Beta Gruis

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Beta Gruis
Template:Location mark
Location of β Gruis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Grus
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) 2.146[2] (2.0 - 2.3[3])
Characteristics
Evolutionary stage AGB[4]
Spectral type M4.5 III[5]
U−B Template:Engvar +1.757[2]
B−V Template:Engvar +1.620[2]
Variable type SRb[3]
Astrometry
Radial velocity (Rv)+1.6[6] km/s
Proper motion (μ) RA: +135.16[1] mas/yr
Dec.: −4.38[1] mas/yr
Parallax (π)18.43±0.42 mas[1]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)Script error: No such module "val".[7]
Details
Mass2.4[8] Template:Solar mass
Radius154[9] Template:Solar radius
LuminosityScript error: No such module "val".[9] Template:Solar luminosity
Surface gravity (log g)0.4[10] cgs
TemperatureScript error: No such module "val".[9] K
Metallicity [Fe/H]0.0[10] dex
Age450[11] Myr
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Tiaki, Beta Gru, CD−47 14308, FK5 856, HR 8636, HD 214952, HIP 112122, SAO 231258.[12]
Database references
SIMBADdata

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Beta Gruis (β Gruis, abbreviated Beta Gru, β Gru), formally named Tiaki Template:IPAc-en,[13] is the second brightest star in the southern constellation of Grus. It was once considered the rear star in the tail of the constellation of the (Southern) Fish, Piscis Austrinus: it, with Alpha, Delta, Theta, Iota, and Lambda Gruis, belonged to Piscis Austrinus in medieval Arabic astronomy.[14]

Nomenclature

β Gruis (Latinised to Beta Gruis) is the star's Bayer designation.

It bore the traditional Tuamotuan name of Tiaki.[15] In 2016, the IAU organized a Working Group on Star Names (WGSN)[16] to catalog and standardize proper names for stars. The WGSN approved the name Tiaki for this star on 5 September 2017 and it is now so included in the List of IAU-approved Star Names.[13]

In Chinese, Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Crane, refers to an asterism consisting of Beta Gruis, Alpha Gruis, Epsilon Gruis, Eta Gruis, Delta Tucanae, Zeta Gruis, Iota Gruis, Theta Gruis, Delta² Gruis and Mu¹ Gruis.[17] Consequently, Beta Gruis itself is known as Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx).[18] The Chinese name gave rise to another English name, Ke.[19]

Properties

File:BetaGruLightCurve.png
A visual band light curve for Beta Gruis, plotted from data published by Otero and Moon (2006).[3] The inset plot shows the points plotted in red with an expanded scale.

Beta Gruis is a red giant star[3] on the asymptotic giant branch[4] with an estimated mass of about 2.4 times that of the Sun[20] and a surface temperature of approximately 3,500 K, just over half the surface temperature of the Sun.[9] This low temperature accounts for the dull red color of an M-type star. The total luminosity is about 3,200 times that of the Sun, and it has 150 times the Sun's radius.[9]

It is one of the brightest stars at infrared and near-infrared wavelenghts. At the K band, it is the fifth-brightest star in the night sky.[21]

Alan William James Cousins announced that Beta Gruis is a variable star in 1952.[22] Beta Gruis is a semiregular variable (SRb) star that varies in magnitude by about 0.4. It varies between intervals when it displays regular changes with a 37-day periodicity and times when it undergoes slow irregular variability.[3]

References

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  1. ↑ a b c d e Script error: No such module "citation/CS1".
  2. ↑ a b c Script error: No such module "citation/CS1".
  3. ↑ a b c d e Script error: No such module "citation/CS1".
  4. ↑ a b Script error: No such module "Citation/CS1".
  5. ↑ Script error: No such module "Citation/CS1".
  6. ↑ Script error: No such module "citation/CS1".
  7. ↑ Script error: No such module "citation/CS1".
  8. ↑ Script error: No such module "citation/CS1".
  9. ↑ a b c d e Script error: No such module "Citation/CS1".
  10. ↑ a b Script error: No such module "citation/CS1".
  11. ↑ Script error: No such module "citation/CS1".
  12. ↑ Script error: No such module "citation/CS1".
  13. ↑ a b Script error: No such module "citation/CS1".
  14. ↑ Script error: No such module "citation/CS1".
  15. ↑ Script error: No such module "citation/CS1".
  16. ↑ Script error: No such module "citation/CS1".
  17. ↑ Template:In lang 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, Template:ISBN.
  18. ↑ Template:In lang 香港太空館 - 研究資源 - 亮星中英對照表 Template:Webarchive, Hong Kong Space Museum. Accessed on line November 23, 2010.
  19. ↑ Richard Hinckley Allen: Star Names — Their Lore and Meaning: Grus
  20. ↑ Script error: No such module "citation/CS1".
  21. ↑ Script error: No such module "citation/CS1".
  22. ↑ Script error: No such module "Citation/CS1".

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External links

Template:Stars of Grus

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Template:Sky

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