Alpha Ceti (α Ceti, abbreviated Alpha Cet, α Cet), officially named Menkar , is the second-brightest star in the constellation of

Cetus Cetus () is a constellation, sometimes called 'the whale' in English. The Cetus was a sea monster in Greek mythology which both Perseus and Heracles needed to slay. Cetus is in the region of the sky that contains other water-related constellat ...

. It is a cool luminous red giant about 250 light years away.

Nomenclature

''Alpha Ceti'' is the star's Bayer designation. It has the traditional name Menkar, deriving from the Arabic word منخر ''manħar'' "nostril" (of Cetus). 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 catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included ''Menkar'' for this star. This star, along with γ Cet (Kaffaljidhma), δ Cet, λ Cet (also Menkar), μ Cet, ξ¹ Cet and ξ² Cet were ''Al Kaff al Jidhmah'', "the Part of a Hand". In

Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation ** List of ethnic groups in China, people of ...

, (), meaning '' Circular Celestial Granary'', refers to an asterism consisting of α Ceti, κ¹ Ceti, λ Ceti, μ Ceti, ξ¹ Ceti, ξ² Ceti, ν Ceti, γ Ceti, δ Ceti, 75 Ceti, 70 Ceti, 63 Ceti and 66 Ceti. Consequently, the

Chinese name Chinese names or Chinese personal names are names used by individuals from Greater China and other parts of the Chinese-speaking world throughout East and Southeast Asia (ESEA). In addition, many names used in Japan, Korea and Vietnam are ofte ...

for α Ceti itself is (, en, the First Star of Circular Celestial Granary.)AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 11 日
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Structure

Despite having the Bayer designation α Ceti, at visual magnitude 2.54 this star is actually not the brightest star in the constellation Cetus. That honor goes instead to

Beta Ceti Beta Ceti (β Ceti, abbreviated Beta Cet, β Cet), officially named Diphda , is the brightest star in the constellation of Cetus. Although designated 'beta', it is actually brighter than the 'alpha' star in the constellation ( Alpha Ceti ...

at magnitude 2.04. Menkar is a red giant with a stellar classification of M1.5 IIIa. It has more than twice the mass of the Sun and, as a

giant star A giant star is a star with substantially larger radius and luminosity than a main-sequence (or ''dwarf'') star of the same surface temperature.Giant star, entry in ''Astronomy Encyclopedia'', ed. Patrick Moore, New York: Oxford University Press ...

has expanded to about 89 times the Sun's radius. The large area of the photosphere means that it is emitting about 1,455 times as much energy as the Sun, even though the effective temperature is only (compared to on the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

). The relatively low temperature gives Menkar the red hue of an M-type star. Menkar has evolved from the main sequence after exhausting the hydrogen at its core. It has also exhausted its core helium, becoming an asymptotic giant branch star, and will probably become a highly unstable star like

Mira Mira (), designation Omicron Ceti (ο Ceti, abbreviated Omicron Cet, ο Cet), is a red-giant star estimated to be 200–400 light-years from the Sun in the constellation Cetus. ο Ceti is a binary stellar system, consisting of a vari ...

before finally shedding its outer layers and forming a

planetary nebula A planetary nebula (PN, plural PNe) is a type of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives. The term "planetary nebula" is a misnomer because they are unrelate ...

, leaving a relatively large

white dwarf A white dwarf is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to the Sun's, while its volume is comparable to the Earth's. A white dwarf's faint luminosity comes ...

remnant. It has been observed to periodically vary in brightness, but only with an amplitude of about one hundredth of a magnitude.

Namesakes

''Menkar'' (AK-123) was a

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

Crater class cargo ship The ''Crater''-class cargo ship were converted EC2-S-C1 type, Liberty cargo ships, constructed by the United States Maritime Commission (USMC) for use by the US Navy during World War II. The designation 'EC2-S-C1': 'EC' for Emergency Cargo, '2' fo ...

named after the star.

References

External links

Assorted figures related to Alpha Ceti
{{DEFAULTSORT:Alpha Ceti M-type giants Asymptotic-giant-branch stars Cetus (constellation) Ceti, Alpha BD+03 0419 Ceti, 92 018884 014135 0911 Menkar

Nomenclature

Structure

Namesakes

See also

References

External links