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Delta Canis Majoris

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"Wezen" redirects here. Not to be confused withWazn,a star in Columba.
δ Canis Majoris
Location of δ Canis Majoris (circled)
Observation data
EpochJ2000EquinoxJ2000
Constellation Canis Major
Right ascension 07h08m23.48608s[1]
Declination −26° 23′ 35.5474″[1]
Apparent magnitude(V) 1.824[2]
Characteristics
Spectral type F8 Ia[3]
U−Bcolor index +0.584[2]
B−Vcolor index +0.67[4][5]
Variable type ?[6]
Astrometry
Radial velocity(Rv)34.3 ± 0.9[7]km/s
Proper motion(μ)RA:–3.12[1]mas/yr
Dec.:+3.31[1]mas/yr
Parallax(π)2.03 ± 0.38mas[1]
Distanceapprox. 1,600ly
(approx. 490pc)
Absolute magnitude(MV)–5.97[4]
Details
Mass14.9[8]M☉
Radius188[9]R☉
Luminosity37,500[10]– 51,000[11]L☉
Surface gravity(logg)1.00[8]cgs
Temperature5,850[8]K
Metallicity[Fe/H]0.28[4]dex
Rotational velocity(vsini)13.4±1.9[5]km/s
Age12[8]Myr
Other designations
Wezen, Wesen, Wezea, Alwazn, Al Wazor,25Canis Majoris,CD−263916,FK5273,HD54605,HIP34444,HR2693,SAO173047.
Database references
SIMBADdata

Delta Canis Majoris(Latinisedfromδ Canis Majoris,abbreviatedDelta CMa,δ CMa), officially namedWezen/ˈwiːzən/,[12]is astarin theconstellationofCanis Major.It is a yellow-whiteF-typesupergiantwith anapparent magnitudeof +1.83. Since 1943, thespectrumof this star has served as one of the stable anchor points by which other stars are classified.[13]

Observation

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Delta Canis Majoris is the third-brightest star in the constellation afterSiriusandε Canis Majoris(Adhara), with anapparent magnitudeof +1.83, and is white or yellow-white in colour. Lying about 10 degrees south southeast of Sirius, it only rises to about 11 degrees above the horizon at the latitude of the United Kingdom.[14]The open clusterNGC 2354is located only 1.3 degrees east of Delta Canis Majoris.[15]As with the rest of Canis Major, Delta Canis Majoris is most visible in winter skies in thenorthern hemisphere,and summer skies in the southern. In Bayer's Uranometria, it is in the Great Dog's hind quarter.[16]

History and naming

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δ Canis Majoris(Latinised toDelta Canis Majoris) is the star'sBayer designation.

The traditional name,Wezen(alternativelyWesen,orWezea), is derived from the medieval Arabicوزنal-wazn,which means 'weight' in modernArabic.The name was for one of a pair of stars, the other beingHadar,which has now come to refer toBeta Centauri.It is unclear whether the pair of stars was originallyAlphaand Beta Centauri orAlphaandBeta Columbae.In any case, the name was somehow applied to both Delta Canis Majoris and Beta Columbae.[17]Richard Hinckley Allenmuses that the name alludes to the difficulty the star has rising above the horizon in the northern hemisphere.[16]AstronomerJim Kalerhas noted the aptness of the traditional name given the star's massive nature.[18]

In 2016, theInternational Astronomical Unionorganized aWorking Group on Star Names(WGSN)[19]to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[20]included a table of the first two batches of names approved by the WGSN; which includedWezenfor this star.

InChinese,Hồ thỉ(Hú Shǐ), meaningBow and Arrow,[21]refers to an asterism consisting of δ Canis Majoris,ε Canis Majoris,η Canis Majoris,κ Canis Majoris,ο Puppis,π Puppis,χ Puppis,c Puppisandk Puppis.Consequently, δ Canis Majoris itself is known asHồ thỉ nhất(Hú Shǐ yī,English:the First Star of Bow and Arrow.)[22]

In the catalogue of stars in theCalendarium of Al Achsasi Al Mouakket,this star was designatedThalath al Adzari(تالت ألعذاري-taalit al-aðārii), which was translated intoLatinasTertia Virginum,meaningthe third virgin.[23]This star, along withε Canis Majoris(Adhara),η Canis Majoris(Aludra) andο2Canis Majoris(Thanih al Adzari), wereAl ʽAdhārā(ألعذاري), the Virgins.[24][25]

Physical properties

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Artist's illustration of Wezen, a yellow supergiant 1,600 light-years away in the Canis Major constellation

Delta Canis Majoris is asupergiantofclassF8. Its surface temperature is around 5,818 K,[26]and it is 14 times more massive than the Sun.[8]Its absolute magnitude is −5.97,[4]and it lies around 1,600light-yearsaway. It is rotating at a speed of around 28 km/s, and hence may take a year to rotate fully. Only around 10 million years old, Delta Canis Majoris has stopped fusinghydrogenin its core. Its outer envelope is beginning to expand and cool, and in the next 100,000 years it will become a red supergiant as its core fuses heavier and heavier elements. Once it has anironcore, it will collapse and explode as asupernova.[18]

Theangular diameterof Wezen has been measured usinginterferometry,giving alimb-darkened diameterof3.633±0.026milliarcseconds.J Daviset al.(2007) used this angular diameter and calculated a physical radius of215±66R☉using aparallaxof1.82±0.56 milliarcsecondsmeasured by theHipparcosspecrcaft, which implies a distance of1800±550light-years.[26]Since then, the 2007 Hipparcos reduction refined the parallax to2.03±0.38 mas,corresponding a distance of about1600±300 ly(493parsecs).[1]This distance gives a smaller radius of 193R☉using the angular diameter.[27]Following the new distance, a 2017 study published a radius of 188R☉based on the stellar temperature and luminosity.[9]

If Delta Canis Majoris were as close to Earth as Sirius is, it would be as bright as a half-full moon.[28]

Modern legacy

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Delta Canis Majoris appears on theflag of Brazil,symbolising the state ofRoraima.[29]

References

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  1. ^abcdefvan Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction".Astronomy and Astrophysics.474(2): 653–664.arXiv:0708.1752.Bibcode:2007A&A...474..653V.doi:10.1051/0004-6361:20078357.S2CID18759600.
  2. ^abGutierrez-Moreno, Adelina; et al. (1966). "A System of photometric standards".Publ. Dept. Astron. Univ. Chile.1.Publicaciones Universidad de Chile, Department de Astronomy: 1–17.Bibcode:1966PDAUC...1....1G.
  3. ^Lyubimkov, Leonid S.; et al. (February 2010)."Accurate fundamental parameters for A-, F- and G-type Supergiants in the solar neighbourhood".Monthly Notices of the Royal Astronomical Society.402(2): 1369–1379.arXiv:0911.1335.Bibcode:2010MNRAS.402.1369L.doi:10.1111/j.1365-2966.2009.15979.x.S2CID119096173.
  4. ^abcdLuck, R. Earle (2014-06-01)."Parameters and Abundances in Luminous Stars".The Astronomical Journal.147(6): 137.Bibcode:2014AJ....147..137L.doi:10.1088/0004-6256/147/6/137.ISSN0004-6256.Delta Canis Majoris' database entryat VizieR.
  5. ^abAmmler-von Eiff, M.; Reiners, A. (2012-06-01)."New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars?".Astronomy and Astrophysics.542:A116.arXiv:1204.2459.Bibcode:2012A&A...542A.116A.doi:10.1051/0004-6361/201118724.ISSN0004-6361.Delta Canis Majoris' database entryatVizieR.
  6. ^Koen, Chris; Eyer, Laurent (2002)."New periodic variables from the Hipparcos epoch photometry".Monthly Notices of the Royal Astronomical Society.331(1): 45–59.arXiv:astro-ph/0112194.Bibcode:2002MNRAS.331...45K.doi:10.1046/j.1365-8711.2002.05150.x.ISSN0035-8711.S2CID10505995.
  7. ^Evans, D. S. (June 20–24, 1966). Batten, Alan Henry; Heard, John Frederick (eds.). "The Revision of the General Catalogue of Radial Velocities".Determination of Radial Velocities and Their Applications, Proceedings from IAU Symposium No. 30.30.University of Toronto: International Astronomical Union: 57.Bibcode:1967IAUS...30...57E.
  8. ^abcdeLyubimkov, Leonid S.; Lambert, David L.; Korotin, Sergey A.; Rachkovskaya, Tamara M.; Poklad, Dmitry B. (2015-02-01), "Carbon abundance and the N/C ratio in atmospheres of A-, F- and G-type supergiants and bright giants",Monthly Notices of the Royal Astronomical Society,446(4): 3447–3460,arXiv:1411.2722,Bibcode:2015MNRAS.446.3447L,doi:10.1093/mnras/stu2299,ISSN1365-2966
  9. ^abMcDonald, I.; Zijlstra, A. A.; Watson, R. A. (2017-10-01)."Fundamental parameters and infrared excesses of Tycho-Gaia stars".Monthly Notices of the Royal Astronomical Society.471(1): 770–791.arXiv:1706.02208.Bibcode:2017MNRAS.471..770M.doi:10.1093/mnras/stx1433.ISSN0035-8711.Wezen's database entryatVizieR.
  10. ^M., Hohle, M.; R., Neuhäuser; F., Schutz, B. (April 2010)."Masses and luminosities of O- and B-type stars and red supergiants".Astronomische Nachrichten.331(4): 349.arXiv:1003.2335.Bibcode:2010AN....331..349H.doi:10.1002/asna.200911355.ISSN0004-6337.{{cite journal}}:CS1 maint: multiple names: authors list (link)Delta Canis Majoris' database entry inVizieR.
  11. ^Arellano Ferro, A.; Giridhar, S.; Rojo Arellano, E. (April 2003). "A Revised Calibration of the MV-W(O I 7774) Relationship using Hipparcos Data: Its Application to Cepheids and Evolved Stars".Revista Mexicana de Astronomía y Astrofísica.39:3–15.arXiv:astro-ph/0210695.Bibcode:2003RMxAA..39....3A.
  12. ^"IAU Catalog of Star Names".Retrieved28 July2016.
  13. ^Garrison, R. F. (December 1993)."Anchor Points for the MK System of Spectral Classification".Bulletin of the American Astronomical Society.25:1319.Bibcode:1993AAS...183.1710G.Archived fromthe originalon 2019-06-25.Retrieved2012-02-04.
  14. ^Mobberly, Martin (2009).The Caldwell Objects and How to Observe Them.Springer. p. 136.ISBN978-1-4419-0325-9.
  15. ^"Canis Major".
  16. ^abAllen, R H(1963) [1899].Star Names: Their Lore and Meaning(rep.ed.).New York,NY:Dover PublicationsInc. p.130.ISBN0-486-21079-0.
  17. ^Kunitzsch, Paul; Smart, Tim (2006).A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations(2nd rev. ed.).Cambridge,MA:Sky Pub.p. 23.ISBN978-1-931559-44-7.
  18. ^abKaler, James B."Wezen".Stars website.University of Illinois.Retrieved28 May2010.
  19. ^"IAU Working Group on Star Names (WGSN)".Retrieved22 May2016.
  20. ^"Bulletin of the IAU Working Group on Star Names, No. 1"(PDF).Retrieved28 July2016.
  21. ^Hồ thỉ (Hú Shǐ) is westernized intoKoo She.R.H. Allen had opinion thatKoo Sherefers to the asterism includingδ Velorumandω Velorum.AEEA opinion is, δ Velorum is member ofThiên xã(Tiān Shè), meaningCelestial Earth God's Templeasterism and ω Velorum is not member of any asterisms. Thiên xã (Tiān Shè) is westernized intoTseen Sheand R.H.Allen used the termTseen Shefor Chinese name ofη Carinae.SeeRichard Hinckley Allen: Star Names — Their Lore and Meaning: Argo Navisand(in Chinese)AEEA (Activities of Exhibition and Education in Astronomy) thiên văn giáo dục tư tấn võng 2006 niên 7 nguyệt 17 nhật.
  22. ^(in Chinese)AEEA (Activities of Exhibition and Education in Astronomy) thiên văn giáo dục tư tấn võng 2006 niên 7 nguyệt 17 nhật
  23. ^Knobel, E. B. (June 1895)."Al Achsasi Al Mouakket, on a catalogue of stars in the Calendarium of Mohammad Al Achsasi Al Mouakket".Monthly Notices of the Royal Astronomical Society.55(8): 429–438.Bibcode:1895MNRAS..55..429K.doi:10.1093/mnras/55.8.429.
  24. ^Allen, R. H.(1963).Star Names: Their Lore and Meaning(Reprint ed.). New York: Dover Publications Inc. p.130.ISBN0-486-21079-0.Retrieved2010-12-12.
  25. ^ε CMaasAoul al AdzariorPrima Virginum(the first virgin),ο2CMaasThanih al AdzariorSecunda Virginum(the second virgin) and δ CMa asThalath al AdzariorTertia Virginum(the third virgin).η CMashould beRabah al AdzariorQuarta Virginum(the fourth virgin) consistently, but it was given by the nameAludra,meaning 'the virgin' (same meaning with Adhara (ε CMa) orAl ʽAdhārā)
  26. ^abDavis, J.; et al. (October 2007). "The Emergent Flux and Effective Temperature of δ Canis Majoris".Publications of the Astronomical Society of Australia.24(3): 151–158.arXiv:0709.3873.Bibcode:2007PASA...24..151D.doi:10.1071/AS07017.S2CID9095731.
  27. ^Lang, Kenneth R. (2006),Astrophysical formulae,Astronomy and astrophysics library, vol. 1 (3 ed.),Birkhäuser,ISBN978-3-540-29692-8.The radius (R*) is given by:
  28. ^Ridpath, Ian; Tirion, Will (2003).The Monthly Sky Guide.Cambridge University Press. p. 16.ISBN0-521-53306-6.
  29. ^"Astronomy of the Brazilian Flag".FOTW Flags Of The World website.
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