View source for V Coronae Borealis

{{Short description|Mira-type long period variable star in the constellation Corona Borealis}}
{{Starbox begin}}
{{Starbox image
| image = [[Image:V Coronae Borealis.jpg|250px]]
| caption = V Coronae Borealis in optical light
}}
{{Starbox observe|
|constell= [[Corona Borealis]]
|epoch=J2000
|name= V Coronae Borealis
|ra=   {{RA|15|49|31.31093}}<ref name="SIMBAD">{{cite web |url =http://simbad.u-strasbg.fr/simbad/sim-id?Ident=V+CrB&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id|title = V Coronae Borealis|work = SIMBAD Astronomical Database|publisher=Centre de Données astronomiques de Strasbourg|access-date = 13 November 2014}}</ref>
|dec=  {{DEC|+39|34|17.9111}}<ref name=SIMBAD/>
| appmag_v = 6.90<ref name=SIMBAD/>
}}
{{Starbox character|
|class= C6,2e(N2e)<ref name="AAVSO"/>}}
{{Starbox astrometry
|dist_pc=630
|dist_footnote=<ref name=Danilovich2015/>
}}
{{Starbox detail
|source=<ref name=Danilovich2015/>
|radius={{solar radius calculator|type=LT|5300|1800|decimals=-1}}{{efn|name=radius}}
|luminosity=5300
|temperature=1800
}}
{{Starbox reference|
| names = [[Durchmusterung|BD]]+40°&nbsp;2929, [[Henry Draper Catalogue|HD]]&nbsp;141826, [[Hipparcos catalogue|HIP]]&nbsp;77501, [[SAO Catalogue|SAO]]&nbsp;64929
| Simbad = V+CrB
}}
{{Starbox end}}
[[File:VCrBLightCurve.png|thumb|right|The [[Photometric_system#Photometric_letters|visual band]] [[light curve]] of V Coronae Borealis, from AAVSO data<ref name="aavso"/>]]

'''V Coronae Borealis''' ('''V CrB''') is a [[Mira variable|Mira-type]] long period [[variable star]] and [[carbon star]] in the [[constellation]] [[Corona Borealis]]. Its [[apparent magnitude]] varies between 6.9 and 12.6 over a period of 357 days.<ref name="AAVSO">{{cite web|url=http://www.aavso.org/vsx/index.php?view=detail.top&oid=10604 |title=V Coronae Borealis|author=VSX|date=4 January 2010|work=AAVSO Website|publisher=[[American Association of Variable Star Observers]]|access-date=13 November 2014}}</ref>

V Coronae Borealis is too far from Earth for its parallax to be measured effectively. Basing on a period of 357 days,   the [[absolute magnitude]] of V Coronae Borealis has been calculated to be -4.62.<ref>{{cite journal | bibcode=2013A&A...555A.120G    |title=Luminosities of carbon-rich asymptotic giant branch stars in the Milky Way |author = Guandalini, R. |author2 = Cristallo, S. |journal = Astronomy & Astrophysics |volume = 555 | id = A120 | pages = 7 |date=2013|arxiv = 1305.4203 |doi = 10.1051/0004-6361/201321225 |s2cid=54918450 }}</ref> It is estimated to be {{cvt|630|pc|ly|lk=on|abbr=off}} from Earth, has a luminosity of {{solar luminosity|5,300|link=y}} and a rather cool effective temperature of 1,800&nbsp;[[Kelvin|K]], these implying a very large radius of about {{solar radius calculator|type=LT|5300|1800|decimals=-1|unit=y|link=y}}, making V Coronae Borealis [[List of largest known stars|one of the largest stars]] so far discovered.<ref name=Danilovich2015/> If placed in the center of the Solar System, its size would engulf all [[rocky planet]]s and reach parts of the [[asteroid belt]].

==Notes==
{{Notelist|notes=

{{efn | name=radius | Applying the [[Stefan–Boltzmann law]] with a nominal [[sun|solar]] [[effective temperature]] of {{val|5772|ul=K|fmt=commas}}: 
:<math>\sqrt{(5772/1800)^4 * 5,300} = 750\ R\odot</math>}}

}}

==References==
{{reflist|refs=

<ref name="aavso">{{cite web |title=Download Data |url=https://www.aavso.org/data-download |website=aavso.org |publisher=AAVSO |access-date=1 October 2021}}</ref>

<ref name=Danilovich2015>{{Cite journal |last=Danilovich |first=T. |last2=Teyssier |first2=D. |last3=Justtanont |first3=K. |last4=Olofsson |first4=H. |last5=Cerrigone |first5=L. |last6=Bujarrabal |first6=V. |last7=Alcolea |first7=J. |last8=Cernicharo |first8=J. |last9=Castro-Carrizo |first9=A. |last10=García-Lario |first10=P. |last11=Marston |first11=A. |date=2015-09-01 |title=New observations and models of circumstellar CO line emission of AGB stars in the Herschel SUCCESS programme |bibcode=2015A&A...581A..60D |journal=Astronomy and Astrophysics |volume=581 |pages=A60 |doi=10.1051/0004-6361/201526705 |issn=0004-6361|arxiv=1506.09065 }}</ref>

}}

{{Stars of Corona Borealis}}

{{DEFAULTSORT:V Coronae Borealis}}
[[Category:Corona Borealis]]
[[Category:Mira variables]]
[[Category:Objects with variable star designations|Coronae Borealis, V]]
[[Category:Carbon stars]]
[[Category:Durchmusterung objects]]
[[Category:Henry Draper Catalogue objects|141826]]
[[Category:Hipparcos objects|077501]]


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