VY Canis Majoris - wikipedia VY Canis Majoris VY Canis Majoris Actual image of VY Canis Majoris ( brightest star in the image ) and its surrounding molecular cloud complex in the open cluster NGC 2362 as seen from the Rutherfurd Observatory of the Columbia University in New York, United States on the evening of 7 September 2014, Sunday. Observation data Epoch J2000 Equinox J2000 Constellation Canis Major Right ascension 07 22 58.32877 Declination − 25 ° 46 ′ 03.2355 '' Apparent magnitude ( V ) 6.5 to 9.6 Characteristics Spectral type ( M2. 5I - ) M3 - M4. 5 Variable type Semiregular Astrometry Radial velocity ( R ) 41 km / s Proper motion ( μ ) RA : 9.84 mas / yr Dec. : 0.75 mas / yr Parallax ( π ) 0.83 ± 0.1 mas Distance ~ 3,840 ly ( 1,170 pc ) Details Mass 17 ± 8 M Radius 1,420 ± 120 R Luminosity ~ 270,000 L Surface gravity ( log g ) - 0.6 cgs Temperature ~ 3,490 ± 90 K Other designations VY CMa, HD 58061, HIP 35793, CD - 25 4441, AAVSO 0718 - 25 Database references SIMBAD data VY Canis Majoris ( VY CMa ) is a red hypergiant star located in the constellation Canis Major. It is one of the largest stars ( at one time it was the largest known ) and also one of the most luminous of its type. It has a radius of approximately 1,420 solar radii ( 990,000,000 km ; 6.6 au ), and is 17 ± 8 times as massive as the Sun. Located about 1.2 kiloparsecs ( 3,900 light - years ) from Earth, it is too faint to be seen with the naked eye. VY Canis Majoris is a single star categorized as a semiregular variable with an estimated period of 2,000 days. It has an average density of 5 to 10 mg / m. If placed at the center of the Solar System, VY Canis Majoris 's surface would extend beyond the orbit of Jupiter, although there is still considerable variation in estimates of the radius. Contents 1 Observational history 2 Spectrum 3 Properties 3.1 Luminosity 3.2 Size 4 Distance 5 Surroundings 6 Controversy 7 See also 8 References 9 Further reading 10 External links Observational history The first known recorded observation of VY Canis Majoris is in the star catalogue of Jérôme Lalande, on 7 March 1801, which lists it as a 7th magnitude star. Further 19th - century studies of its apparent magnitude demonstrate that the star has been fading since 1850. Since 1847, VY Canis Majoris has been described as a crimson star. During the 19th century, observers measured at least six discrete components, suggesting that it might be a multiple star. These discrete components are now known to be bright areas in the surrounding nebula. Visual observations in 1957 and high - resolution imaging in 1998 showed that there are no companion stars. The varying brightness of VY Cma was not described until 1931 when it was listed ( in German ) as a long period variable with a photographic magnitude range of 9.5 - 11.5. It was given the variable star designation VY CMa in 1939. Spectrum The spectrum of VY CMa is that of a luminous class M star. The hydrogen lines have P Cygni profiles. The spectrum is dominated by TiO bands whose strength suggests a classification of M5. The H line is not seen and there are unusual emission lines of neutral sodium and calcium. The luminosity class as determined from different spectral features varies from bright giant ( II ) to bright supergiant ( Ia ), with a compromise being given as M5eIbp. Early attempts at classification were confused by the interpretation of surrounding nebulosity as companion stars. The derived spectral class varies depending on the features examined. The spectral features also vary over time. It is considered to be unambiguously cooler than M2 and is usually classified between M3 and M4. Classes as extreme as M2. 5 and M5 have been given. The luminosity class is likewise confused and often given only as I. Properties VY Canis Majoris is a high - luminosity M star with an effective temperature of about 3,500 K, placing it at the upper - right hand corner of the Hertzsprung -- Russell diagram and meaning it is a highly evolved star. During its main sequence, it would have been an O - type star with a mass of 15 to 35 M. Luminosity In 2006, University of Minnesota Professor Roberta M. Humphreys used the spectral energy distribution distance of VY Canis Majoris to calculate its luminosity. Since most of the radiation coming from the star is reprocessed by the dust in the surrounding cloud, she integrated the total fluxes over the entire nebula and showed that VY Canis Majoris has a luminosity of 7005560000000000000 ♠ 5.6 × 10 L. More recent estimates of the luminosity using a variety of methods give lower values of around 7005300000000000000 ♠ 3 × 10 L. Size Humphreys originally estimated the radius of VY CMa at 1,800 - 2,100 solar radii. A more recent and accurate VLTI measurement gives the star a radius of 1,420 ± 120 solar radii. Earlier direct measurements of the radius at infrared wavelengths gave values above 2,800 R, but this is probably larger than size of the underlying star. Distance Right to left : VY Canis Majoris compared to Betelgeuse, Rho Cassiopeiae, the Pistol Star, and the Sun ( too small to be visible in this thumbnail ). The orbits of Jupiter and Neptune are also shown. In 1976, Charles J. Lada and Mark J. Reid published the discovery of a bright - rimmed molecular cloud 15 minutes of arc east of VY Canis Majoris. At the edge of the cloud bordered by the bright rim, an abrupt decrease in the CO emission and an increase in brightness of the 12 CO emission were observed, indicating possible destruction of molecular material and enhanced heating at the cloud - rim interface, respectively. Lada and Reid assumed the distance of the molecular cloud is approximately equal to that of the stars, which are members of the open cluster NGC 2362, that ionize the rim. NGC 2362 has a distance of 1.5 ± 0.5 kiloparsecs as determined from its color - magnitude diagram. VY CMa is projected onto the tip of the cloud rim, suggesting its association with the molecular cloud. In addition to that, the velocity of the molecular cloud is very close to the velocity of the star. This further indicates the association of the star with the molecular cloud, and consequently with NGC 2362, which means VY Canis Majoris is at the same distance. A more recent measurement of the distance to NGC 2362 gives 1.2 kiloparsecs. Stellar distances can be calculated by measuring parallaxes as Earth orbits around the Sun. However, VY Canis Majoris has a tiny parallax due to its great distance, and standard visual observations such as by Hipparcos have too great a margin of error to be useful. VLBI measurements of the parallax of VY Canis Majoris using H O masers are much more accurate and give a distance of 7000113999999999999 ♠ 1.14 + 0.11 − 0.09 kiloparsecs ( kpc ). VLBI measurements using SiO masers give a distance of 7000120000000000000 ♠ 1.20 + 0.13 − 0.10 kpc. The Gaia mission should provide visual parallaxes with even better accuracy. Surroundings VY Canis Majoris ejects huge amounts of gas during its outbursts. Image taken by the ESO 's Very Large Telescope. VY Canis Majoris is surrounded by an extensive nebula, which contains condensations that were once regarded as companion stars. The nebula has been extensively studied with the aid of the Hubble Space Telescope. It has a complex structure that includes filaments and arcs, which were caused by past eruptions ; this structure is similar to that of the nebula surrounding the yellow hypergiant IRC + 10420. The similarity has led astronomers to propose that VY CMa will itself become a yellow hypergiant, then a luminous blue variable, and finally a Wolf -- Rayet star, if it does not explode as a supernova first. Multiple asymmetric mass loss events are deduced to have occurred within the last 1,000 years. The mass loss is due to strong convection in the tenuous outer layers of the star, associated with magnetic fields. This is similar to the sunspots and coronal ejections of the Sun but on a much larger scale. Controversy VY Canis Majoris is a Class M hypergiant. Its true size is uncertain. Artist 's impression. There have been conflicting opinions of the properties of VY CMa. In one view, the star is a very large and very luminous red hypergiant. The various larger estimates of the size and luminosity fall outside the bounds of current stellar theory, both beyond the maximum predicted size of any star and far cooler than a star of its luminosity can become. In another opinion ( such as Massey, Levesque, and Plez 's study ), the star is a normal red supergiant, with a radius around 600 solar radii and falling comfortably inside models of stellar structure and evolution. More recent papers produce intermediate values for radius and luminosity, falling at the very extreme for the expected size and luminosity of red supergiants ( or hypergiant based on its emission spectrum and high mass loss rate ). VY Canis Majoris also illustrates the problem of defining the `` surface '' ( and so the radius ) of very large stars. With an average density of 0.000005 to 0.000010 kg / m, the star is a hundred thousand times less dense than the atmosphere of Earth at sea level. It is also undergoing strong mass loss with the outer layers of the star no longer gravitationally bound. The definition of the boundary of such stars is based on the Rosseland Radius, the location at which the optical depth is one ( or sometimes a different value such as 2 / 3 ). In cases such as VY CMa, the radius may be defined on a different opacity value or on an opacity at a particular wavelength. See also Relative sizes of some planets in the Solar System and several well - known stars, including VY Canis Majoris 1. Mercury < Mars < Venus < Earth 2. Earth < Neptune < Uranus < Saturn < Jupiter 3. Jupiter < Proxima Centauri < Sun < Sirius 4. Sirius < Pollux < Arcturus < Aldebaran 5. Aldebaran < Rigel < Antares < Betelgeuse 6. Betelgeuse < VY Canis Majoris < NML Cygni < UY Scuti. Star portal Orders of magnitude ( length ) HD 100546 b R136a1 VV Cephei A NML Cygni UY Scuti Westerlund 1 - 26 WOH G64 Mu Cephei V354 Cephei References ^ Jump up to : Van Leeuwen, F. ( 2007 ). `` Validation of the new Hipparcos reduction ''. Astronomy and Astrophysics. 474 ( 2 ) : 653. Bibcode : 2007A&A... 474... 653V. arXiv : 0708.1752. doi : 10.1051 / 0004 - 6361 : 20078357. Jump up ^ `` GCVS Query = VY CMa ''. General Catalogue of Variable Stars @ Sternberg Astronomical Institute, Moscow, Russia. Retrieved 2010 - 11 - 24. ^ Jump up to : Massey, Philip ; Levesque, Emily M. ; Plez, Bertrand ( 1 August 2006 ). `` Bringing VY Canis Majoris down to size : an improved determination of its effective temperature ''. The Astrophysical Journal. 646 ( 2 ) : 1203 -- 1208. Bibcode : 2006ApJ... 646.1203 M. arXiv : astro - ph / 0604253. doi : 10.1086 / 505025. ^ Jump up to : Wittkowski, M. ; Hauschildt, P.H. ; Arroyo - Torres, B. ; Marcaide, J.M. ( 5 April 2012 ). `` Fundamental properties and atmospheric structure of the red supergiant VY CMa based on VLTI / AMBER spectro - interferometry ''. Astronomy & Astrophysics. 540 : L12. Bibcode : 2012A&A... 540L... 12W. arXiv : 1203.5194. doi : 10.1051 / 0004 - 6361 / 201219126. Jump up ^ Monnier, J.D. ; Geballe, T.R. ; Danchi, W.C. ( 1 August 1998 ). `` Temporal variations of midinfrared spectra in late - type stars ''. The Astrophysical Journal. American Astronomical Society. 502 ( 2 ) : 833 -- 846. Bibcode : 1998ApJ... 502... 833M. arXiv : astro - ph / 9803027. doi : 10.1086 / 305945. ^ Jump up to : Humphreys, Roberta M. ; Helton, L. Andrew ; Jones, Terry J. ( 2007 ). `` The Three - Dimensional Morphology of VY Canis Majoris. I. The Kinematics of the Ejecta ''. The Astronomical Journal. 133 ( 6 ) : 2716. Bibcode : 2007AJ... 133.2716 H. arXiv : astro - ph / 0702717. doi : 10.1086 / 517609. ^ Jump up to : Zhang, B. ; Reid, M.J. ; Menten, K.M. ; Zheng, X.W. ( January 2012 ) ( 14 Sep 2011 ( v1 ) ). `` Distance and Kinematics of the Red Hypergiant VY CMa : VLBA and VLA Astrometry ''. The Astrophysical Journal. 744 ( 1 ) : 23. Bibcode : 2012ApJ... 744... 23Z. arXiv : 1109.3036. doi : 10.1088 / 0004 - 637X / 744 / 1 / 23. ^ Jump up to : Robinson, L.J. ( 1971 ). `` Three Somewhat Overlooked Facets of VY Canis Majoris ''. Information Bulletin on Variable Stars. 599 : 1. Bibcode : 1971IBVS... 599... 1R. ^ Jump up to : Wittkowski, M. ; Langer, N. ; Weigelt, G. ( 1998 ). `` Diffraction - limited speckle - masking interferometry of the red supergiant VY CMa ''. Astronomy and Astrophysics. 340 : L39. Bibcode : 1998A&A... 340L... 39W. arXiv : astro - ph / 9811280. Jump up ^ Hoffmeister, Cuno ( 1931 ). `` 316 neue Veränderlilche ''. Astronomische Nachrichten. 242 ( 7 ) : 129. Bibcode : 1931AN... 242... 129H. doi : 10.1002 / asna. 19312420702. Jump up ^ Guthnick, P. ; Schneller, H. ( 1939 ). `` Benennung von veränderlichen Sternen ''. Astronomische Nachrichten. 268 ( 11 -- 12 ) : 165. Bibcode : 1939AN... 268... 165G. doi : 10.1002 / asna. 19392681102. Jump up ^ Wallerstein, George ( 1958 ). `` The Spectrum of the Irregular Variable VY Canis Majoris ''. Publications of the Astronomical Society of the Pacific. 70 : 479. Bibcode : 1958PASP... 70... 479W. doi : 10.1086 / 127278. Jump up ^ Skiff, B.A. ( 2014 ). `` VizieR Online Data Catalog : Catalogue of Stellar Spectral Classifications ( Skiff, 2009 - 2016 ) ''. VizieR On - line Data Catalog : B / mk. Originally published in : Lowell Observatory ( October 2014 ). 1. Bibcode : 2014yCat... 1.2023 S. ^ Jump up to : Lada, Charles J. ; Reid, Mark J. ( 1 January 1978 ). `` CO observations of a molecular cloud complex associated with the bright rim near VY Canis Majoris ''. The Astrophysical Journal. American Astronomical Society. 219 : 95 -- 104. Bibcode : 1978ApJ... 219... 95L. doi : 10.1086 / 155758. ^ Jump up to : Humphreys, Roberta M. ( 2006 ). `` VY Canis Majoris : The Astrophysical Basis of Its Luminosity '' : arXiv : astro -- ph / 0610433. Bibcode : 2006astro. ph. 10433H. arXiv : astro - ph / 0610433. Jump up ^ Humphreys, Roberta M ( 2006 ). `` VY Canis Majoris : The Astrophysical Basis of Its Luminosity '' : arXiv : astro -- ph / 0610433. Bibcode : 2006astro. ph. 10433H. arXiv : astro - ph / 0610433. Jump up ^ Lada, C.J. ; Reid, M. ( 1976 ). `` The Discovery of a Molecular Cloud Associated with VY CMa ''. Bulletin of the American Astronomical Society. 8 : 322. Bibcode : 1976BAAS... 8R. 322L. Jump up ^ Mel'nik, A.M. ; Dambis, A.K. ( 2009 ). `` Kinematics of OB - associations and the new reduction of the Hipparcos data ''. Monthly Notices of the Royal Astronomical Society. 400 : 518. Bibcode : 2009MNRAS. 400... 518M. arXiv : 0909.0618. doi : 10.1111 / j. 1365 - 2966.2009. 15484. x. Jump up ^ Choi, Y.K. ; Hirota, Tomoya ; Honma, Mareki ; Kobayashi, Hideyuki ; Bushimata, Takeshi ; Imai, Hiroshi ; Iwadate, Kenzaburo ; Jike, Takaaki ; Kameno, Seiji ; Kameya, O. ; Kamohara, R. ; Kan - Ya, Y. ; Kawaguchi, N. ; Kijima, M. ; Kim, M.K. ; Kuji, S. ; Kurayama, T. ; Manabe, S. ; Maruyama, K. ; Matsui, M. ; Matsumoto, N. ; Miyaji, T. ; Nagayama, T. ; Nakagawa, A. ; Nakamura, K. ; Oh, C.S. ; Omodaka, T. ; Oyama, T. ; Sakai, S. ; et al. ( 2008 ). `` Distance to VY VMa with VERA ''. Publications of the Astronomical Society of Japan. Publications Astronomical Society of Japan. 60 ( 5 ) : 1007. Bibcode : 2008PASJ... 60.1007 C. arXiv : 0808.0641. doi : 10.1093 / pasj / 60.5. 1007. Jump up ^ Smith, Nathan ; Humphreys, Roberta M. ; Davidson, Kriz ; Gehrz, Robert D. ; Schuster, M.T. ; Krautter, Joachim ( February 2001 ). `` The Asymmetric Nebula Surrounding the Extreme Red Supergiant Vy Canis Majoris ''. The Astronomical Journal. 121 ( 2 ) : 1111 -- 1125. Bibcode : 2001AJ... 121.1111 S. doi : 10.1086 / 318748. Jump up ^ Wehrse, R. ; Scholz, M. ; Baschek, B. ( June 1991 ). `` The parameters R and Teff in stellar models and observations ''. Astronomy and Astrophysics. 246 ( 2 ) : 374 -- 382. Bibcode : 1991A&A... 246... 374B. Further reading Kastner, Joel H. ; Weintraub, David A. ( 1998 ). `` Hubble Space Telescope Imaging of the Mass - losing Supergiant VY Canis Majoris ''. Astronomical Journal. 115 ( 4 ) : 1592 -- 1598. Bibcode : 1998AJ... 115.1592 K. doi : 10.1086 / 300297. External links Wikimedia Commons has media related to VY Canis Majoris. Astronomers Map a Hypergiant Star 's Massive Outbursts, HubbleSite NewsCenter, 2007 - 01 - 08 `` What is the Biggest Star in the Universe ? '', Fraser Cain, Universe Today, published 2008 - 04 - 06, updated 13 May 2013 Coordinates : 07 22 58.33, − 25 ° 46 ′ 03.17 '' Amos, Jonathan ( 27 November 2009 ). `` Herschel telescope ' fingerprints ' colossal star ''. BBC News. Retrieved 30 November 2009. The death throes of one of the biggest stars known to science have been spied by Europe 's Herschel space telescope. American Association of Variable Star Observers Remote Sensing Tutorial Page A-5 archive Preceded by VV Cephei A Largest known star 2007 -- 2012 Succeeded by NML Cygni < < < 5. VX Sagittarii 6 / 7. VY Canis Majoris / KY Cygni 8. AH Scorpii > > > The 10 largest stars by radius The Ten largest stars in solar radius The Ten largest stars 1st. UY Scuti 1,708 ± 192 2nd. WOH G64 1,540 3rd. RW Cephei 1,535 4th. Westerlund 1 - 26 1,530 -- 1,580 -- 2,544 5th. VX Sagittarii 1,520 ( 1,350 -- 1,940 ) 7th / 6th. KY Cygni 1,420 7th / 6th. VY Canis Majoris 1,420 8th. AH Scorpii 1,411 9th. VV Cephei A 1,400 ( 1,050 -- 1,800 ) 10th. HR 5171 1,315 ± 260 - 1,490 ± 540 For comparison Mu Cephei 1,260 ( 650 -- 1,420 ) NML Cygni 1,183 -- 2,775 Betelgeuse 1,180 KW Sagittarii 1,009 - 1,460 Antares 883 CW Leonis 826 V382 Carinae 747 TV Geminorum 620 - 710 Canis Major constellation Stars ( list ) Bayer α ( Sirius ) β ( Mirzam ) γ ( Muliphein ) δ ( Wezen ) ε ( Adhara ) ζ ( Furud ) η ( Aludra ) θ ι κ λ μ ν ν ν ξ ξ ο ο π σ τ ω Flamsteed 10 11 12 15 17 26 27 Variable Z SW UW ( 29 ) VY CX DZ EZ FN FR FS FV FW FY FZ GU GY GZ HN HP HQ HR HZ IL IP IY KM KX LS LZ MZ NO NR OS CX V350 V352 V415 HR 2242 2243 2244 2249 2254 2260 2266 2268 2271 2303 2305 2307 2309 2311 2318 2349 2359 2373 2379 2380 2397 2403 2415 2428 2437 2447 2448 2450 2455 2460 2493 2495 2498 2500 2522 2528 2535 2544 2565 2566 2576 2578 2595 2598 2607 2611 2614 2616 2621 2623 2625 2637 2664 2679 2686 2705 2708 2716 2720 2723 2730 2733 2743 2750 2755 2756 2758 2764 2766 2768 2774 2785 2786 2796 2812 2822 2823 2826 2831 2832 2834 2839 2841 2847 2859 HD 43197 44225 44379 44394 45184 45364 45420 46037 47012 47186 47579 56578 Other EUVE J0720 - 317 PSR B0628 - 28 RX J0720. 4 - 3125 WISE 0713 - 2917 WR 7 Star clusters Open Collinder 121 Messier 41 NGC 2204 NGC 2243 NGC 2345 NGC 2354 NGC 2358 NGC 2360 NGC 2362 NGC 2367 NGC 2374 NGC 2383 NGC 2384 Nebulae HII NGC 2359 NGC 2361 Reflection NGC 2296 NGC 2327 Planetary IC 2165 M 1 - 11 Galaxies NGC 2206 2207 2211 2212 2216 2217 2223 2227 2263 2267 2271 2272 2280 2283 2292 2293 2295 2318 2325 2382 Other Canis Major Overdensity ESO 428 - G14 IC 2163 PKS 0634 - 205 I Zw 36 Other SN 1999ec SN 2003H Retrieved from `` https://en.wikipedia.org/w/index.php?title=VY_Canis_Majoris&oldid=801247694 '' Categories : M - type hypergiants M - type supergiants Canis Major Objects with variable star designations Henry Draper Catalogue objects Durchmusterung objects Hipparcos objects Hidden categories : Use dmy dates from September 2012 Talk Contents About Wikipedia Aragonés Bân - lâm - gú Беларуская Български Català Čeština Dansk Deutsch Eesti Ελληνικά Español Euskara فارسی Français 한국어 हिन्दी Bahasa Indonesia Íslenska Italiano עברית ქართული Kurdî Lëtzebuergesch Lietuvių Magyar Македонски മലയാളം मराठी Nederlands 日本 語 Norsk Polski Português Română Русский Scots Simple English Slovenčina Slovenščina Српски / srpski Suomi Svenska Татарча / tatarça ไทย Türkçe Українська Tiếng Việt 文言 粵語 中文 Edit links This page was last edited on 18 September 2017, at 15 : 47. 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Question: what is the temperature of vy canis majoris
Answer: about 3,500 K