Delta Canis Majoris
Template:Short description Template:Redirect-distinguish-text Template:Starbox begin Template:Starbox image Template:Starbox observe Template:Starbox character Template:Starbox astrometry Template:Starbox detail Template:Starbox catalog Template:Starbox reference Template:Starbox end Delta Canis Majoris (Latinised from δ Canis Majoris, abbreviated Delta CMa, δ CMa), officially named Wezen Template:IPAc-en,<ref name="IAU-CSN">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> is a star in the constellation of Canis Major. It is a yellow-white F-type supergiant with an apparent magnitude of +1.83. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.<ref name=baas25_1319/>
ObservationEdit
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.<ref>Template:Cite book</ref> The open cluster NGC 2354 is located only 1.3 degrees east of Delta Canis Majoris.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> 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.<ref name="allen"/>
History and namingEdit
δ Canis Majoris (Latinised to Delta Canis Majoris) is the star's Bayer designation.
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.<ref>Template:Cite book</ref> Richard Hinckley Allen muses that the name alludes to the difficulty the star has rising above the horizon in the northern hemisphere.<ref name="allen">Template:Cite book</ref> Astronomer Jim Kaler has noted the aptness of the traditional name given the star's massive nature.<ref name="Kaler">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)<ref name="WGSN">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016<ref name="WGSN1">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> included a table of the first two batches of names approved by the WGSN; which included Wezen for this star.
In Chinese, {{#invoke:Lang|lang}} ({{#invoke:Lang|lang}}), meaning Bow and Arrow,<ref>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 {{#invoke:Lang|lang}} ({{#invoke:Lang|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.</ref> 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 {{#invoke:Lang|lang}} ({{#invoke:Lang|lang}}, Template:Langx.)<ref>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</ref>
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.<ref>Template:Cite journal</ref> 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.<ref>Template:Cite book</ref><ref>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)</ref>
Physical propertiesEdit
Delta Canis Majoris is a supergiant of class F8. It is 14 to 15 times more massive than the Sun,<ref name=Neuhauser/> but around 190 times larger. It lies at a distance of 1,600 light-years from Earth and has a luminosity 35,000 times the Sun's luminosity.<ref name=tycho-gaia/> The effective temperature of 5,818 K,<ref name="PASA24_3_151"/> similar to the Sun's temperature of 5,772 K. 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 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. Once it has an iron core, it will collapse and explode as a supernova.<ref name="Kaler"/>
If Delta Canis Majoris were as close to Earth as Sirius is, it would be as bright as a half-full moon.<ref>Template:Cite book</ref>
Modern legacyEdit
Delta Canis Majoris appears on the flag of Brazil, symbolising the state of Roraima.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>