View source for VY Canis Majoris

{{Use dmy dates|date=September 2012}}
{{Starbox begin}}
{{Starbox image
| image    = [[File:VY Canis Majoris.jpg|277px]]
| caption  = Satellite image showing the giant mass ejections from VY Canis Majoris.
| credit =
}}
{{Starbox observe
| epoch    = [[J2000.0]]
| equinox  = [[J2000.0]]
| ra       = {{RA|07|22|58.32877}}<ref name=hipparcos/>
| dec      = {{DEC|-25|46|03.2355}}<ref name=hipparcos/>
| appmag_v = 6.5 - 9.6<ref name=GCVS-VY-CMa/>
| constell = [[Canis Major]] 
| pronounce =
}}
{{Starbox character
| type = [[Red Hypergiant]]
| class = M3–M4.5<ref name="Wittkowski_vlti"/> {{nowrap|(M2.5<ref name=massey2006/> – M5e la<ref name="LipscyJura2005"/>)}}
| r-i = <!--R-I color-->
| v-r = +2.20<ref name=chicago1969/>
| b-v = +2.057<ref name=hipparcos/>
| u-b = +2.32<ref name=chicago1969/>
| j-h = <!--J-H color-->
| j-k = <!--J-K color-->
| appmag_1_passband = U
| appmag_1 = 12.01<ref name=flux/>
| appmag_2_passband = B
| appmag_2 = 10.19<ref name=flux/>
| appmag_3_passband = V
| appmag_3 = 7.95<ref name=flux/>
| appmag_4_passband = J
| appmag_4 = 1.98<ref name=flux/>
| appmag_5_passband = H
| appmag_5 = 0.44<ref name=flux/>
| appmag_6_passband = K
| appmag_6 = 8.1<ref name=debeck/>
| variable = [[Semiregular variable|SRc]]<ref name="GCVS-VY-CMa"/> or [[slow irregular variable|Lc]]<ref name=AAVSO-VY-CMa/>
}}
{{Starbox astrometry
| radial_v = 41<ref name=ejecta/>
| prop_mo_ra = 9.84<ref name=hipparcos/>
| prop_mo_dec = 0.75<ref name=hipparcos/>
| parallax = 0.83
| p_error  = 0.08
| parallax_footnote = <ref name=zhang/>
| dist_ly  = ~{{val|3,820|260|230|fmt=commas}}
| dist_pc  = {{val|1,170|80|70|fmt=commas}}<ref name="Wittkowski_vlti"/>
| absmag_v = &minus;9.4<ref name=molecules/>
}}
{{Starbox detail
| mass                   = {{val|17|8}}<ref name="Wittkowski_vlti"/>
| radius                 = 1,420 - 2,000<ref>https://doi.org/10.1051%2F0004-6361%2F201220290</ref>
| luminosity             = {{val|270,000|40,000|fmt=commas}}<ref name="Wittkowski_vlti"/>
| temperature            = {{val|3,490|90|fmt=commas}}<ref name="Wittkowski_vlti"/>
| metal_fe               = –0.3<ref name=mikako/>
| rotational_velocity    = 300<ref name=zhang/>
| gravity                = −{{val|0.6|0.4}}<ref name="Wittkowski_vlti"/>
| age_myr                = 8.2<ref name=zhang/>
}}
{{Starbox catalog
| names    = [[Variable star designation|VY]]&nbsp;CMa, [[Henry Draper Catalogue|HD]]&nbsp;58061, [[Hipparcos Catalogue|HIP]]&nbsp;35793, [[Durchmusterung|CD]]-25&nbsp;4441, [[AAVSO]]&nbsp;0718-25, [[IRAS]]&nbsp;07209-2540, [[Two-Micron Sky Survey|IRC]]&nbsp;&minus;30087, [[RAFGL]]&nbsp;1111, [[Smithsonian Astrophysical Observatory Star Catalog|SAO]]&nbsp;173571, [[Washington Double Star Catalog|WDS]]&nbsp;J07230-2546AB, [[2MASS]]&nbsp;J07225830-2546030
}}
{{Starbox reference
| Simbad = VY+CMa
}}
{{Starbox end}}'''VY Canis Majoris''' is an extreme red hypergiant of [[Stellar Classification|spectral class]] of M2.5-5Iae located in the constellation [[:Category:Stars of Canis Major|Canis Major]], it lies approximately 3,840 light years away from [[Earth]], and is also the [[List of largest stars|one of the largest known stars]]<ref name=Alcolea/> by size.

VY CMa is a non-binary star with a large [[infrared excess|infrared (IR) excess]], making it one of the brightest objects in the night sky at wavelengths measuring between 5 - 20 [[micron]]s (µm) and indicating a dust shell or disk heated by the star.<ref name=Nathan2001/><ref name=herbig/> The star's mass is estimated to be {{solar mass|17}}. Additionally, it is surrounded by a complex asymmetric [[circumstellar envelope]] (CSE) caused by [[Stellar mass loss|mass loss]] from the star itself. It produces strong molecular [[maser]] emission and was one of the first radio masers discovered.  VY CMa is embedded within the large [[molecular cloud]] [[Sharpless 310]] (Sh2-310), one of the largest star-forming regions with a diameter of 480 [[arcminutes]] (') or {{convert|681|ly|pc|abbr=on}}.<ref name=Sh2-310/><ref name=sharpless/>

The diameter of VY CMa is around 1,420–2,000 times that of the [[Sun]] ({{solar radius|link=y}}), which is close to the [[Hayashi limit]] and corresponds to a volume around 3 to 10 billion times greater than the [[Sun]]'s. A hypothetical object travelling at the [[speed of light]] would take anywhere between 6 to 8 hours to travel around the star's circumference, compared to only 14.5 seconds for the Sun.<ref name="SSE" /> If placed at the center of the [[Solar System]], VY CMa's [[photosphere]] would extend beyond the orbit of [[Saturn]], although there is still considerable variation in estimates of the radius, with some making it larger than only the orbit of [[Jupiter]].<ref name=massey2006/>

==Observational history==
[[File:Jérôme Lalande.jpg|thumb|left|upright=1|Portrait in bust of [[Jérôme Lalande]] in 1802]]
The discovery of VY Canis Majoris was done so by {{flags|fr}} French astronomer [[Jérôme Lalande]], on 7 March 1801, who listed it as a [[Apparent magnitude|7th magnitude]] star. Further 19th- and 20th-century studies of its [[apparent magnitude]] suggested that the star's magnitude has been fading since 1850.<ref name="Robinson"/> 

Since 1847, VY Canis Majoris has been described as a crimson star.<ref name="Robinson" /> During the 19th century, observers measured at least six discrete components, suggesting that it might be a [[Star system|binary star]]. These discrete components, however, are now known to be bright areas in the surrounding [[nebula]]. Visual observations made in 1957 and [[high resolution|high-resolution imaging]] in 1998 showed that VY Canis Majoris has no companion stars.<ref name="Robinson" /><ref name="Wittkowski"/> VY CMa was also discovered to be a strong source of [[Hydroxyl radical|OH]] (1612&nbsp;MHz), {{chem|link=water|H|2|O}} (22235.08&nbsp;MHz), and {{chem|link=Silicon monoxide|Si|O}} (43122&nbsp;MHz) [[astrophysical maser|masers]] emission, which is typical of an [[OH/IR star]].<ref name=wilson/><ref name=bartlett1969/><ref name=wilson1975/>  Many molecules, such as {{chem|link=Hydrogen cyanide|H|C|N}}, {{chem|link=Sodium chloride|Na|Cl}}, {{chem|link=Phosphorus mononitride|P|N}}, {{chem|link=Methylidyne radical|CH}}, {{chem|link=Carbon monoxide|CO}}, {{chem|link=Methanol|C|H|3|O|H}}, {{chem|link=Titanium oxide|TiO}}, and {{chem|link=Titanium dioxide|TiO|2}}, have also been detected.<ref name=molecules/><ref name=aavso/><ref name=Wittkowski_vlti/><ref name=debeck2015/><ref name=kaminski/>

The variation in VY CMa's brightness was first recorded down in 1931 when it was listed, in {{flags|de}} German, as a [[long period variable]] star with a [[photographic magnitude]] range of 9.5 to 11.5.<ref name=hoffmeister/> It was given the [[variable star designation]] '''VY Canis Majoris''' in 1939, meaning the 43th variable star of the constellation Canis Major.<ref name=guthnick/>

==Spectrum==
The spectrum of VY Canis Majoris is that of a high luminosity [[Stellar classification|M type star]]. The hydrogen lines, however, have [[P Cygni profile]]s fit for [[Luminous Blue Variables]]. The spectrum is dominated by TiO bands whose strengths suggest an exact class of M5. The [[H-alpha]] (H<sub>α</sub>) line is not visible yet and there are unusual [[emission line]]s of neutral elements such as [[sodium]] and [[calcium]]. The luminosity class as determined from different spectral features varies from [[bright giant]] (II) to bright supergiant (Ia), with a reasonable estimate being given as M5eIbp. Early attempts at classifying the star were confused by the interpretation of surrounding nebulosity as companion stars.<ref name=wallerstein/>

The derived spectral class varies depending on the features examined. The spectral features also vary noticeably over time. It is considered to be unambiguously cooler, and thus redder, than M2, and is usually classified anywhere from M3 to M5. Classes as hot or cool as M2.5 and M5 have also been given.<ref name=massey2006/> The luminosity class is likewise confused and often given only as I, partly because luminosity classes are poorly defined in the red and infrared portions of the spectrum. One study though, gives a luminosity class of Ia<sup>+</sup> which means a hypergiant or extremely luminous supergiant.<ref name=skiff/>

==Size==
[[File:Sun_and_VY_Canis_Majoris.svg|thumb|277px|left|VY Canis Majoris compared to the [[Sun]] and [[Earth]]'s orbit.]]
The calculation of the radius and diameter of {{PAGENAME}} is complicated by the extensive circumstellar envelope of the star. Since VY Canis Majoris is a pulsating star, its size changes over time. Earlier direct measurements of the radius at infrared ([[K band (infrared)|K-band]] = 2.2 µm) wavelengths gave an angular diameter approximately of {{val|18.7|0.5|u=mas}}, corresponding to a diameter above {{solar radius|3,000}} at an assumed distance of 1.5 kiloparsecs, considerably larger than expected for any red supergiant or hypergiant.<ref name=monnier/> However, this is probably larger than the actual size of the underlying star and the angular diameter estimate appears exceedingly large due to interference by the circumstellar envelope.<ref name=humphreys/><ref name=ejecta/><ref name=Wittkowski_vlti/> In 2006 to 2007, diameter estimates of {{convert|1,800 and 2,100|solar radius|km au mi|abbr=on}} have been derived from the estimated luminosity of {{solar luminosity|430,000}} and temperatures between 3,200 to 3,535 K.<ref name="humphreys" /><ref name="ejecta"/>. However, another diameter estimate of {{solar radius|1,420}} at a distance of approximately {{val|1.17|0.08|0.07|u=kpc}} was given. The high spectral resolution of these observations allowed to minimize the effects of interference by the circumstellar layers. An effective temperature of {{val|3,490|90|u=K|fmt=commas}} was then worked out from the radius and a luminosity around {{val|270,000|40,000|u={{solar luminosity}}|fmt=commas}}, which is based on distance and measured flux of {{val|6.3|0.3|e=-13|u=W/cm<sup>2</sup>}}, resulting to a spectral class of M4.<ref name="Wittkowski_vlti"/> In 2013, Alcolea et al. referred to VY Canis Majoris as the largest star ever found, which is considered the highest radius among well-characterized stars. Several other red supergiants or hypergiants (such as [[MY Cephei]] and [[NML Cygni]]) are possibly larger, but they have less accurate radius estimates.<ref name=Alcolea/>{{efn|name=radius}} During its main sequence, it was an [[Spectral Classification|O-type star]], having an initial mass of 25 times that of the sun, and a diameter of {{solar radius|5 to 20}}.

Most radius estimates of the VY CMa are considered as the size for the optical [[photosphere]] while the size of the star for the radio photosphere is calculated to be twice that of the size of the star for the optical photosphere.<ref name="LipscyJura2005"/>

Despite the star's mass and very large size, VY CMa has a very small average density of 5.33 to 8.38&nbsp;[[milligram|milligrams]]/[[Cubic meter|m<sup>3</sup>]] (0.00000533 to 0.00000838&nbsp;[[kilogram]]s per [[Cubic meter|m<sup>3</sup>]]); it is more than 100,000 times less dense than Earth's [[atmosphere]] at [[sea level]] (which is 1.2 kg/m<sup>3</sup>).

==Hypernova==
VY CMa is a very unstable star who has thrown off much of its mass into its surrounding nebula. In approximately 100,000 years, it will likely have exploded in a powerful [[hypernova]] (Superluminous supernova), with a luminosity more than 100 times brighter than that of a standard [[supernova]] but before, it will first shrink, becoming a [[yellow hypergiant]], then a [[Luminous Blue Variables|luminous blue variable]], and finally a Wolf-Rayet star. After exploding into a [[hypernova]], it will definitely end up in a black hole.

== Gallery ==
<gallery>
File:VYNMLIRC.png|VY Canis Majoris's circumstellar nebula compared to that of the [[yellow hypergiant]] [[IRC +10420]], and that of another famous red hypergiant [[NML Cygni]]. {{Credits|NASA, ESA, and R. Humphreys from the university of Minnesota.}}
File:Star-sizes.jpg|VY Canis Majoris compared to several other stars. {{Credit|Dave Jarvis on Wikimedia Commons}}
File:Rho Cassiopeiae Sol VY Canis Majoris.png|VY Canis Majoris compared to [[Betelgeuse]], [[Rho Cassiopeiae]], and the [[Pistol Star]].
File:VY Canis Hypergiant.jpg|Artist's impression of VY Canis Majoris.
File:Terameter group.png|VY Canis Majoris, [[Eta Carinae]], the [[Pale Blue Dot]] image, [[VV Cephei A]], and the Kuiper Belt.
</gallery>

== See also ==
* [[R136a1]], the most massive star known
* [[CT Cha b]], one of largest known exoplanets

{| class="article-table"
! colspan="2" |<< [[Westerlund 1-26]] (possibly)
!1. VY Canis Majoris
!2. [[VV Cephei A]] >>
|}

== References ==
* http://iopscience.iop.org/article/10.1086/306761/meta
* http://adsabs.harvard.edu/abs/1971IBVS..599....1R
{{reflist|refs=

<ref name=massey2006>{{cite journal | last1 = Massey | first1 = Philip | last2 = Levesque | first2 = Emily M. | last3 = Plez | first3 = Bertrand | title = Bringing VY Canis Majoris down to size: an improved determination of its effective temperature | journal = The Astrophysical Journal | volume = 646 | issue = 2 | pages = 1203–1208 | date = 1 August 2006 |arxiv=astro-ph/0604253 | doi = 10.1086/505025 | bibcode=2006ApJ...646.1203M| year = 2006 }}</ref>

<ref name="humphreys">{{cite journal|bibcode=2006astro.ph.10433H|arxiv=astro-ph/0610433|title=VY Canis Majoris: The Astrophysical Basis of Its Luminosity|pages=astro–ph/0610433|author1=Humphreys|first1=Roberta M.|year=2006}}</ref>

<ref name="Wittkowski_vlti">{{cite journal | doi = 10.1051/0004-6361/201219126 | last1 = Wittkowski | first1 = M. | last2 = Hauschildt | first2 = P.H. | last3 = Arroyo-Torres | first3 = B. | last4 = Marcaide | first4 = J.M. | title = Fundamental properties and atmospheric structure of the red supergiant VY CMa based on VLTI/AMBER spectro-interferometry | journal = Astronomy & Astrophysics | volume = 540 | pages = L12 | date = 5 April 2012 | bibcode=2012A&A...540L..12W|arxiv=1203.5194}}</ref>

<ref name="Choi">{{cite journal |title=Distance to VY Canis Majoris with VERA |first1 = Y. K. | last1 = Choi |bibcode=2008PASJ...60.1007C |last2 = Hirota | first2 = Tomoya |last3 = Honma | first3 = Mareki |last4 = Kobayashi | first4 = Hideyuki |last5 = Bushimata | first5 = Takeshi |last6 = Imai | first6 = Hiroshi |last7 = Iwadate | first7 = Kenzaburo |last8 = Jike | first8 = Takaaki |last9 = Kameno | first9 = Seiji |last10=Kameya |first10=O. |last11=Kamohara |first11=R. |last12=Kan-Ya |first12=Y. |last13=Kawaguchi |first13=N. |last14=Kijima |first14=M. |last15=Kim |first15=M. K. |last16=Kuji |first16=S. |last17=Kurayama |first17=T. |last18=Manabe |first18=S. |last19=Maruyama |first19=K. |last20=Matsui |first20=M. |last21=Matsumoto |first21=N. |last22=Miyaji |first22=T. |last23=Nagayama |first23=T. |last24=Nakagawa |first24=A. |last25=Nakamura |first25=K. |last26=Oh |first26=C. S. |last27=Omodaka |first27=T. |last28=Oyama |first28=T. |last29=Sakai |first29=S. |last30=Sasao |first30=T. |volume=60 |issue=5 |date=2008 |page=1007 |journal=Publications of the Astronomical Society of Japan|arxiv = 0808.0641 |doi = 10.1093/pasj/60.5.1007 |display-authors=29 }}</ref>

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<ref name="Monnier1999">{{cite journal | title = The Last Gasps of VY Canis Majoris: Aperture Synthesis and Adaptive Optics Imagery | last1 = Monnier | first1 = J. D. | last2 = Tuthill | first2 = P. | last3 = Lopez | first3 = GB | display-authors = 3 | date = 1999 | last4 = Cruzalebes | first4 = P. | last5 = Danchi | first5 = W. C. | last6 = Haniff | first6 = C. A. | journal = [[The Astrophysical Journal]] | volume = 512 | issue = 1 | pages = 351–361 | doi = 10.1086/306761 | bibcode = 1999ApJ...512..351M | arxiv = astro-ph/9810024}}</ref>
-->

<ref name="Alcolea">{{cite journal |doi=10.1051/0004-6361/201321683 |title=HIFISTARSHerschel/HIFI observations of VY Canis Majoris. Molecular-line inventory of the envelope around the largest known star|journal=Astronomy & Astrophysics |volume=559 |pages=A93 |year=2013 |last1=Alcolea |first1=J |last2=Bujarrabal |first2=V |last3=Planesas |first3=P |last4=Teyssier |first4=D |last5=Cernicharo |first5=J |last6=De Beck |first6=E |last7=Decin |first7=L |last8=Dominik |first8=C |last9=Justtanont |first9=K |last10=De Koter |first10=A |last11=Marston |first11=A. P |last12=Melnick |first12=G |last13=Menten |first13=K. M |last14=Neufeld |first14=D. A |last15=Olofsson |first15=H |last16=Schmidt |first16=M |last17=Schöier |first17=F. L |last18=Szczerba |first18=R |last19=Waters |first19=L. B. F. M |arxiv=1310.2400 |bibcode=2013A&A...559A..93A }}</ref>

<ref name=flux>{{cite journal|bibcode=2002yCat.2237....0D|title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system|journal=Vizier Online Data Catalog|last1=Ducati|first1=J. R|year=2002}}</ref>

<ref name=massey2008>{{cite journal|bibcode=2008IAUS..250...97M|title=The Physical Properties of Red Supergiants: Comparing Theory and Observations|journal=Massive Stars as Cosmic Engines|volume=250|pages=97|last1=Massey|first1=Philip|last2=Levesque|first2=Emily M|last3=Plez|first3=Bertrand|last4=Olsen|first4=Knut A. G|last5=Bresolin|first5=F|last6=Crowther|first6=P. A|last7=Puls|first7=J|year=2008|arxiv=0801.1806|doi=10.1017/S1743921308020383}}</ref>

<ref name=kaminski>{{cite journal|bibcode=2013A&A...551A.113K|title=Pure rotational spectra of TiO and TiO<sub>2</sub> in VY Canis Majoris|journal=Astronomy and Astrophysics|volume=551|issue=2013|pages=A113|last1=Kamiński|first1=T|last2=Gottlieb|first2=C. A|last3=Menten|first3=K. M|last4=Patel|first4=N. A|last5=Young|first5=K. H|last6=Brünken|first6=S|last7=Müller|first7=H. S. P|last8=McCarthy|first8=M. C|last9=Winters|first9=J. M|last10=Decin|first10=L|year=2013|arxiv=1301.4344|class=astro-ph.SR|doi=10.1051/0004-6361/201220290}}</ref>

<ref name=hipparcos1997>{{Cite journal|bibcode=1997HIP...C......0E}}</ref>

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<ref name=josselin>Table 1 in {{Cite journal|bibcode=2000A&A...357..225J|title=Observational investigation of mass loss of M supergiants|journal=Astronomy and Astrophysics|volume=357|pages=225|last1=Josselin|first1=E|last2=Blommaert|first2=J. A. D. L|last3=Groenewegen|first3=M. A. T|last4=Omont|first4=A|last5=Li|first5=F. L|year=2000}}</ref>
-->

<ref name=humphreys2017>{{Cite journal|arxiv=1704.02133|last1=Humphreys|first1=E. M. L|title=Simultaneous 183 GHz H2O Maser and SiO Observations Towards Evolved Stars Using APEX SEPIA Band 5|journal=Astronomy & Astrophysics|volume=603|pages=A77|last2=Immer|first2=K|last3=Gray|first3=M. D|last4=De Beck|first4=E|last5=Vlemmings|first5=W. H. T|last6=Baudry|first6=A|last7=Richards|first7=A. M. S|last8=Wittkowski|first8=M|last9=Torstensson|first9=K|last10=De Breuck|first10=C|last11=Moller|first11=P|last12=Etoka|first12=S|last13=Olberg|first13=M|doi=10.1051/0004-6361/201730718|year=2017|bibcode=2017A&A...603A..77H}}</ref>

<!--
<ref name=marco2013>{{cite journal|bibcode=2013A&A...552A..92M|title=NGC 7419 as a template for red supergiant clusters|journal=Astronomy and Astrophysics|volume=552|pages=A92|last1=Marco|first1=A|last2=Negueruela|first2=I|year=2013|arxiv=1302.5649|class=astro-ph.SR|doi=10.1051/0004-6361/201220750}}</ref>
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<ref name="apj137">{{cite journal
  | title=Red Supergiants as Potential Type IIn Supernova Progenitors: Spatially Resolved 4.6 μm CO Emission Around VY CMa and Betelgeuse
  |author1=Smith, Nathan |author2=Hinkle, Kenneth H. |author3=Ryde, Nils | journal=The Astronomical Journal| volume=137 | issue=3
  | pages=3558–3573|date=March 2009
  | doi=10.1088/0004-6256/137/3/3558 | bibcode=2009AJ....137.3558S
|arxiv = 0811.3037 }}</ref>

<ref name=hipparcos>{{cite journal|bibcode=2007A&A...474..653V|title=Validation of the new Hipparcos reduction|journal=Astronomy and Astrophysics|volume=474|issue=2|pages=653–664|author1=Van Leeuwen|first1=F.|year=2007|doi=10.1051/0004-6361:20078357|arxiv = 0708.1752 }}</ref>

<ref name=GCVS-VY-CMa>{{cite web |title=GCVS Query=VY CMa |publisher=[[General Catalogue of Variable Stars]] @ [[Centre de données astronomiques de Strasbourg|Sternberg Astronomical Institute, Moscow, Russia]] |url=http://www.sai.msu.su/gcvs/cgi-bin/search.cgi?search=VY+CMa |accessdate=2010-11-24}}</ref>

<ref name=AAVSO-VY-CMa>{{cite web |title=VSX: Detail for VY CMa |publisher=[[American Association of Variable Star Observers]] |url=https://www.aavso.org/vsx/index.php?view=detail.top&oid=5196 |accessdate=2018-07-20}}</ref>

<ref name=ejecta>{{cite journal|doi=10.1086/517609|title=The Three-Dimensional Morphology of VY Canis Majoris. I. The Kinematics of the Ejecta|journal=The Astronomical Journal|volume=133|issue=6|pages=2716–2729|year=2007|last1=Humphreys|first1=Roberta M.|last2=Helton|first2=L. Andrew|last3=Jones|first3=Terry J.|bibcode=2007AJ....133.2716H|arxiv = astro-ph/0702717 }}</ref>

<ref name=zhang>{{cite journal | title = Distance and Kinematics of the Red Hypergiant VY CMa: VLBA and VLA Astrometry | date = January 2012 | arxiv = 1109.3036 | origyear = 14 Sep 2011 (v1) | last1 = Zhang | first1 = B. | last2 = Reid | first2 = M. J. | last3 = Menten | first3 = K. M. | last4 = Zheng | first4 = X. W. | journal = [[The Astrophysical Journal]] | volume = 744 | issue = 1 | page = 23 | doi = 10.1088/0004-637X/744/1/23 |bibcode = 2012ApJ...744...23Z }}</ref>

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<ref name="Monnier1998">{{cite journal | doi = 10.1086/305945 | last1 = Monnier | first1 = J. D. | last2 = Geballe | first2 = T. R. | last3 = Danchi | first3 = W. C. | title = Temporal variations of midinfrared spectra in late-type stars | journal = The Astrophysical Journal | volume = 502 | issue = 2 | pages = 833–846 | date = 1 August 1998 | bibcode=1998ApJ...502..833M|arxiv = astro-ph/9803027 }}</ref>
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<ref name=sidaner>{{cite journal | bibcode = 1996A&A...314..896L| title = Optical and infrared observations of 27 oxygen-rich stars. Modelling of the circumstellar dust shells| journal = Astronomy and Astrophysics| volume = 314| pages = 896| last1 = Le Sidaner| first1 = P| last2 = Le Bertre| first2 = T| year = 1996}}</ref>

<ref name=knapp>{{cite journal|bibcode=1993ApJS...88..173K|title=The Dust Content of Evolved Circumstellar Envelopes and the Optical Properties of Dust at Submillimeter to Radio Wavelengths|journal=The Astrophysical Journal Supplement Series|volume=88|pages=173|last1=Knapp|first1=G. R|last2=Sandell|first2=G|last3=Robson|first3=E. I|year=1993|doi=10.1086/191820}}</ref>

<ref name="Robinson">{{cite journal|bibcode=1971IBVS..599....1R|title=Three Somewhat Overlooked Facets of VY Canis Majoris|journal=Information Bulletin on Variable Stars|volume=599|pages=1|author1=Robinson|first1=L. J.|year=1971}}</ref>

<ref name="Sh2-310">{{cite web|website=Galaxy Map|url=http://galaxymap.org/cgi-bin/details.py?id=21671&t=hii&s=4_p23.5xp26.5&name=S310|title=Result for Sh-2 310|accessdate=20 August 2018}}</ref>

<ref name=roberta>{{Cite journal|doi=10.1086/426565|title=High-Resolution, Long-Slit Spectroscopy of VY Canis Majoris: The Evidence for Localized High Mass Loss Events|journal=The Astronomical Journal|volume=129|issue=1|pages=492–510|year=2005|last1=Humphreys|first1=Roberta M|last2=Davidson|first2=Kris|last3=Ruch|first3=Gerald|last4=Wallerstein|first4=George|bibcode=2005AJ....129..492H}}</ref>

<ref name="Wittkowski">{{cite journal|bibcode=1998A&A...340L..39W|title=Diffraction-limited speckle-masking interferometry of the red supergiant VY CMa|journal=Astronomy and Astrophysics|volume=340|issue=2004|pages=77–87|author1=Wittkowski|first1=M.|last2=Langer|first2=N.|last3=Weigelt|first3=G.|year=1998|arxiv = astro-ph/9811280 }}</ref>

<ref name=hoffmeister>{{cite journal|bibcode=1931AN....242..129H|title=316 neue Veränderlilche|journal=Astronomische Nachrichten|volume=242|issue=7|pages=129–142|author1=Hoffmeister|first1=Cuno|year=1931|doi=10.1002/asna.19312420702}}</ref>

<ref name=guthnick>{{cite journal|bibcode=1939AN....268..165G|title=Benennung von veränderlichen Sternen|journal=Astronomische Nachrichten|volume=268|issue=11–12|pages=165|author1=Guthnick|first1=P.|last2=Schneller|first2=H.|year=1939|doi=10.1002/asna.19392681102}}</ref>

<ref name=wallerstein>{{cite journal|bibcode=1958PASP...70..479W|title=The Spectrum of the Irregular Variable VY Canis Majoris|journal=Publications of the Astronomical Society of the Pacific|volume=70|issue=416|pages=479|author1=Wallerstein|first1=George|year=1958|doi=10.1086/127278}}</ref>

<ref name=skiff>{{cite journal|bibcode=2014yCat....1.2023S|title=VizieR Online Data Catalog: Catalogue of Stellar Spectral Classifications (Skiff, 2009-2016)|journal=VizieR On-line Data Catalog: B/mk.  Originally Published In: Lowell Observatory (October 2014)|volume=1|pages=B/mk|author1=Skiff|first1=B. A.|year=2014}}</ref>

<ref name="LadaReid2">{{cite journal | doi = 10.1086/155758 | last1 = Lada | first1 = Charles J. | last2 = Reid | first2 = Mark J. | title = CO observations of a molecular cloud complex associated with the bright rim near VY Canis Majoris | journal = The Astrophysical Journal | volume = 219 | pages = 95–104 | date = 1 January 1978 | bibcode=1978ApJ...219...95L}}</ref>

<ref name="levesque">{{Cite journal|last1=Levesque|first1=Emily M.|last2=Massey|first2=Philip|last3=Olsen|first3=K. A. G.|last4=Plez|first4=Bertrand|last5=Josselin|first5=Eric|last6=Maeder|first6=Andre|last7=Meynet|first7=Georges|year=2005|title=The Effective Temperature Scale of Galactic Red Supergiants: Cool, but Not as Cool as We Thought|journal=The Astrophysical Journal|volume=628|issue=2|pages=973–985|arxiv=astro-ph/0504337|bibcode=2005ApJ...628..973L|doi=10.1086/430901|pmc=|pmid=}}</ref>

<ref name=monnier>{{cite journal|bibcode=2004ApJ...605..436M|arxiv=astro-ph/0401363|title=High-Resolution Imaging of Dust Shells by Using Keck Aperture Masking and the IOTA Interferometer|journal=The Astrophysical Journal|volume=605|issue=1|pages=436–461|author1=Monnier|first1=J. D|last2=Millan-Gabet|first2=R|last3=Tuthill|first3=P. G|last4=Traub|first4=W. A|last5=Carleton|first5=N. P|last6=Coudé Du Foresto|first6=V|last7=Danchi|first7=W. C|last8=Lacasse|first8=M. G|last9=Morel|first9=S|last10=Perrin|first10=G|last11=Porro|first11=I. L|last12=Schloerb|first12=F. P|last13=Townes|first13=C. H|year=2004|doi=10.1086/382218}}</ref>

<ref name=zubko>{{cite journal|bibcode=2004ApJ...610..427Z|arxiv=astro-ph/0405044|title=Observations of Water Vapor Outflow from NML Cygnus|journal=The Astrophysical Journal|volume=610|issue=1|pages=427–435|author1=Zubko|first1=Viktor|last2=Li|first2=Di|last3=Lim|first3=Tanya|last4=Feuchtgruber|first4=Helmut|last5=Harwit|first5=Martin|year=2004|doi=10.1086/421700}}</ref>

<ref name="Melnik">{{cite journal | last1 = Mel'nik | first1 = A.M. | last2 = Dambis | first2 = A.K.| journal= [[Monthly Notices of the Royal Astronomical Society]] | volume = 400 | issue = 1 | pages = 518–523 | doi = 10.1111/j.1365-2966.2009.15484.x | title = Kinematics of OB-associations and the new reduction of the Hipparcos data | date = 2009|arxiv = 0909.0618 |bibcode = 2009MNRAS.400..518M }}</ref>

<ref name="LadaReid76">{{cite journal|bibcode=1976BAAS....8R.322L|title=The Discovery of a Molecular Cloud Associated with VY CMa|journal=Bulletin of the American Astronomical Society|volume=8|pages=322|author1=Lada|first1=C. J.|last2=Reid|first2=M.|year=1976}}</ref>

<ref name=mikako>{{Cite journal|arxiv=1608.01729|last1=Matsuura|first1=Mikako|title=The mass-loss rates of red supergiants at low metallicity: Detection of rotational CO emission from two red supergiants in the Large Magellanic Cloud|journal=Monthly Notices of the Royal Astronomical Society|volume=462|issue=3|pages=2995–3005|last2=Sargent|first2=B|last3=Swinyard|first3=Bruce|last4=Yates|first4=Jeremy|last5=Royer|first5=P|last6=Barlow|first6=M. J|last7=Boyer|first7=Martha|last8=Decin|first8=L|last9=Khouri|first9=Theo|last10=Meixner|first10=Margaret|last11=van Loon|first11=Jacco Th|last12=Woods|first12=Paul M|doi=10.1093/mnras/stw1853|year=2016|bibcode=2016MNRAS.462.2995M}}</ref>

<ref name="Nathan2001">{{cite journal
 | last1 = Smith | first1 = Nathan
 | last2 = Humphreys | first2 = Roberta M.
 | last3 = Davidson | first3 = Kriz
 | last4 = Gehrz | first4 = Robert D.
 | last5 = Schuster | first5 = M. T.
 | last6 = Krautter | first6 = Joachim
 | title = The Asymmetric Nebula Surrounding the Extreme Red Supergiant Vy Canis Majoris
 | journal = The Astronomical Journal | volume = 121
 | issue = 2 | pages = 1111–1125
 | date = February 2001 | doi = 10.1086/318748 | bibcode = 2001AJ....121.1111S}}
</ref>

<ref name="LipscyJura2005">{{cite journal | doi = 10.1086/429900 | last1 = Lipscy | first1 = S. J. | last2 = Jura | first2 = M. | last3 = Reid | first3 = M. J. | title = Radio photosphere and mass-loss envelope of VY Canis Majoris | journal = The Astrophysical Journal | volume = 626 | issue = 1 | pages = 439–445 | date = 10 June 2005 | bibcode=2005ApJ...626..439L|arxiv = astro-ph/0502586 }}</ref>

<ref name=debeck>{{cite journal|bibcode=2010A&A...523A..18D|arxiv=1008.1083|title=Probing the mass-loss history of AGB and red supergiant stars from CO rotational line profiles. II. CO line survey of evolved stars: Derivation of mass-loss rate formulae|journal=Astronomy and Astrophysics|volume=523|pages=A18|author1=De Beck|first1=E.|last2=Decin|first2=L.|last3=De Koter|first3=A.|last4=Justtanont|first4=K.|last5=Verhoelst|first5=T.|last6=Kemper|first6=F.|last7=Menten|first7=K. M.|year=2010|doi=10.1051/0004-6361/200913771}}</ref>

<ref name=opacity>{{cite paper | bibcode = 1991A&A...246..374B | title = The parameters R and Teff in stellar models and observations | last1 = Wehrse | first1 = R. | last2 = Scholz | first2 = M. | last3 = Baschek | first3 = B. | journal = [[Astronomy and Astrophysics]] | date = June 1991 | volume = 246 | issue = 2 | pages = 374–382 }}</ref>

<ref name=SSE>{{cite web|title=Solar System Exploration: Planets: Sun: Facts & Figures |url=http://solarsystem.nasa.gov/planets/profile.cfm?Object=Sun&Display=Facts&System=Metric |publisher=[[NASA]] |accessdate=15 January 2016 |deadurl=yes |archiveurl=https://web.archive.org/web/20080102034758/http://solarsystem.nasa.gov/planets/profile.cfm?Object=Sun&Display=Facts&System=Metric |archivedate=January 2, 2008 }}</ref>

<ref name=chicago1969>{{Cite journal|bibcode=1969ApJ...156L.139S|title=Large Optical Polarization of the OH Emission Source VY Canis Majoris|journal=The Astrophysical Journal|volume=156|pages=L139|last1=Serkowski|first1=K|year=1969|doi=10.1086/180366}}</ref>

<ref name=herbig>{{Cite journal|bibcode=1970ApJ...162..557H|title=VY Canis Majoris. II. Interpretation of the Energy Distribution|journal=The Astrophysical Journal|volume=162|pages=557|last1=Herbig|first1=G. H|year=1970}}</ref>

<ref name=debeck2015>{{Cite journal|bibcode=2015A&A...580A..36D|title=ALMA observations of TiO<SUB>2</SUB> around VY Canis Majoris|journal=Astronomy and Astrophysics|volume=580|pages=A36|last1=De Beck|first1=E|last2=Vlemmings|first2=W|last3=Muller|first3=S|last4=Black|first4=J. H|last5=O'Gorman|first5=E|last6=Richards|first6=A. M. S|last7=Baudry|first7=A|last8=Maercker|first8=M|last9=Decin|first9=L|last10=Humphreys|first10=E. M|year=2015|doi=10.1051/0004-6361/201525990}}</ref>

<ref name=sharpless>{{Cite journal|doi=10.1086/190049|title=A Catalogue of H II Regions|journal=The Astrophysical Journal Supplement Series|volume=4|pages=257|year=1959|last1=Sharpless|first1=Stewart}}</ref>

<ref name=george>{{Cite journal|bibcode=1978Obs....98..224W|title=An interpretation of the apparent orbit of VY CMa AB: The rotating holey dust cloud hypothesis|journal=The Observatory|volume=98|pages=224|last1=Wallerstein|first1=G|year=1978}}</ref>

<ref name=wilson1975>{{Cite journal|bibcode=1975ApJ...197..329S|title=Detection of new stellar sources of vibrationally excited silicon monoxide maser emission at 6.95 millimeters|journal=The Astrophysical Journal|volume=197|pages=329|last1=Snyder|first1=L. E|last2=Buhl|first2=D|year=1975|doi=10.1086/153517}}</ref>

<ref name=bartlett1969>{{Cite journal|bibcode=1969ApJ...155L..79E|title=Discovery of an Intense OH Emission Source|journal=The Astrophysical Journal|volume=155|pages=L79|last1=Eliasson|first1=B|last2=Bartlett|first2=J. F|year=1969|doi=10.1086/180306}}</ref>

<ref name=wilson>{{Cite journal|bibcode=1968Sci...161..778W|title=Discovery of Hydroxyl Radio Emission from Infrared Stars|journal=Science|volume=161|issue=3843|pages=778–9|last1=Wilson|first1=William J|last2=Barrett|first2=Alan H|year=1968|doi=10.1126/science.161.3843.778|pmid=17802620}}</ref>

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<ref name=tycho2>{{Cite book|bibcode=2000A&A...355L..27H|title=The Tycho-2 catalogue of the 2.5 million brightest stars|journal=Astronomy and Astrophysics|volume=355|pages=L27|author1=Høg|first1=E.|last2=Fabricius|first2=C.|last3=Makarov|first3=V. V.|last4=Urban|first4=S.|last5=Corbin|first5=T.|last6=Wycoff|first6=G.|last7=Bastian|first7=U.|last8=Schwekendiek|first8=P.|last9=Wicenec|first9=A.|year=2000|doi=10.1888/0333750888/2862|isbn=978-0333750889}}</ref>
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<ref name=mauron>{{cite journal|bibcode=2011A&A...526A.156M|arxiv=1010.5369|title=The mass-loss rates of red supergiants and the de Jager prescription|journal=Astronomy and Astrophysics|volume=526|pages=A156|author1=Mauron|first1=N.|last2=Josselin|first2=E.|date=2011|doi=10.1051/0004-6361/201013993}}</ref>

<ref name=jay>{{Cite journal|arxiv=1512.01529|last1=Shenoy|first1=Dinesh|title=Searching for Cool Dust in the Mid-to-Far Infrared: The Mass Loss Histories of the Hypergiants μ Cep, VY CMa, IRC+10420, and ρ Cas|journal=The Astronomical Journal|volume=151|issue=3|pages=51|last2=Humphreys|first2=Roberta M|author3=Terry Jay Jones|last4=Marengo|first4=Massimo|last5=Gehrz|first5=Robert D|last6=Andrew Helton|first6=L|last7=Hoffmann|first7=William F|last8=Skemer|first8=Andrew J|last9=Hinz|first9=Philip M|year=2015|doi=10.3847/0004-6256/151/3/51|bibcode=2016AJ....151...51S}}</ref>

<ref name=joel1996>{{Cite journal|bibcode=1996hst..prop.6416K|title=FOC Imaging of the Dusty Envelopes of Mass-Losing Supergiants|journal=Hst Proposal|pages=6416|last1=Kastner|first1=Joel|year=1996}}</ref>

<ref name=aavso>{{Cite web|url=http://www.aavso.org/vsots_vycma | title=VY Canis Majoris | website=American Association of Variable Star Observers | date=13 April 2010}}</ref>

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<ref name=Monnier2000>{{cite journal|bibcode=2000ApJ...543..861M|title=Mid-Infrared Interferometry on Spectral Lines. II. Continuum (Dust) Emission Around IRC +10216 and VY Canis Majoris|journal=The Astrophysical Journal|volume=543|issue=2|pages=861|arxiv=astro-ph/0007393|doi=10.1086/317126|year=2000|last1=Monnier|first1=J. D|last2=Danchi|first2=W. C|last3=Hale|first3=D. S|last4=Lipman|first4=E. A|last5=Tuthill|first5=P. G|last6=Townes|first6=C. H}}</ref>
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<ref name="konkoly">{{cite web | publisher=www.konkoly.hu | title=VY CANIS MAJORIS -- A UNIQUE VARIABLE | url=http://www.konkoly.hu/pub/ibvs/0401/0465.txt |date=11 September 1970 | accessdate=21 August 2018}}</ref>
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<ref name="molecules">{{cite web | authors=David Darling | title=VY Canis Majoris | url=http://www.daviddarling.info/encyclopedia/V/VY_Canis_Majoris.html | accessdate=9 July 2018}}</ref>

<ref name="hubble">{{cite web | website=HubbleSite | title=Astronomers Map a Hypergiant Star's Massive Outbursts | url=http://hubblesite.org/news_release/news/2007-03 |date=8 January 2007 | accessdate=9 July 2018}}</ref>

<ref name=dr2>{{cite DR2|5616197646838713728}}</ref>

}}
[[Category:Semiregular variable stars]]
[[Category:Stars of Canis Major]]
[[Category:Extreme stars]]
[[Category:Stars]]
[[Category:Astronomy]]
[[Category:M-type hypergiants]]
[[Category:Variable stars]]
[[Category:Stars with uncertain parameters]]
{{#description2:red hypergiant in the constellation Canis Major}}
{{The 10 largest stars by radius}}{{Good article}}
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