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

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 ...

of Cetus. It is a cool luminous

red giant A red giant is a luminous giant star of low or intermediate mass (roughly 0.3–8 solar masses ()) in a late phase of stellar evolution. The outer atmosphere is inflated and tenuous, making the radius large and the surface temperature around or ...

about 250

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 away.

Nomenclature

''Alpha Ceti'' 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 has the traditional name Menkar, deriving from the Arabic word منخر ''manħar'' "nostril" (of Cetus). In 2016, the International Astronomical Union organized a Working Group on Star Names (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 va ...

, (), meaning '' Circular Celestial Granary'', refers to an asterism consisting of α Ceti, κ¹ Ceti, λ Ceti, μ Ceti, ξ¹ Ceti, ξ² Ceti,

ν Ceti ν Ceti, Latinized as Nu Ceti, is a binary star system in the equatorial constellation of Cetus. It is visible to the naked eye as a faint point of light with a combined apparent visual magnitude of 4.86. The system is located approxi ...

γ Ceti Gamma Ceti (γ Ceti, abbreviated Gamma Cet, γ Cet) is a triple star system in the equatorial constellation of Cetus. It has a combined apparent visual magnitude of 3.47. Based upon parallax measurements, this star is located at a dista ...

δ Ceti Delta Ceti, Latinized from δ Ceti, is a single, blue-white hued star in the equatorial constellation of Cetus. The star's apparent visual magnitude of +4.06 means it is near to the cusp of the faintest third of the stars that are visi ...

75 Ceti 75 Ceti is a single star in the equatorial constellation of Cetus with at least one planet. It is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of +5.36. The star is located 271 light years dis ...

70 Ceti 7 (seven) is the natural number following 6 and preceding 8. It is the only prime number preceding a cube (algebra), cube. As an early prime number in the series of positive integers, the number seven has greatly symbolic associations in religion ...

63 Ceti 63 Ceti is a star in the constellation of Cetus, located just over a degree south of the celestial equator. With an apparent magnitude of about 5.9, the star is barely visible to the naked eye (see Bortle scale) as a dim, orange-hued po ...

and

66 Ceti 66 may refer to: * 66 (number) * One of the years 66 BC, AD 66, 1966, 2066 * "66" (song), a song by Lil Yachty featuring Trippie Redd *66, a song by The Afghan Whigs, from the album 1965 *Sixty-Six (card game), a German card game * ''Sixty Six ...

. Consequently, the Chinese name 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 at magnitude 2.04. Menkar is a

with a

stellar classification In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grati ...

of M1.5 IIIa. It has more than twice the

mass of the Sun The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass ...

and, as a giant star has expanded to about 89 times the Sun's radius. The large area of the

photosphere The photosphere is a star's outer shell from which light is radiated. The term itself is derived from Ancient Greek roots, φῶς, φωτός/''phos, photos'' meaning "light" and σφαῖρα/''sphaira'' meaning "sphere", in reference to it ...

means that it is emitting about 1,455 times as much energy as the Sun, even though the

effective temperature The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature ...

is only (compared to on the Sun). The relatively low temperature gives Menkar the red hue of an M-type star. Menkar has evolved from the

main sequence In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Her ...

after exhausting the hydrogen at its core. It has also exhausted its core helium, becoming an

asymptotic giant branch star The asymptotic giant branch (AGB) is a region of the Hertzsprung–Russell diagram populated by evolved cool luminous stars. This is a period of stellar evolution undertaken by all low- to intermediate-mass stars (about 0.5 to 8 solar masses) late ...

, and will probably become a highly unstable star like Mira before finally shedding its outer layers and forming a planetary nebula, leaving a relatively large white dwarf 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 Crater class cargo ship 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 Alpha Ceti (α Ceti, abbreviated Alpha Cet, α Cet), officially named Menkar , is the second-brightest star in the constellation of Cetus. It is a cool luminous red giant about 250 light years away. Nomenclature ''Alpha Ceti'' is the ...

Nomenclature

Structure

Namesakes

See also

References

External links