Alpha Capricorni

Alpha Capricorni (α Capricorni, abbreviated Alpha Cap, α Cap) is an optical double star in the constellation of Capricornus. The two physically-unrelated components are designated α¹ Capricorni and α² Capricorni (also named Algedi^[1]).

They are separated by 0.11° on the sky, and resolvable with the naked eye, similar to Mizar and Alcor. α¹ Capricorni is fainter (apparent magnitude 4.27) than α² Capricorni (apparent magnitude 3.58).

Nomenclature

α Capricorni (Latinised to Alpha Capricorni) is the system's Bayer designation; α¹ and α² Capricorni, those of the two components.

Alpha Capricorni bore the traditional names Algedi, Algiedi, Al Giedi or Giedi, derived from the Arabic الجدي al-jady "the billy goat" or "kid". It also refers to the entire constellation of Capricornus. Giedi is sometimes also associated with Beta Capricorni. α¹ and α² Capricorni were also called Prima Giedi and Secunda Giedi, respectively. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)^[2] to catalogue and standardize proper names for stars. The WGSN approved the name Algedi for α² Capricorni on 21 August 2016 and it is now so entered in the IAU Catalog of Star Names.^[1]

Alpha Capricorni is known as 牛宿二 (the Second Star of the Ox) in Chinese.

References

Kaler, Jim (2005). "Algedi". Retrieved July 27, 2005.

External links

• Alpha Capricorni on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

Coordinates: 20^h 18^m 03.3^s, −12° 32′ 41″