Alpha Crateris (α Crateris, abbreviated Alpha Crt, α Crt), officially named Alkes , is a

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Crater Crater may refer to: Landforms *Impact crater, a depression caused by two celestial bodies impacting each other, such as a meteorite hitting a planet *Explosion crater, a hole formed in the ground produced by an explosion near or below the surfac ...

. It is a cool

giant star A giant star is a star with substantially larger radius and luminosity than a main sequence, main-sequence (or ''dwarf'') star of the same effective temperature, surface temperature.Giant star, entry in ''Astronomy Encyclopedia'', ed. Patrick Moo ...

about away.

Nomenclature

''α Crateris'' ( Latinised to ''Alpha Crateris'') is the star's

Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek or Latin letter followed by the genitive form of its parent constellation's Latin name. The original list of Bayer designations contained 1,564 stars. ...

. It bore the traditional name ''Alkes'', from the

Arabic Arabic (, ' ; , ' or ) is a Semitic languages, Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C ...

الكاس ''alkās'' or الكأس ''alka's'' "the cup". In the catalogue of stars in the ''Calendarium'' of

Al Achsasi al Mouakket Muḥammad al-Akhṣāṣī al-Muwaqqit ( ar, محمد الاخصاصي الموقت) was an Egyptian astronomer whose and catalogue of stars, ('Pearls of brilliance upon the solar operations'), was written at Cairo about 1650. Al-Akhsasi was a s ...

, this star was designated ''Aoul al Batjna'' (أول ألباطیة ''awwal al-bāṭiya''), which was translated into

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

as ''Prima Crateris'', meaning "first

tar Tar is a dark brown or black viscous liquid of hydrocarbons and free carbon, obtained from a wide variety of organic materials through destructive distillation. Tar can be produced from coal, wood, petroleum, or peat. "a dark brown or black bit ...

of the Cup". In 2016, the

International Astronomical Union The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...

organized a

Working Group on Star Names The International Astronomical Union (IAU) established a Working Group on Star Names (WGSN) in May 2016 to catalog and standardize proper names for stars for the international astronomical community. It operates under Division C – Education ...

(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 A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expresse ...

(asterism)'', refers to an asterism consisting of Alpha Crateris,

Gamma Crateris Gamma Crateris is a binary star system, divisible with a small amateur telescope, and located at the center of the southern constellation of Crater. It is visible to the naked eye with an apparent visual magnitude of 4.06. With an annual ...

Zeta Crateris Zeta Crateris (ζ Crateris) is a probable binary star system in the southern constellation of Crater. Zeta Crateris appears to be about half-way between Epsilon Corvi to the southeast and Beta Crateris to the northwest, and marks the ...

Lambda Crateris Lambda Crateris, Latinized from λ Crateris, is the Bayer designation for a suspected binary star system in the southern constellation of Crater. With an annual parallax shift of 23.32 milliarcsecond as observed from Earth, it i ...

Nu Hydrae Nu Hydrae, Latinized from ν Hydrae, is an orange-hued star in the constellation Hydra, near the border with the neighboring constellation of Crater. It has an apparent visual magnitude of 3.115, which is bright enough to be seen with t ...

Eta Crateris Eta Crateris, Latinized from η Crateris, is a solitary star in the southern constellation of Crater. It marks the lip of the tilted bowl on the left side in the constellation. Eta Crateris lies in the sky NE of Zeta Crateris and NN ...

Delta Crateris Delta Crateris (δ Crt, δ Crateris; traditional name: Labrum) is a solitary star in the southern constellation of Crater. With an apparent visual magnitude of 3.56, it is the brightest star in this rather dim constellation. It has an a ...

Iota Crateris Iota Crateris (ι Crateris) is the Bayer designation for a binary star system in the southern constellation of Crater. It is faintly visible to the naked eye with an apparent visual magnitude of 5.48. According to the Bortle scale, th ...

Kappa Crateris Kappa Crateris (κ Crateris) is the Bayer designation for a star in the southern constellation of Crater. It has an apparent visual magnitude of 5.94, which, according to the Bortle scale, can be seen with the naked eye under dark ...

Epsilon Crateris Epsilon Crateris (ε Crateris) is a solitary star in the southern constellation of Crater. Visible to the naked eye, it has an apparent visual magnitude of 4.84. It is located in the sky above Beta Crateris, and slightly to the left, or e ...

HD 95808 HD 95808 is a double star in the constellation of Crater. Its apparent magnitude is 5.50, but interstellar dust makes it appear 0.11 magnitudes dimmer than it should be. It is located some 340 light-years (104 parsecs) away, based on parall ...

, HD 93833,

Theta Crateris Theta Crateris (θ Crateris) is a solitary star in the southern constellation of Crater. It is a photometric-standard star that is faintly visible to the naked eye with an apparent visual magnitude of 4.70. With an annual parallax shift o ...

, HD 102574, HD 100219,

Beta Crateris Beta Crateris, Latinized from β Crateris, is a binary star system in the southern constellation of Crater. It is visible to the naked eye with an apparent visual magnitude of 4.46. Based upon an annual parallax shift of 9.59 mas a ...

, HD 99922, HD 100307, HD 96819, Chi¹ Hydrae, HD 102620 and HD 103462. Consequently, Alpha Crateris itself is known as (, en, the First Star of Wings).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.

Namesake

was a United States Navy named after the star.

Properties

Alpha Crateris is an orange giant of spectral type K1III. It has an

apparent magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's li ...

of 4.07, and is 174

light-year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

s from Earth. It is thought to be a

horizontal branch The horizontal branch (HB) is a stage of stellar evolution that immediately follows the red-giant branch in stars whose masses are similar to the Sun's. Horizontal-branch stars are powered by helium fusion in the core (via the triple-alpha process) ...

star, meaning it is fusing helium in its core after a

helium flash A helium flash is a very brief thermal runaway nuclear fusion of large quantities of helium into carbon through the triple-alpha process in the core of low mass stars (between 0.8 solar masses () and 2.0 ) during their red giant phase (the Sun is ...

. Cool horizontal branch stars are often called

red clump Red is the color at the long wavelength end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–740 nanometres. It is a primary color in the RGB color model and a secondary ...

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 surface temperature is 4691 K. Or it might be a

red-giant branch The red-giant branch (RGB), sometimes called the first giant branch, is the portion of the giant branch before helium ignition occurs in the course of stellar evolution. It is a stage that follows the main sequence for low- to intermediate-mass sta ...

star, still fusing hydrogen in a shell around an insert helium core, in which case it would be slightly less massive, older, cooler, larger, and more luminous.

References

{{DEFAULTSORT:Alpha Crateris Crater (constellation) Crateris, Alpha Crateris, 07 095272 053740 K-type giants

Alkes Alpha Crateris (α Crateris, abbreviated Alpha Crt, α Crt), officially named Alkes , is a star in the constellation of Crater. It is a cool giant star about away. Nomenclature ''α Crateris'' ( Latinised to ''Alpha Crateris'') is t ...

4287 Durchmusterung objects Horizontal-branch stars