Delta Canis Majoris
{{short description|Star in the constellation Canis Major}}
{{Redirect-distinguish-text|Wezen|Wazn, a star in Columba}}
{{Starbox begin
| name=δ Canis Majoris
}}
{{Starbox image
| image=
{{Location mark
|image=Canis Major constellation map.svg|alt=|float=center|width=240
|label=|position=right
|mark=Red circle.svg|mark_width=12|mark_link=δ CMa
|x=192|y=740
}}
|caption=Location of δ Canis Majoris (circled)
}}
{{Starbox observe
| epoch = J2000
| dec = {{DEC|−26|23|35.5474}}
| constell = Canis Major
}}
{{Starbox character
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{{Starbox astrometry
| radial_v = {{nowrap|34.3 ± 0.9}}
| parallax = 2.03
| p_error = 0.38
| absmag_v = {{val|-6.77|0.41}}
}}
{{Starbox detail
| luminosity= {{val|34600|6600|fmt=commas}}
| temperature = {{val|5818|53|fmt=commas}}
| rotational_velocity={{val|13.4|1.9}}
}}
{{Starbox catalog
| names=Wezen, Wesen, Wezea, Alwazn, Al Wazor, 25 Canis Majoris, CD−26°3916, FK5 273, HD 54605, HIP 34444, HR 2693, SAO 173047.
}}
{{Starbox reference
|Simbad=Delta+CMa
}}
{{Starbox end
}}
Delta Canis Majoris (Latinised from δ Canis Majoris, abbreviated Delta CMa, δ CMa), officially named Wezen {{IPAc-en|'|w|iː|z|ən}},{{cite web | url=http://www.pas.rochester.edu/~emamajek/WGSN/IAU-CSN.txt | title=IAU Catalog of Star Names |access-date=28 July 2016}} 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.
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.{{cite book|last1=Mobberly|first1=Martin|title=The Caldwell Objects and How to Observe Them|url=https://books.google.com/books?id=amPrWoOWgHcC&pg=PA136|year=2009|publisher=Springer|isbn=978-1-4419-0325-9|page=136}} The open cluster NGC 2354 is located only 1.3 degrees east of Delta Canis Majoris.{{cite web |url=https://www.angelfire.com/ky/astronomers/Canis.html |title = Canis Major}} 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.
History and naming
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.{{cite book |last1= Kunitzsch|first1=Paul|last2=Smart|first2=Tim|year = 2006|title = A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations |edition = 2nd rev. |publisher = Sky Pub |location = Cambridge, MA |isbn = 978-1-931559-44-7 |page = 23}} Richard Hinckley Allen muses that the name alludes to the difficulty the star has rising above the horizon in the northern hemisphere.{{cite book |last1 = Allen |first1 = R H |year = 1963 |orig-year = 1899 |title = Star Names: Their Lore and Meaning |edition = rep. |publisher = Dover Publications Inc. |location = New York, NY |isbn = 0-486-21079-0 |page = [https://archive.org/details/starnamestheirlo00alle/page/130 130] |author-link = Richard Hinckley Allen }} Astronomer Jim Kaler has noted the aptness of the traditional name given the star's massive nature.{{cite web|url=http://stars.astro.illinois.edu/sow/wezen.html|title=Wezen|last1=Kaler|first1=James B.|work=Stars website|publisher=University of Illinois|access-date=28 May 2010}}
In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN){{cite web | url=https://www.iau.org/science/scientific_bodies/working_groups/280/ | title=IAU Working Group on Star Names (WGSN)|access-date=22 May 2016}} to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016{{cite web | url=http://www.pas.rochester.edu/~emamajek/WGSN/WGSN_bulletin1.pdf | title=Bulletin of the IAU Working Group on Star Names, No. 1 |access-date=28 July 2016}} included a table of the first two batches of names approved by the WGSN; which included Wezen for this star.
In Chinese, {{lang|zh|弧矢}} ({{lang|zh-Latn|Hú Shǐ}}), meaning Bow and Arrow,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 {{lang|zh|天社}} ({{lang|zh-Latn|Tiān Shè}}), 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 [https://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Argo_Navis*.html Richard Hinckley Allen: Star Names — Their Lore and Meaning: Argo Navis] and {{in lang|zh}} [http://aeea.nmns.edu.tw/2006/0607/ap060717.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 17 日] {{Webarchive|url=https://web.archive.org/web/20120204114243/http://aeea.nmns.edu.tw/2006/0607/ap060717.html |date=2012-02-04 }}. 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 {{lang|zh|弧矢一}} ({{lang|zh-Latn|Hú Shǐ yī}}, {{langx|en|the First Star of Bow and Arrow}}.){{in lang|zh}} [http://aeea.nmns.edu.tw/2006/0607/ap060717.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 17 日] {{Webarchive|url=https://web.archive.org/web/20120204114243/http://aeea.nmns.edu.tw/2006/0607/ap060717.html |date=2012-02-04 }}
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.{{cite journal | last1=Knobel | first1=E. B. | title=Al Achsasi Al Mouakket, on a catalogue of stars in the Calendarium of Mohammad Al Achsasi Al Mouakket | journal=Monthly Notices of the Royal Astronomical Society | volume=55 | issue=8 | pages=429–438 |date=June 1895 | bibcode=1895MNRAS..55..429K | doi=10.1093/mnras/55.8.429| doi-access= free}} 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.{{cite book | last1=Allen | first1=R. H. | year=1963 | author-link=Richard Hinckley Allen | title=Star Names: Their Lore and Meaning | url=https://archive.org/details/starnamestheirlo00alle/page/130 | access-date=2010-12-12 | edition=Reprint | publisher=Dover Publications Inc | location=New York | isbn=0-486-21079-0 | page=[https://archive.org/details/starnamestheirlo00alle/page/130 130] | url-access=registration }}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)
Physical properties
Delta Canis Majoris is a supergiant of class F8. It is 14 to 15 times more massive than the Sun, 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. The effective temperature of 5,818 K, 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.
If Delta Canis Majoris were as close to Earth as Sirius is, it would be as bright as a half-full moon.{{cite book|last1=Ridpath|first1=Ian|last2=Tirion|first2=Will|title=The Monthly Sky Guide|url=https://books.google.com/books?id=UFQIutJ8GSsC&pg=PA15|year=2003|publisher=Cambridge University Press|isbn=0-521-53306-6|page=16}}
Modern legacy
Delta Canis Majoris appears on the flag of Brazil, symbolising the state of Roraima.{{cite web
|title=Astronomy of the Brazilian Flag
|url=https://flagspot.net/flags/br_astro.html
|publisher=FOTW Flags Of The World website
}}
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References
{{reflist|refs=
{{Cite journal |last1=McDonald |first1=I. |last2=Zijlstra |first2=A. A. |last3=Watson |first3=R. A. |date=2017-10-01 |title=Fundamental parameters and infrared excesses of Tycho-Gaia stars |bibcode=2017MNRAS.471..770M |journal=Monthly Notices of the Royal Astronomical Society |volume=471 |issue=1 |pages=770–791 |doi=10.1093/mnras/stx1433 |doi-access=free |issn=0035-8711|arxiv=1706.02208 }} [https://vizier.cds.unistra.fr/viz-bin/VizieR?-source=J/MNRAS/471/770&RAJ2000=107.097851 Wezen's database entry] at VizieR.
{{Cite journal| last1 = Davis | first1 = J.
| last2 = Booth | first2 = A. J.
| last3 = Ireland | first3 = M. J.
| last4 = Jacob | first4 = A. P.
| last5 = North | first5 = J. R.
| last6 = Owens | first6 = S. M.
| last7 = Robertson | first7 = J. G.
| last8 = Tango | first8 = W. J.
| last9 = Tuthill | first9 = P. G.
| display-authors = 1
| title = The Emergent Flux and Effective Temperature of δ Canis Majoris
| journal = Publications of the Astronomical Society of Australia
| volume = 24
| issue = 3
| pages = 151–158
|date=October 2007
| doi = 10.1071/AS07017
| bibcode = 2007PASA...24..151D
| arxiv = 0709.3873
| s2cid = 9095731
}}
{{Cite journal |last1=Ammler-von Eiff |first1=M. |last2=Reiners |first2=A. |date=2012-06-01 |title=New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars? |journal=Astronomy and Astrophysics |volume=542 |pages=A116 |doi=10.1051/0004-6361/201118724 |arxiv=1204.2459 |bibcode=2012A&A...542A.116A |issn=0004-6361}} [https://vizier.cds.unistra.fr/viz-bin/VizieR?-source=J/A%2BA/542/A116&Name=HD%2054605 Delta Canis Majoris' database entry] at VizieR.
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{{Stars of Canis Major}}
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{{DEFAULTSORT:Delta Canis Majoris}}