Alpha Ceti

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α Ceti
Template:Location mark
Location of α Ceti (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Cetus
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) 2.53[2]
Characteristics
Evolutionary stage AGB[3]
Spectral type M1.5 IIIa[4]
U−B Template:Engvar +1.93[2]
B−V Template:Engvar +1.64[2]
Astrometry
Radial velocity (Rv)Template:Val[5] km/s
Proper motion (μ) RA: Template:Val[1] mas/yr
Dec.: Template:Val[1] mas/yr
Parallax (π)13.09±0.44 mas[1]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute bolometric
magnitude (Mbol)		Template:Val[4]
Details
MassTemplate:Val;[6] 1.465–1.933[7] Template:Solar mass
RadiusTemplate:Val[7] Template:Solar radius
LuminosityTemplate:Val[7] Template:Solar luminosity
Surface gravity (log g)Template:Val[7] cgs
TemperatureTemplate:Val[7] K
Metallicity [Fe/H]Template:Val[7] dex
Rotational velocity (v sin i)6.9[8] km/s
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Menkar, 92 Ceti, HR 911, BD+03°419, HD 18884, SAO 110920, FK5 107, HIP 14135
Database references
SIMBADdata

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Alpha Ceti (α Ceti, abbreviated Alpha Cet, α Cet), officially named Menkar Template:IPAc-en,[9][10] is the second-brightest star in the constellation of Cetus. It is a cool luminous red giant estimated to be about 250 light years away based on parallax.

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 organized a Working Group on Star Names (WGSN)[11] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[12] 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".[13]

In Chinese, Script error: No such module "Lang". (Script error: No such module "Lang".), 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 for α Ceti itself is Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx.)[14]

Characteristics

File:AlphaCetLightCurve.png
A light curve for Alpha Ceti, plotted from Hipparcos data,[15] folded with the period derived by Koen and Eyer (2002)[16]

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 red giant with a stellar classification of M1.5 IIIa.[4] It has more than twice the mass of the Sun[6] and, as a giant star, has expanded to about 100 times the Sun's radius.[7] The large area of the photosphere means that it is emitting about 1,765 times as much energy as the Sun, even though the effective temperature is only Template:Val (compared to Template:Val on the Sun).[7] The relatively low temperature gives Menkar the red hue of an M-type star.[17]

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,[3] 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.[18] It has been observed to periodically vary in brightness, but only with an amplitude of about one hundredth of a magnitude.[16]

Namesakes

Menkar (AK-123) was a United States Navy Crater class cargo ship named after the star.

References

Template:Reflist

External links

Template:Sky

Template:Stars of Cetus

  1. ↑ a b c d e Cite error: Invalid <ref> tag; no text was provided for refs named aaa474_2_653
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  3. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named eggen
  4. ↑ a b c Cite error: Invalid <ref> tag; no text was provided for refs named aaa489_3_1271
  5. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named aaa430_165
  6. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named aaa460_3_855
  7. ↑ a b c d e f g h Cite error: Invalid <ref> tag; no text was provided for refs named Soubiran2024
  8. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named aj135_1_209
  9. ↑ Script error: No such module "citation/CS1".
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  11. ↑ Script error: No such module "citation/CS1".
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  13. ↑ Star Name - R.H. Allen p.160
  14. ↑ Template:In lang AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 11 日 Template:Webarchive
  15. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named CDS
  16. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named koen
  17. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named csiro
  18. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named kaler
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