Delta Canis Majoris

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δ Canis Majoris
Template:Location mark
Location of δ Canis Majoris (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Canis Major
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) 1.824[2]
Characteristics
Spectral type F8 Ia[3]
U−B Template:Engvar +0.584[2]
B−V Template:Engvar +0.67[4][5]
Variable type Suspected[6]
Astrometry
Radial velocity (Rv)Script error: No such module "val".[7] km/s
Proper motion (μ) RA: −3.12[1] mas/yr[1]
Dec.: +3.31 mas/yr[1]
Parallax (π)2.03±0.38 mas[1]
Distanceapprox. Template:Rnd ly
(approx. Template:Rnd pc)[1]
Absolute magnitude (MV)Script error: No such module "val".[8]
Details
Mass14–15[8] Template:Solar mass
Radius188[9] Template:Solar radius
LuminosityScript error: No such module "val".[9] Template:Solar luminosity
Surface gravity (log g)Script error: No such module "val".[3] cgs
TemperatureScript error: No such module "val".[10] K
Metallicity [Fe/H]0.28[4] dex
Rotational velocity (v sin i)Script error: No such module "val".[5] km/s
Age12[3] Myr
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Template:Odlist[11]
Database references
SIMBADdata

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Delta Canis Majoris is a supergiant star in the constellation of Canis Major. It is formally named Wezen (Template:IPAc-en);[12] Delta Canis Majoris is its Bayer designation. At an apparent magnitude of +1.83, it is the third-brightest star in the constellation. Based on parallax measurements, it is located at a distance of approximately 1,600 light years. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[13]

Observation

Delta Canis Majoris is the third-brightest star in the constellation after Sirius and ε Canis Majoris (Adhara), with an apparent magnitude of +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 cluster NGC 2354 is 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 the northern hemisphere, and summer skies in the southern. In Bayer's Uranometria, it is in the Great Dog's hind quarter.[16]

History and naming

δ Canis Majoris (Latinised to Delta Canis Majoris) is the star's Bayer designation, abbreviated δ CMa or Delta CMa.

The traditional name, Wezen (alternatively Wesen, or Wezea), is derived from the medieval Arabic وزن al-wazn, which means 'weight' in modern Arabic. The name was for one of a pair of stars, the other being Hadar, which has now come to refer to Beta Centauri. It is unclear whether the pair of stars was originally Alpha and Beta Centauri or Alpha and Beta Columbae. In any case, the name was somehow applied to both Delta Canis Majoris and Beta Columbae.[17] Richard Hinckley Allen muses that the name alludes to the difficulty the star has rising above the horizon in the northern hemisphere.[16] Astronomer Jim Kaler has noted the aptness of the traditional name given the star's massive nature.[18]

In 2016, the International Astronomical Union organized a Working 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 included Wezen for this star.

In Chinese, Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Bow 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 Puppis and k Puppis. Consequently, δ Canis Majoris itself is known as Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx.)[22]

In the catalogue of stars in the Calendarium of Al Achsasi Al Mouakket, this star was designated Thalath al Adzari (تالت ألعذاري - taalit al-aðārii), which was translated into Latin as Tertia Virginum, meaning the third virgin.[23] This star, along with ε Canis Majoris (Adhara), η Canis Majoris (Aludra) and ο2 Canis Majoris (Thanih al Adzari), were Al ʽAdhārā (ألعذاري), the Virgins.[24][25]

Physical properties

File:Wezen.jpg
Artist's illustration of Wezen

Delta Canis Majoris is a supergiant star with a stellar classification of F8 Ia.[3] It is 14 to 15 times more massive than the Sun,[8] but around 190 times larger. It lies at a distance of 1,600 light-years from Earth and has 35,000 times the Sun's luminosity.[9] The effective temperature of 5,818 K[10] is similar to the Sun's temperature of 5,772 K. It is rotating with an equatorial speed of around 28 km/s, and hence may take a year to rotate fully. Only around 12 million years old, Delta Canis Majoris has stopped fusing hydrogen in 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. After it develops an inert iron core, it will collapse and explode as a supernova.[18]

If Delta Canis Majoris were as close to Earth as Sirius is, it would be as bright as a half-full moon.[26]

Modern legacy

Delta Canis Majoris appears on the flag of Brazil, symbolising the state of Roraima.[27]

References

  1. ↑ a b c d e f Script error: No such module "Citation/CS1".
  2. ↑ a b Script error: No such module "Citation/CS1".
  3. ↑ a b c d Script error: No such module "Citation/CS1".
  4. ↑ a b Script error: No such module "Citation/CS1". Delta Canis Majoris' database entry at VizieR.
  5. ↑ a b Script error: No such module "Citation/CS1". Delta Canis Majoris' database entry at VizieR.
  6. ↑ Script error: No such module "Citation/CS1".
  7. ↑ Script error: No such module "Citation/CS1".
  8. ↑ a b c Script error: No such module "Citation/CS1".
  9. ↑ a b c Script error: No such module "Citation/CS1". Wezen's database entry at VizieR.
  10. ↑ a b Script error: No such module "Citation/CS1".
  11. ↑ Template:Cite simbad
  12. ↑ Script error: No such module "citation/CS1".
  13. ↑ Script error: No such module "Citation/CS1".
  14. ↑ Script error: No such module "citation/CS1".
  15. ↑ Script error: No such module "citation/CS1".
  16. ↑ a b Script error: No such module "citation/CS1".
  17. ↑ Script error: No such module "citation/CS1".
  18. ↑ a b Script error: No such module "citation/CS1".
  19. ↑ Script error: No such module "citation/CS1".
  20. ↑ Script error: No such module "citation/CS1".
  21. ↑ 弧矢 (Hú Shǐ) is westernized into Koo She. R.H. Allen had opinion that Koo She refers to the asterism including δ Velorum and ω Velorum. AEEA opinion is, δ Velorum is member of Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Celestial Earth God's Temple asterism and ω Velorum is not member of any asterisms. 天社 (Tiān Shè) is westernized into Tseen She and R.H.Allen used the term Tseen She for Chinese name of η Carinae. See Richard Hinckley Allen: Star Names — Their Lore and Meaning: Argo Navis and Template:In lang AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 17 日 Template:Webarchive.
  22. ↑ Template:In lang AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 17 日 Template:Webarchive
  23. ↑ Script error: No such module "Citation/CS1".
  24. ↑ Script error: No such module "citation/CS1".
  25. ↑ ε CMa as Aoul al Adzari or Prima Virginum (the first virgin), ο2 CMa as Thanih al Adzari or Secunda Virginum (the second virgin) and δ CMa as Thalath al Adzari or Tertia Virginum (the third virgin). η CMa should be Rabah al Adzari or Quarta Virginum (the fourth virgin) consistently, but it was given by the name Aludra, meaning 'the virgin' (same meaning with Adhara (ε CMa) or Al ʽAdhārā)
  26. ↑ Script error: No such module "citation/CS1".
  27. ↑ Script error: No such module "citation/CS1".

Template:Stars of Canis Major Template:Authority control

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