the [[Ursa Major Moving Group]] of stars that have a common motion through space.<ref>{{cite journal |author1=King, Jeremy R. |author2=Villarreal, Adam R. |author3=Soderblom, David R. |author4=Gulliver, Austin F. |author5=Adelman, Saul J. | title=Stellar Kinematic Groups. II. A Reexamination of the Membership, Activity, and Age of the Ursa Major Group | journal=The Astronomical Journal | volume=125 | issue=4 | pages=1980–2017 |date=2003  | doi=10.1086/368241 | bibcode=2003AJ....125.1980K| doi-access=free | url=https://tigerprints.clemson.edu/cgi/viewcontent.cgi?article=1248&context=physastro_pubs | url-access=subscription }}</ref>

Located 112±3&nbsp;light-years away,<ref name="vanLeeuwen2007"/> [[Beta Coronae Borealis]] or Nusakan is a [[spectroscopic binary]] system whose two components are separated by 10&nbsp;AU and orbit each other every 10.5 years.<ref name=kalerbeta>{{cite web| first1=James B. | last1=Kaler | title=Nusakan | work=Stars | publisher=University of Illinois | url=http://stars.astro.illinois.edu/sow/nusakan.html | access-date=12 November 2014}}</ref> The brighter component is a [[rapidly oscillating Ap star]],<ref name="The radius and effective temperatur">{{cite journal|author1=Bruntt, H. |author2=Kervella, P. |author3=Mérand, A. |author4=Brandão, I.M. |author5=Bedding, T.R. |author6=ten Brummelaar, T.A. |author7=Coudé du Foresto, V. |author8=Cunha, M. S. |author9=Farrington, C. |author10=Goldfinger, P.J. |author11=Kiss, L.L. |author12=McAlister, H.A. |author13=Ridgway, S.T. |author14=Sturmann, J. |author15=Sturmann, L. |author16=Turner, N. |author17=Tuthill, P.G. |date=2010|title=The radius and effective temperature of the binary Ap star β CrB from CHARA/FLUOR and VLT/NACO observations|journal=Astronomy and Astrophysics|volume=512|pages=7|id=A55|bibcode=2010A&A...512A..55B|doi=10.1051/0004-6361/200913405|arxiv = 0912.3215 |s2cid=14468327 }}</ref> pulsating with a period of 16.2&nbsp;minutes. Of spectral type A5V with a [[effective temperature|surface temperature]] of around 7980&nbsp;K, it has around {{Solar mass|2.1|link=y}}, 2.6&nbsp;[[solar radius|solar radii]] ({{Solar radius|link=y}}), and {{Solar luminosity|25.3|link=y}}. The smaller star is of spectral type F2V with a surface temperature of around 6750&nbsp;K, and has around {{Solar mass|1.4}}, {{Solar radius|1.56}}, and between 4 and {{Solar luminosity|5}}.<ref name="The radius and effective temperatur"/> Near Nusakan is [[Theta Coronae Borealis]], a binary system that shines with a combined magnitude of 4.13 located 380±20 light-years distant.<ref name="vanLeeuwen2007"/> The brighter component, Theta Coronae Borealis A, is a blue-white star that spins extremely rapidly—at a rate of around 393&nbsp;km per second. A [[Be star]], it is surrounded by a debris disk.<ref name=kalerthet>{{cite web| first1=James B. | last1=Kaler | title=Theta Coronae Borealis | work=Stars | publisher=University of Illinois | url=http://stars.astro.illinois.edu/sow/thetacrb.html | access-date=12 November 2014}}</ref>

Flanking Alpha to the east is Gamma Coronae Borealis, yet another binary star system, whose components orbit each other every 92.94&nbsp;years and are roughly as far apart from each other as the Sun and Neptune.<ref name=kalergamma>{{cite web| first1=James B. | last1=Kaler | title=Gamma Coronae Borealis | work=Stars | publisher=University of Illinois | url=http://stars.astro.illinois.edu/sow/gammacrb.html | access-date=18 November 2014 | date = 25 July 2008}}</ref> The brighter component has been classed as a [[Delta Scuti variable]] star,<ref name=SIMBADgamma>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=+Gamma+Coronae+Borealis&submit=SIMBAD+search |title = Gamma Coronae Borealis |work = SIMBAD Astronomical Database |publisher = Centre de Données astronomiques de Strasbourg |access-date = 21 November 2014}}</ref> though this view is not universal.<ref name=kalergamma/> The components are main sequence stars of spectral types B9V and A3V.<ref>{{cite journal|author1=Malkov, O. Yu. |author2=Tamazian, V.S. |author3=Docobo, J. A. |author4=Chulkov, D. A. |date=2012|title=Dynamical Masses of a Selected Sample of Orbital Binaries |journal=Astronomy & Astrophysics |volume=546|id=A69 |pages=5|doi=10.1051/0004-6361/201219774 | bibcode =2012A&A...546A..69M|doi-access=free }}</ref> Located 170±2&nbsp;light-years away,<ref name="vanLeeuwen2007"/> 4.06-magnitude [[Delta Coronae Borealis]] is a yellow giant star of spectral type G3.5III that is around {{Solar mass|2.4}} and has swollen to {{Solar radius|7.4}}. It has a surface temperature of 5180&nbsp;K.<ref name="Gondoin">{{cite journal|last=Gondoin|first=P.|date=2005|title=The X-ray activity of the slowly rotating G giant δ CrB|journal=Astronomy & Astrophysics|volume=431|issue=3|pages=1027–35|  doi= 10.1051/0004-6361:20041991 | bibcode = 2005A&A...431.1027G
|doi-access=free}}</ref>  For most of its existence, Delta Coronae Borealis was a [[B-type main-sequence star|blue-white main-sequence star]] of spectral type B before it ran out of hydrogen fuel in its core. Its luminosity and spectrum suggest it has just crossed the [[Hertzsprung gap]], having finished burning core hydrogen and just begun burning hydrogen in a shell that surrounds the core.<ref name=kalerdelta>{{cite web| first1=James B. | last1=Kaler | title=Delta Coronae Borealis | work=Stars | publisher=University of Illinois | url=http://stars.astro.illinois.edu/sow/deltacrb.html | access-date=21 November 2014}}</ref>

[[Zeta Coronae Borealis]] is a double star with two blue-white components 6.3&nbsp;[[Minute of arc|arcseconds]] apart that can be readily separated at 100x&nbsp;[[magnification#Telescope|magnification]]. The primary is of magnitude&nbsp;5.1 and the secondary is of magnitude&nbsp;6.0.<ref>{{cite book|author1=Kepple, George Robert |author2=Sanner, Glen W. |title=The Night Sky Observers Guide: Spring & summer|publisher=Willmann-Bell|location=Richmond, Virginia|date=1998|pages=111|isbn=978-0-943396-60-6}}</ref> [[Nu Coronae Borealis]] is an [[Double star|optical double]], whose components are a similar distance from Earth but have different [[radial velocity|radial velocities]], hence are assumed to be unrelated.<ref name=kalernu>{{cite web| first1=James B. | last1=Kaler | title=Nu Coronae Borealis | work=Stars | publisher=University of Illinois | url=http://stars.astro.illinois.edu/sow/nucrb.html | access-date=13 November 2014|date=31 August 2007}}</ref> The primary, [[Nu1 Coronae Borealis|Nu<sup>1</sup> Coronae Borealis]], is a [[red giant]] of spectral type M2III and magnitude 5.2, lying 640±30 light-years distant,<ref name="vanLeeuwen2007"/><ref name=SIMBADnu1>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+147749&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id |title = Nu1 Coronae Borealis |work = SIMBAD Astronomical Database |publisher = Centre de Données astronomiques de Strasbourg |access-date = 13 November 2014}}</ref> and the secondary, [[Nu2 Coronae Borealis|Nu<sup>2</sup> Coronae Borealis]], is an orange-hued giant star of spectral type K5III and magnitude 5.4, estimated to be 590±30&nbsp;light-years away.<ref name="vanLeeuwen2007"/><ref name=SIMBADnu2>{{cite web |url = http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+147767&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id |title = Nu2 Coronae Borealis |work = SIMBAD Astronomical Database |publisher = Centre de Données astronomiques de Strasbourg |access-date = 13 November 2014}}</ref> [[Sigma Coronae Borealis]], on the other hand, is a true multiple star system divisible by small amateur telescopes.{{sfn|Ridpath|Tirion|2001|pp=126–28}} It is actually a complex system composed of two stars around as massive as the Sun that orbit each other every 1.14&nbsp;days, orbited by a third Sun-like star every 726&nbsp;years. The fourth and fifth components are a binary [[red dwarf]] system that is 14,000&nbsp;AU distant from the other three stars.<ref name="Raghavan 2009">{{cite journal|author1=Raghavan, Deepak |author2=McAlister, Harold A. |author3=Torres, Guillermo |author4=Latham, David W. |author5=Mason, Brian D. |author6=Boyajian, Tabetha S. |author7=Baines, Ellyn K. |author8=Williams, Stephen J. |author9=ten Brummelaar, Theo A. |author10=Farrington, Chris D. |author11=Ridgway, Stephen T. |author12=Sturmann, Laszlo |author13=Sturmann, Judit |author14=Turner, Nils H. |date=2009|title= The Visual Orbit of the 1.1 Day Spectroscopic Binary σ2 Coronae Borealis from Interferometry at the Chara Array|journal=The Astrophysical Journal|volume=690|issue=1|pages=394–406|doi=10.1088/0004-637X/690/1/394 | bibcode=2009ApJ...690..394R|arxiv = 0808.4015 |s2cid=14638405 }}</ref> [[ADS 9731]] is an even rarer multiple system in the constellation, composed of six stars, two of which are spectroscopic binaries.<ref name=Tokovinin>{{cite journal|bibcode=1998AstL...24..795T|title=ADS 9731: A new sextuple system|last1=Tokovinin |first1=A.A.|last2=Shatskii|first2=N.I.|last3=Magnitskii|first3=A.K.|volume=24|issue=6|year=1998|pages=795–801|journal=[[Astronomy Letters]]}}</ref>{{efn|1=The components are organised thus: Aa and Ab are yellow-white main sequence stars of spectral types F4V and F5V and 1.35 and 1.32&nbsp;solar masses respectively, which orbit each other every 3.27 days. This pair is in a 450-year orbit with star B, a star of spectral type G4V that has around the same mass as the Sun. Star C is a yellow white star of spectral type F3V around 1.41&nbsp;times as massive as the Sun, which has just started brightening and moving off the main sequence. It is in a 1000-year orbit with a pair of stars, Da and Db, a yellow-white main sequence star of spectral type F7V and a red dwarf of spectral type M3V. Da and Db take 14.28&nbsp;days to orbit each other. Finally the system of stars C and Dab, and the system of stars Aab and B, take more than 20,000&nbsp;years to orbit each other.<ref name=Tokovinin/>}}

Corona Borealis is home to two remarkable [[Variable star|variable]] stars.<ref name="Levy 1998">{{cite book|last=Levy|first=David H.|title=Observing Variable Stars: A Guide for the Beginner|publisher=Cambridge University Press|location=Cambridge, United Kingdom|date=1998|pages=142–43|isbn=978-0-521-62755-9|url=https://books.google.com/books?id=5-O2cd937FMC&pg=PA142}}</ref> [[T Coronae Borealis]] is a [[cataclysmic variable star]] also known as the Blaze Star.{{sfn|Ridpath|Tirion|2001|pp=126–128}} Normally placid around magnitude 10—it has a minimum of 10.2 and maximum of 9.9—it brightens to magnitude 2 in a period of hours, caused by a [[nuclear reaction]] and the subsequent explosion. T Coronae Borealis is one of a handful of stars called [[recurrent nova]]e, which include [[T Pyxidis]] and [[U Scorpii]]. An outburst of T Coronae Borealis was first recorded in 1866; its second recorded outburst was in February 1946.<ref name=Schaefer2009>{{Cite journal|last=Schaefer |first=Bradley E.
  |title=Comprehensive Photometric Histories of All Known Galactic Recurrent Novae
  |journal=The Astrophysical Journal Supplement Series
  |volume=187
  |issue=2
  |pages=275–373
  |year=2010
  |arxiv=0912.4426 |doi=10.1088/0067-0049/187/2/275
  |bibcode = 2010ApJS..187..275S |s2cid=119294221
 }}</ref><ref name=Sanford1949>{{cite journal
  |last=Sanford |first=Roscoe F.
  |title=High-Dispersion Spectrograms of T Coronae Borealis.
  |journal=Astrophysical Journal
  |volume=109 |pages=81 |year=1949
  |doi=10.1086/145106
  |bibcode=1949ApJ...109...81S|doi-access=
  }}</ref> T Coronae Borealis started dimming in March 2023 and it is known that before it goes nova it dims for about a year; for this reason it was initially expected to go nova at any time between March and September, 2024.<ref>{{Cite news 
 | first = Mia
 | last = Taylor
 | author-link =
 | author = 
 | author2 =
 | title = Move over, solar eclipse: Scientists predict a once-in-a-lifetime nova explosion in the coming months
 | url = https://www.bbc.com/future/article/20240322-visible-nova-explosion-is-coming#_msocom_1
 | format = 
 | work = 
 | publisher = BBC
 | pages = 
 | page = 
 | date = March 22, 2024
 | access-date = March 23, 2024
 | language = English
 | quote = There's another sign that T CrB is getting ready to blow also, Cooke says. 'We know that before it goes nova it dims for about a year, and T Coronae Borealis started dimming back in March 2023, so that's why we think it's going to go nova between now and the end of September.' As of March 2025, the star has not yet gone nova. 
}}</ref> T Coronae Borealis is a [[binary star]] with a red-hued giant primary and a [[white dwarf]] secondary, the two stars orbiting each other over a period of approximately 8 months.<ref>{{cite book | last = Levy | first = David H. | year = 2005 | title = Deep Sky Objects | pages = [https://archive.org/details/deepskyobjects00davi/page/70 70–71] | publisher = Prometheus Books | location = Amherst, New York | isbn = 978-1-59102-361-6 | url = https://archive.org/details/deepskyobjects00davi/page/70 }}</ref> [[R Coronae Borealis]] is a yellow-hued variable [[supergiant]] star, over 7000 light-years from Earth, and prototype of a class of stars known as [[R Coronae Borealis variable]]s. Normally of magnitude 6, its brightness periodically drops as low as magnitude 15 and then slowly increases over the next several months.<ref>{{cite web| author=Davis, Kate|date= January 2000 |url=http://www.aavso.org/vsots_rcrb |title= R Coronae Borealis | work=Variable star of the season | publisher= American Association of Variable Star Observers (AAVSO) |access-date=14 March 2015}}</ref> These declines in magnitude come about as dust that has been ejected from the star obscures it. Direct imaging with the [[Hubble Space Telescope]] shows extensive dust clouds out to a radius of around 2000&nbsp;AU from the star, corresponding with a stream of fine dust (composed of grains 5&nbsp;[[nanometre|nm]] in diameter) associated with the star's stellar wind and coarser dust (composed of grains with a diameter of around 0.14&nbsp;[[micrometre|μm]]) ejected periodically.<ref>{{cite journal|author1=Jeffers, S. V. |author2=Min, M. |author3=Waters, L. B. F. M. |author4=Canovas, H. |author5=Rodenhuis, M. |author6=de Juan Ovelar, M. |author7=Chies-Santos, A. L. |author8=Keller, C. U. |date=2012|title=Direct imaging of a massive dust cloud around R Coronae Borealis|journal=Astronomy & Astrophysics|volume=539|issue=A56|pages=A56|bibcode=2012A&A...539A..56J |doi=10.1051/0004-6361/201117138|arxiv = 1203.1265 |s2cid=55589182 }}</ref>

There are several other variables of reasonable brightness for amateur astronomer to observe, including three [[Mira variable|Mira-type]] long period variables:<ref name="Levy 1998"/> [[S Coronae Borealis]] ranges between magnitudes 5.8 and 14.1 over a period of 360&nbsp;days.<ref name="AAVSOS">{{cite web|url=http://www.aavso.org/vsx/index.php?view=detail.top&oid=10601 |title=S Coronae Borealis|author=Watson, Christopher|date=4 January 2010|work=The International Variable Star Index|publisher=American Association of Variable Star Observers |access-date=25 September 2014}}</ref> Located around 1946&nbsp;light-years distant, it shines with a luminosity 16,643&nbsp;times that of the Sun and has a surface temperature of 3033 K.<ref name=Mcdonald>{{cite journal|author=McDonald, I.|author2=Zijlstra, A. A.|author3=Boyer, M.L.|date=2012|title=Fundamental Parameters and Infrared Excesses of Hipparcos Stars|journal=Monthly Notices of the Royal Astronomical Society|volume=427|issue=1|pages=343–57|bibcode=2012MNRAS.427..343M|doi=10.1111/j.1365-2966.2012.21873.x|doi-access=free |arxiv = 1208.2037 |s2cid=118665352}}</ref> One of the reddest stars in the sky,<ref name="Levy 1998"/> [[V Coronae Borealis]] is a cool star with a surface temperature of 2877&nbsp;K that shines with a luminosity 102,831 times that of the Sun and is a remote 8810&nbsp;light-years distant from Earth.<ref name=Mcdonald/> Varying between magnitudes 6.9 and 12.6 over a period of 357&nbsp;days,<ref name="AAVSOV">{{cite web|url=http://www.aavso.org/vsx/index.php?view=detail.top&oid=10604 |title=V Coronae Borealis|author=Watson, Christopher|date=4 January 2010|work=The International Variable Star Index |publisher=American Association of Variable Star Observers|access-date=13 November 2014}}</ref> it is located near the junction of the border of Corona Borealis with Hercules and Bootes.<ref name="Levy 1998"/> Located 1.5° northeast of [[Tau Coronae Borealis]], [[W Coronae Borealis]] ranges between magnitudes 7.8 and 14.3 over a period of 238&nbsp;days.<ref name="AAVSOW">{{cite web|url=http://www.aavso.org/vsx/index.php?view=detail.top&oid=10605 |title=W Coronae Borealis|author=Watson, Christopher|date=4 January 2010|work=The International Variable Star Index|publisher=American Association of Variable Star Observers|access-date=9 March 2015}}</ref> Another red giant, [[RR Coronae Borealis]] is a [[stellar classification|M3-type]] [[semiregular variable star]] that varies between magnitudes 7.3 and 8.2 over 60.8 days.<ref name=AAVSORR>{{cite web|url=http://www.aavso.org/vsx/index.php?view=detail.top&oid=10609 |title=RR Coronae Borealis|author =Otero, Sebastian Alberto |date=15 August 2011 |work=The International Variable Star Index |publisher=American Association of Variable Star Observers|access-date=25 September 2014}}</ref> [[RS Coronae Borealis]] is yet another semiregular variable red giant, which ranges between magnitudes 8.7 to 11.6  over 332 days.<ref name=AAVSORS>{{cite web|url=http://www.aavso.org/vsx/index.php?view=detail.top&oid=10610 |title=RS Coronae Borealis|author =Watson, Christopher |date=4 January 2010 |work=The International Variable Star Index|publisher=American Association of Variable Star Observers|access-date=25 July 2015}}</ref>  It is unusual in that it is a red star with a high proper motion (greater than 50 milliarcseconds a year).<ref name=" Jiménez-Esteban">{{cite journal|author1=Jiménez-Esteban, F. M. |author2=Caballero, J. A. |author3=Dorda, R. |author4=Miles-Páez, P. A. |author5=Solano, E. |date=2012|title=Identification of red high proper-motion objects in Tycho-2 and 2MASS catalogues using Virtual Observatory tools|journal=Astronomy & Astrophysics|volume=539|pages=12|doi=10.1051/0004-6361/201118375 |bibcode=2012A&A...539A..86J|arxiv = 1201.5315 |s2cid=53404166 }}</ref> Meanwhile, [[U Coronae Borealis]] is an Algol-type eclipsing binary star system whose magnitude varies between 7.66 and 8.79 over a period of 3.45 days<ref name="AAVSOU">{{cite web|url=http://www.aavso.org/vsx/index.php?view=detail.top&oid=10603 |title=U Coronae Borealis|author=Watson, Christopher |date=4 January 2010|work=The International Variable Star Index |publisher=American Association of Variable Star Observers|access-date=10 March 2015}}</ref>

[[TY Coronae Borealis]] is a [[pulsating white dwarf]] (of ZZ Ceti) type, which is around 70% as massive as the Sun, yet has only 1.1% of its diameter.<ref>{{cite journal|author1=Romero, A. D. |author2=Córsico, A. H. |author3=Althaus, L. G. |author4-link=Kepler de Souza Oliveira |author4=Kepler, S. O. |author5=Castanheira, B. G. |author6=Miller Bertolami, M. M. |date=2012|title=Toward ensemble asteroseismology of ZZ Ceti stars with fully evolutionary models|journal=Monthly Notices of the Royal Astronomical Society|volume=420|issue=2|pages=1462–80| doi=10.1111/j.1365-2966.2011.20134.x |doi-access=free |bibcode=2012MNRAS.420.1462R|arxiv = 1109.6682 |s2cid=55018129 }}</ref> Discovered in 1990, [[UW Coronae Borealis]] is a [[X-ray binary#Low-mass X-ray binary|low-mass X-ray binary]] system composed of a star less massive than the Sun and a neutron star surrounded by an [[accretion disk]] that draws material from the companion star. It varies in brightness in an unusually complex manner: the two stars orbit each other every 111 minutes, yet there is another cycle of 112.6 minutes, which corresponds to the orbit of the disk around the degenerate star. The beat period of 5.5 days indicates the time the accretion disk—which is asymmetrical—takes to [[Precession (mechanical)|precess]] around the star.<ref name="Mason 2012">{{cite journal|author1=Mason, Paul A. |author2=Robinson, Edward L. |author3=Bayless, Amanda J. |author4=Hakala, Pasi J. |date=2012|title=Long-term Optical Observations of Two LMXBS: UW CrB (=MS 1603+260) and V1408 Aql (=4U 1957+115)|journal=The Astronomical Journal|volume=144|issue=4|pages=108 |doi=10.1088/0004-6256/144/4/108 |bibcode=2012AJ....144..108M|hdl=2152/34339 |s2cid=122184568 |hdl-access=free }}</ref>

=== Extrasolar planetary systems ===
[[Extrasolar planets]] have been confirmed in five star systems, four of which were found by the [[methods of detecting exoplanets#Radial velocity|radial velocity]] method. The spectrum of [[Epsilon Coronae Borealis]] was analysed for seven years from 2005 to 2012, revealing a planet around 6.7&nbsp;times as massive as [[Jupiter]] ({{Jupiter mass|link=y}}) orbiting every 418&nbsp;days at an average distance of around 1.3&nbsp;AU.<ref name="lee 2012">{{cite journal|author1=Lee, B.-C. |author2=Han, I. |author3=Park, M.-G. |author4=Mkrtichian, D. E. |author5=Kim, K.-M. |date=2012|title=A planetary companion around the K giant ɛ Corona Borealis|journal=Astronomy & Astrophysics|volume=546|id=A5|pages=5|bibcode=2012A&A...546A...5L|doi=10.1051/0004-6361/201219347|arxiv = 1209.1187 |s2cid=55260442 }}</ref> Epsilon itself is a {{Solar mass|1.7}} orange giant of spectral type K2III that has swollen to {{Solar radius|21}} and {{Solar luminosity|151}}.<ref name=aj135_1_209>{{cite journal | last1=Massarotti | first1=Alessandro | last2=Latham | first2=David W. | last3=Stefanik | first3=Robert P. | last4=Fogel | first4=Jeffrey | s2cid=121883397 | title=Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity | journal=The Astronomical Journal | volume=135 | issue=1 | pages=209–31 |date=January 2008 | doi=10.1088/0004-6256/135/1/209 | bibcode=2008AJ....135..209M | doi-access=free }}</ref> [[Kappa Coronae Borealis]] is a spectral type K1IV orange subgiant nearly twice as massive as the Sun; around it lies a dust debris disk,<ref name="Pawellek 2014"/> and one planet with a period of 3.4&nbsp;years.<ref name="PASJ">{{cite journal |journal=Publications of the Astronomical Society of Japan | volume = 64 |issue = 6 |id=135 |pages= 14 |title=Substellar Companions to Seven Evolved Intermediate-Mass Stars |arxiv=1207.3141 |year=2012 |author1=Sato, Bun'ei |author2=Omiya, Masashi |author3=Harakawa, Hiroki |author4=Izumiura, Hideyuki |author5=Kambe, Eiji |author6=Takeda, Yoichi |author7=Yoshida, Michitoshi |author8=Itoh, Yoichi |author9=Ando, Hiroyasu |author10=Kokubo, Eiichiro |author11=Ida, Shigeru |bibcode = 2012PASJ...64..135S |doi = 10.1093/pasj/64.6.135| s2cid = 119197073 }}</ref> This planet's mass is estimated at {{Jupiter mass|2.5|link=y}}. The dimensions of the debris disk indicate it is likely there is a second substellar companion.<ref name=Bonsor13>{{cite journal |author1=Bonsor, Amy |author2=Kennedy, Grant M. |author3=Crepp, Justin R. |author4=Johnson, John A. |author5=Wyatt, Mark C. |author6=Sibthorpe, Bruce |author7=Su, Kate Y. L. |year=2013 |title=Spatially Resolved Images of Dust Belt(s) Around the Planet-hosting Subgiant κ CrB |journal=[[Monthly Notices of the Royal Astronomical Society|MNRAS]] |volume=431 |issue= 4|pages=3025–3035 |doi=10.1093/mnras/stt367 |doi-access=free |arxiv = 1302.7000 |bibcode = 2013MNRAS.431.3025B |s2cid=27703182 }}</ref> [[Omicron Coronae Borealis]] is a K-type [[Red clump|clump giant]] with one confirmed planet with a mass of {{Jupiter mass|0.83}} that orbits every 187&nbsp;days—one of the two least massive planets known around clump giants.<ref name="PASJ"/> [[HD 145457]] is an orange giant of spectral type K0III found to have one planet of {{Jupiter mass|2.9}}. Discovered by the Doppler method in 2010, it takes 176&nbsp;days to complete an orbit.<ref name="sato 2010">{{cite journal|author1=Sato, Bun'ei |author2=Omiya, Masashi |author3=Liu, Yujuan |author4=Harakawa, Hiroki |author5=Izumiura, Hideyuki |author6=Kambe, Eiji |author7=Toyota, Eri |author8=Murata, Daisuke |author9=Lee, Byeong-Cheol |author10=Masuda, Seiji |author11=Takeda, Yoichi |author12=Yoshida, Michitoshi |author13=Itoh, Yoichi |author14=Ando, Hiroyasu |author15=Kokubo, Eiichiro |author16=Ida, Shigeru |author17=Zhao, Gang |author18=Han, Inwoo |date=2010|title=Substellar Companions to Evolved Intermediate-Mass Stars: HD 145457 and HD 180314|journal=Publications of the Astronomical Society of Japan|volume=62|issue=4|pages=1063–69|bibcode=2010PASJ...62.1063S|doi=10.1093/pasj/62.4.1063|arxiv = 1005.2860 |s2cid=119113950 }}</ref> [[XO-1]] is a magnitude 11 [[G-type main-sequence star|yellow main-sequence star]] located approximately {{convert|172|pc|ly|disp=output number only}} light-years away,<ref name="Torres2008">{{cite journal | title=Improved Parameters for Extrasolar Transiting Planets | last1=Torres | first1=Guillermo | last2=Winn | first2=Joshua N. | last3=Holman | first3=Matthew J. | journal=The Astrophysical Journal | volume=677 | issue=2 | pages=1324–42 | year=2008 | arxiv=0801.1841 | bibcode=2008ApJ...677.1324T | doi=10.1086/529429 | s2cid=12899134 }}</ref> of spectral type G1V with a mass and radius similar to the Sun. In 2006 the [[hot Jupiter]] exoplanet [[XO-1b]] was discovered orbiting XO-1 by the [[Methods of detecting exoplanets#Transit photometry|transit method]] using the [[XO Telescope]]. Roughly the size of Jupiter, it completes an orbit around its star every three days.<ref name="McCullough2006">{{cite journal | title=A Transiting Planet of a Sun-like Star | last1=McCullough | first1=P. R. | last2=Stys | first2=J. E. | last3=Valenti | first3=Jeff A. | last4=Johns-krull | first4=C. M. | last5=Janes | first5=K.A. | last6=Heasley | first6=J. N. | last7=Bye | first7=B. A. | last8=Dodd | first8=C. | last9=Fleming | first9=S. W. | last10=Pinnick | first10=A. | last11=Bissinger | first11=R. | last12=Gary | first12=B. L. | last13=Howell | first13=P. J. | last14=Vanmunster | first14=T. | journal=The Astrophysical Journal | volume=648 | issue=2 | pages=1228–38 | year=2006 | arxiv=astro-ph/0605414 | bibcode=2006ApJ...648.1228M | doi=10.1086/505651| s2cid=8100425 }}</ref><!-- cites previous 1.5 sentences -->

The discovery of a Jupiter-sized planetary companion was announced in 1997 via analysis of the radial velocity of Rho Coronae Borealis, a yellow main sequence star and [[Solar analog]] of spectral type G0V,<ref name="Belle">{{cite journal | author=van Belle, Gerard T.  | author2=von Braun, Kaspar  | title=Directly Determined Linear Radii and Effective Temperatures of Exoplanet Host Stars | journal=[[The Astrophysical Journal]] | volume=694 | issue=2 | date=2009 | pages=1085–98| doi=10.1088/0004-637X/694/2/1085 | bibcode=2009ApJ...694.1085V|arxiv = 0901.1206 | s2cid=18370219 }}</ref> around 57 light-years distant from Earth.<ref>{{cite journal|author1=Noyes, Robert W. |author2=Jha, Saurabh |author3=Korzennik, Sylvain G. |author4=Krockenberger, Martin |author5=Nisenson, Peter |author6=Brown, Timothy M. |author7=Kennelly, Edward J. |author8=Horner, Scott D. |title=A Planet Orbiting the Star ρ Coronae Borealis|year=1997|journal=The Astrophysical Journal|volume=483|issue=2|pages=L111–14|doi=10.1086/310754|bibcode=1997ApJ...483L.111N|arxiv = astro-ph/9704248 |s2cid=115606006 }}</ref> More accurate measurement of data from the [[Hipparcos]] satellite subsequently showed it instead to be a low-mass star somewhere between 100 and 200 times the mass of Jupiter.<ref name="ReffertQuirrenbach">{{cite journal|author1=Reffert, S. |author2=Quirrenbach, A. |title=Mass constraints on substellar companion candidates from the re-reduced Hipparcos intermediate astrometric data: nine confirmed planets and two confirmed brown dwarfs|year=2011|journal=Astronomy & Astrophysics|volume=527|pages=A140|doi=10.1051/0004-6361/201015861|bibcode=2011A&A...527A.140R|arxiv=1101.2227|s2cid=54986291 }}</ref> Possible stable planetary orbits in the [[Circumstellar habitable zone|habitable zone]] were calculated for the binary star [[Eta Coronae Borealis]],<ref>{{cite journal|last=Benest|first=D.|date=1996|title= Planetary orbits in the elliptic restricted problem. III. The η Coronae Borealis system.|journal=Astronomy and Astrophysics|volume=314|pages=983–88|bibcode=1996A&A...314..983B}}</ref> which is composed of two stars—yellow main sequence stars of spectral type G1V and G3V respectively—similar in mass and spectrum to the Sun.<ref name=kalereta>{{cite web| first1=James B. | last1=Kaler | title=Eta Coronae Borealis | work=Stars | publisher=University of Illinois | url=http://stars.astro.illinois.edu/sow/etacrb.html | date =22 June 2012 | access-date=16 March 2015}}</ref> No planet has been found, but a brown dwarf companion about 63 times as massive as Jupiter with a spectral type of L8 was discovered at a distance of 3640&nbsp;AU from the pair in 2001.<ref name="brown">{{cite journal | title=Brown Dwarf Companions to G-Type Stars. I. Gliese 417B and Gliese 584C | journal=The Astronomical Journal | volume=121 | issue=6 | pages=3235–3253 |author1=Kirkpatrick, J. Davy |author2=Dahn, Conard C. |author3=Monet, David G. |author4=Reid, I. Neill |author5=Gizis, John E. |author6=Liebert, James |author7=Burgasser, Adam J. | year=2001 | arxiv=astro-ph/0103218 |bibcode=2001AJ....121.3235K |doi = 10.1086/321085 | s2cid=18515414 }}</ref>

=== Deep-sky objects ===
[[File:Abell2142 chandra xray.jpg|thumb|left|upright|X-ray image of galaxy cluster [[Abell 2142]]]]
Corona Borealis contains few galaxies observable with amateur telescopes.<ref>{{cite book|last=Luginbuhl|first=Christian B. |author2=Skiff, Brian A. |title=Observing Handbook and Catalogue of Deep-Sky Objects|publisher=Cambridge University Press|location=Cambridge, United Kingdom|date=1998|pages=92|isbn=978-0-521-62556-2|url=https://books.google.com/books?id=MwCyjQpGU7UC&pg=PA92}}</ref> [[NGC 6085]] and [[NGC 6086|6086]] are a faint [[spiral galaxy|spiral]] and [[elliptical galaxy]] respectively close enough to each other to be seen in the same visual field through a telescope.<ref name="Rumistrzewicz">{{cite book|last=Rumistrzewicz|first=Stefan |title=A Visual Astronomer's Photographic Guide to the Deep Sky: A Pocket Field Guide|publisher=Springer Science & Business Media|location=New York, New York|date=2010|pages=158|isbn=978-1-4419-7242-2|url=https://books.google.com/books?id=Vhjn3DEJpyIC&pg=PA158}}</ref> [[Abell 2142]] is a huge (six million light-year diameter), [[X-ray]] luminous [[galaxy cluster]] that is the result of an ongoing merger between two galaxy clusters. It has a [[redshift]] of 0.0909 (meaning it is moving away from us at 27,250&nbsp;km/s) and a visual magnitude of 16.0. It is about 1.2 [[1,000,000,000 (number)|billion]] light-years away.{{efn|1=Distance calculated from redshift.}}<ref name="NED">{{cite web | title= NASA/IPAC Extragalactic Database  | work= Results for Abell 2142  | url= http://nedwww.ipac.caltech.edu/ | access-date = 11 Nov 2008 | archive-url= https://web.archive.org/web/20081216032441/http://nedwww.ipac.caltech.edu/| archive-date= 16 December 2008 | url-status= live}}</ref> Another galaxy cluster in the constellation, [[RX J1532.9+3021|RX&nbsp;J1532.9+3021]], is approximately 3.9 billion [[light-year]]s from Earth.<ref name="chandra">{{cite web | url =http://chandra.harvard.edu/photo/2014/rxj1532/| title =RX J1532.9+3021: Extreme Power of Black Hole Revealed |publisher =Chandra X-ray Center|date=January 23, 2014| access-date =27 January 2014 }}</ref> At the cluster's center is a large elliptical galaxy containing one of the [[List of most massive black holes|most massive]] and most powerful [[supermassive black hole]]s yet discovered.<ref name="chandra"/>  [[Abell 2065]] is a highly concentrated galaxy cluster containing more than 400 members, the brightest of which are 16th magnitude; the cluster is more than one billion light-years from Earth.{{sfn|Ridpath|Tirion|2001|pp=126–128}} On a larger scale still, Abell&nbsp;2065, along with [[Abell 2061]], [[Abell 2067]], [[Abell 2079]], [[Abell 2089]], and [[Abell 2092]], make up the [[Corona Borealis Supercluster]].<ref name=postman88>{{cite journal |title=The dynamics of the Corona Borealis supercluster |author1=Postman, M. |author2=Geller, M. J. |author3=Huchra, J. P. |journal=Astronomical Journal | volume= 95 |year= 1988 |pages= 267–83 |doi=10.1086/114635 |bibcode=1988AJ.....95..267P}}</ref> Another galaxy cluster, [[Abell 2162]], is a member of the [[Hercules Superclusters]].<ref name=kopylova>{{cite journal|author1=Kopylova, F. G. |author2=Kopylov, A. I. |date=2013|title=Investigation of properties of galaxy clusters in the Hercules supercluster region|journal=Astronomy Letters|volume=39|issue=1|pages=1–16|doi=10.1134/S1063773712120043 | bibcode= 2013AstL...39....1K |s2cid=120136802 }}</ref>{{Clear}}

== Mythology ==
[[File:Sidney Hall - Urania's Mirror - Hercules and Corona Borealis.jpg|thumb|[[Hercules (constellation)|Hercules]] and Corona Borealis, as depicted in ''[[Urania's Mirror]]'' ({{circa|1825}})]]
In [[Greek mythology]], Corona Borealis was linked to the legend of [[Theseus#The myth of Theseus and the Minotaur|Theseus and the minotaur]]. It was generally considered to represent a crown given by [[Dionysus]] to [[Ariadne]], the daughter of [[Minos]] of Crete, after she had been abandoned by the Athenian prince [[Theseus]]. When she wore the crown at her marriage to Dionysus, he placed it in the heavens to commemorate their wedding.{{sfn|Ridpath|Tirion|2001|pp=126–128}} An alternative version has the besotted Dionysus give the crown to Ariadne, who in turn gives it to Theseus after he arrives in Crete to kill the [[minotaur]] that the Cretans have demanded tribute from Athens to feed. The hero uses the crown's light to escape the labyrinth after disposing of the creature, and Dionysus later sets it in the heavens. {{lang|la|[[De astronomia]]}}, attributed to [[Gaius Julius Hyginus|Hyginus]], linked it to a crown or wreath worn by Bacchus (Dionysus) to disguise his appearance when first approaching [[Mount Olympus]] and revealing himself to the gods, having been previously hidden as yet another child of Jupiter's trysts with a mortal, in this case [[Semele]]. Its proximity to the constellations [[Hercules (constellation)|Hercules]] (which {{lang|la|De astronomia}} reports was once attributed to Theseus, among others) and [[Lyra (constellation)|Lyra]] (Theseus' lyre in one account) could indicate that the three constellations were invented as a group.<ref>{{cite book | translator-first=Robin | translator-last=Hard | chapter=Hercules, originally known as Engonasin, the Kneeler | title=Constellation Myths | year=2015 | isbn=9780191026539 | publisher=Oxford University Press }}</ref> Corona Borealis was one of the 48 constellations mentioned in the ''[[Almagest]]'' of classical astronomer [[Ptolemy]].<ref name=wagman/>

In [[Mesopotamian Mythology|Mesopotamia]], Corona Borealis was associated with the goddess [[Nanaya]].<ref>M. Stol, ''Nanaja'' [in:] ''[http://publikationen.badw.de/en/rla/index Reallexikon der Assyriologie und vorderasiatischen Archäologie]'' vol 9, 1998, p. 147</ref>

In [[Welsh mythology]], it was called [[Caer]] Arianrhod, "the Castle of the Silver Circle", and was the heavenly abode of the Lady [[Arianrhod]].<ref>{{cite book| last1 = Squire | first1 = Charles L. |pages=154–55  | year = 2000 | title = The Mythology of the British Islands | publisher = Wordsworth Editions Ltd  |location = Ware, United Kingdom | isbn = 978-1-84022-500-6}}</ref> To the ancient Balts, Corona Borealis was known as ''Darželis'', the "flower garden".<ref>{{cite journal | title=The Cosmology of the Ancient Balts |author1=Straižys, V. |author2=Klimka, L.  | journal=Journal for the History of Astronomy, Archaeoastronomy Supplement | volume= 28|issue=22 |page=S57 |bibcode=1997JHAS...28...57S | doi=10.1177/002182869702802207|year=1997 |s2cid=117470993 }}</ref>

The Arabs called the constellation Alphecca (a name later given to Alpha Coronae Borealis), which means "separated" or "broken up" ({{lang|ar|الفكة}} ''{{Transliteration|ar|al-Fakkah}}''), a reference to the resemblance of the stars of Corona Borealis to a loose string of jewels.<ref>{{cite book|author1=Kunitzch, Paul |author2=Smart, Tim | title=A Dictionary of Modern Star Names: A Short Guide to 254 Star Names and Their Derivations |page=30 |year=2006 | publisher=Sky Publishing Corporation |location=Cambridge, Massachusetts |isbn=978-1-931559-44-7 | orig-year=1986}}</ref> This was also interpreted as a broken dish.<ref name="Raymo">{{cite book|last=Raymo|first=Chet |title=Three Hundred and Sixty Five Starry Nights: An Introduction to Astronomy for Every Night of the Year|publisher=Simon and Schuster|location=New York, New York|date=1990|orig-year=1982|page=101|isbn=978-0-671-76606-1|url=https://books.google.com/books?id=rTe5HaRsAS4C&pg=PA101}}</ref> Among the [[Bedouins]], the constellation was known as ''{{Transliteration|ar|DIN|qaṣʿat al-masākīn}}''  ({{lang|ar|قصعة المساكين}}), or "the dish/bowl of the poor people".<ref>{{cite book|title=An Eleventh-Century Egyptian Guide to the Universe: The Book of Curiosities, Edited with an Annotated Translation|url=https://books.google.com/books?id=ERJMAgAAQBAJ&pg=PA622|author1=Rapoport, Yossef |author2=[[Savage-Smith, Emilie]] | publisher=BRILL|location= Leiden, Netherlands|isbn=978-90-04-25699-6|page=622|date=2013}}</ref>

The [[Skidi]] people of [[Native Americans in the United States|Native Americans]] saw the stars of Corona Borealis representing a council of stars whose chief was [[Polaris]].<ref name="hall">{{cite journal|last=Hall|first=Robert L.|date=2005|title=Contradictions as a Source of Historical Perspective: Camp Circles and Sacred Poles|journal=Ontario Archaeology|issue=79/80|pages=115–26 [122]|url=http://www.ontarioarchaeology.on.ca/publications/pdf/oa_79-80hall.pdf |archive-url=https://web.archive.org/web/20150227150425/http://www.ontarioarchaeology.on.ca/publications/pdf/oa_79-80hall.pdf |archive-date=2015-02-27 |url-status=live}}</ref> The constellation also symbolised the smokehole over a fireplace, which conveyed their messages to the gods, as well as how chiefs should come together to consider matters of importance.<ref>{{cite book|last=Chamberlain|first=Von Del|title=Archaeoastronomy in the New World: American Primitive Astronomy : Proceedings of an International Conference Held at Oxford University, September, 1981|editor=Anthony F. Aveni|publisher=Cambridge University Press|location=Cambridge, United Kingdom|date=1982|pages=184|chapter=Earth Lodge as Observatory|isbn=978-0-521-24731-3}}</ref> The [[Shawnee]] people saw the stars as the ''Heavenly Sisters'', who descended from the sky every night to dance on earth. Alphecca signifies the youngest and most comely sister, who was seized by a hunter who transformed into a field mouse to get close to her. They married though she later returned to the sky, with her heartbroken husband and son following later.<ref name="Raymo"/><!-- cites previous three sentences --> The [[Mi'kmaq]] of eastern Canada saw Corona Borealis as ''Mskegwǒm'', the den of the celestial bear (Alpha, Beta, Gamma and Delta Ursae Majoris).<ref>{{cite journal|last=Hagar|first=Stansbury |date=1900|title=The Celestial Bear|journal=The Journal of American Folklore|volume=13|issue=49|pages=92–103|jstor=533799|doi=10.2307/533799}}</ref>

[[Polynesian people]]s often recognized Corona Borealis; the people of the [[Tuamotus]] named it ''Na Kaua-ki-tokerau'' and probably ''Te Hetu''. The constellation was likely called ''Kaua-mea'' in [[Hawaii]], ''Rangawhenua'' in [[New Zealand]], and ''Te Wale-o-Awitu'' in the Cook Islands atoll of [[Pukapuka]]. Its name in [[Tonga]] was uncertain; it was either called ''Ao-o-Uvea'' or ''Kau-kupenga''.<ref>{{cite book| last = Makemson | first = Maud Worcester |page=282| year = 1941  | publisher = Yale University Press  |location  = New Haven, Connecticut  | title = The Morning Star Rises: an account of Polynesian astronomy| bibcode = 1941msra.book.....M }}</ref>

In [[Australian Aboriginal astronomy]], the constellation is called ''womera'' ("the [[boomerang]]") due to the shape of the stars.<ref>{{cite book| page= 151 |url=https://books.google.com/books?id=TIatz2DGXQwC |title=Star Lore: Myths, Legends, and Facts|author=Olcott, William Tyler |location= New York, New York |publisher = Dover Publication Inc.|isbn=978-0-486-43581-7|year= 2004}}</ref> The Wailwun people of northwestern New South Wales saw Corona Borealis as ''mullion wollai'' "eagle's nest", with [[Altair]] and [[Vega]]—each called ''mullion''—the pair of eagles accompanying it.<ref name="ridley1875">{{cite book|last=Ridley|first=William|title=Kámilarói, and other Australian languages|publisher=T. Richards, government printer|location=Sydney, New South Wales|year=1875|edition=2nd|pages=141–42}}</ref> The [[Wardaman people]] of northern Australia held the constellation to be a gathering point for Men's Law, Women's Law and Law of both sexes come together and consider matters of existence.<ref>{{cite book  | last1 = Harney  | first1 = Bill Yidumduma   | last2 = Cairns  | first2 = Hugh C.  | title = Dark Sparklers  | publisher = Hugh C. Cairns  | location = Merimbula, New South Wales |pages=98, 105  | year = 2004  | orig-year = 2003  | edition = Revised  | isbn = 0-9750908-0-1}}</ref>

=== Later references ===
Corona Borealis was renamed Corona Firmiana in honour of the Archbishop of Salzburg in the 1730 Atlas ''Mercurii Philosophicii Firmamentum Firminianum Descriptionem'' by Corbinianus Thomas, but this was not taken up by subsequent cartographers.<ref>{{cite book | first=Nick | last=Kanas | date=2007 | title=Star maps: history, artistry, and cartography | pages=207–09 |url=https://books.google.com/books?id=bae3LP4tfP4C&pg=PA208 | publisher=Springer |location=New York, New York | isbn=978-0-387-71668-8 }}</ref> The constellation was featured as a main plot ingredient in the short story "[[Hypnos (short story)|Hypnos]]" by [[H. P. Lovecraft]], published in 1923; it is the object of fear of one of the protagonists in the short story.<ref>{{cite book|last=Smith|first=Don G. |title=H.P. Lovecraft in Popular Culture: The Works and Their Adaptations in Film, Television, Comics, Music and Games|publisher=McFarland|location=Jefferson, North Carolina|date=2005|pages=16|isbn=0-7864-2091-X|url=https://books.google.com/books?id=3jTFK9HTZaUC&pg=PA16}}</ref> Finnish band [[Cadacross]] released an album titled ''[[Corona Borealis (album)|Corona Borealis]]'' in 2002.<ref>{{cite web|url=http://www.allmusic.com/album/corona-borealis-mw0000335058|title=Cadacross Corona Borealis|work=Allmusic|date=2015|publisher=All Media Network|access-date=14 March 2015}}</ref>

== See also ==
* [[Corona Borealis (Chinese astronomy)]]

== Notes ==
{{notelist}}

== References ==
<references>

<ref name=Kirkpatrick2024>{{cite journal |last1=Kirkpatrick |first1=J. Davy |last2=Marocco |first2=Federico |display-authors=etal |date=April 2024 |title=The Initial Mass Function Based on the Full-sky 20 pc Census of ~3600 Stars and Brown Dwarfs |journal=[[The Astrophysical Journal Supplement Series]] |volume=271 |issue=2 |pages=55 |doi=10.3847/1538-4365/ad24e2 |doi-access=free |arxiv=2312.03639 |bibcode=2024ApJS..271...55K}}</ref>

</references>

=== Cited texts ===
* {{cite book  | last1 = Ridpath  | first1 = Ian  | last2 = Tirion  | first2 = Wil  | year = 2001  | title = Stars and Planets Guide  | publisher = Princeton University Press  |location  = Princeton, New Jersey  | isbn = 978-0-691-08913-3 }}

==External links==
* {{Commons-inline}}
* [https://iconographic.warburg.sas.ac.uk/category/vpc-taxonomy-017043 Warburg Institute Iconographic Database (ca 160 medieval and early modern images of Corona Borealis)]

{{Stars of Corona Borealis}}
{{Constellations}}
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[[Category:Corona Borealis| ]]
[[Category:Ariadne]]
[[Category:Constellations listed by Ptolemy]]
[[Category:Constellations]]
[[Category:Mythological clothing]]
[[Category:Mythology of Dionysus]]
[[Category:Northern constellations]]
[[Category:Objects in Greek mythology]]