Alpha Crateris is an orange-hued star in the southern constellation of Crater. It has the proper name Alkes, pronounced ; Alpha Crateris is its Bayer designation. This is a cool giant star that is visible to the naked eye with an apparent visual magnitude of 4.07. Based on parallax measurements, it is located at a distance of approximately from the Earth. It is drifting further away with a line of sight velocity component of 47.5 km/s.
Nomenclature α Crateris (Latinised to Alpha Crateris) is the star's Bayer designation, abbreviated Alpha Crt or α Crt.
It bore the traditional name Alkes, from the Arabic الكاس alkās or الكأس alka's "the cup". In the catalogue of stars in the Calendarium of Al Achsasi al Mouakket, this star was designated Aoul al Batjna (أول ألباطیة awwal al-bāṭiya), which was translated into Latin as Prima Crateris, meaning "first [star] of the Cup". In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars. The WGSN approved the name Alkes for this star on 12 September 2016 and it is now so included in the List of IAU-approved Star Names.
In Chinese, (), meaning Wings (asterism), refers to an asterism consisting of Alpha Crateris, Gamma Crateris, Zeta Crateris, Lambda Crateris, Nu Hydrae, Eta Crateris, Delta Crateris, Iota Crateris, Kappa Crateris, Epsilon Crateris, HD 95808, HD 93833, Theta Crateris, HD 102574, HD 100219, Beta Crateris, HD 99922, HD 100307, HD 96819, Chi1 Hydrae, HD 102620 and HD 103462. 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, . Consequently, Alpha Crateris itself is known as (, ). 香港太空館 - 研究資源 - 亮星中英對照表 , Hong Kong Space Museum. Accessed on line November 23, 2010.
Properties Alpha Crateris is a giant star with a stellar classification of K1III, which suggests it has exhausted the supply of hydrogen at its core and evolved away from the main sequence. It is thought to be a horizontal branch star, meaning it is fusing helium in its core after a helium flash. Cool horizontal branch stars are often called red clump giants as they form a noticeable grouping near the hot edge of the red giant branch in the H–R diagrams of clusters with near-solar metallicity. On this basis it is calculated to have a mass of , a luminosity of , and an age around two billion years. Its effective temperature is 4691 K. Or it might be a red-giant branch star, still fusing hydrogen in a shell around an inert helium core, in which case it would be slightly less massive, older, cooler, larger, and more luminous.
Namesake was a United States Navy named after the star.
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