Mu Geminorum

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Template:Short description

μ Geminorum
Template:Location mark
Location of μ Geminorum (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Gemini
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) 2.75 - 3.02[2]
Characteristics
Evolutionary stage AGB[3]
Spectral type M3 III[4]
U−B Template:Engvar +1.924[5]
B−V Template:Engvar +1.643[5]
Variable type LB[2]
Astrometry
Radial velocity (Rv)Script error: No such module "val".[6] km/s
Proper motion (μ) RA: +56.39[1] mas/yr
Dec.: −110.03[1] mas/yr
Parallax (π)14.08±0.71 mas[1]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)−1.42[7]
Details
MassScript error: No such module "val".[8] Template:Solar mass
Radius107.7[9] Template:Solar radius
Luminosity1,692[10] Template:Solar luminosity
Surface gravity (log g)Script error: No such module "val".[11] cgs
Temperature3,643[8] K
Metallicity [Fe/H]Script error: No such module "val".[11] dex
Rotational velocity (v sin i)8.4[12] km/s
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Template:Odlist[13]
Database references
SIMBADdata

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Mu Geminorum or μ Geminorum, formally named Tejat (Template:IPAc-en),[14] is a single star in the northern constellation of Gemini. From parallax measurements obtained during the Hipparcos mission, it is roughly Script error: No such module "convert". distant from the Sun.[1] The position of the star near the ecliptic means that it is subject to lunar occultations.[15]

Mu Geminorum forms the primary or 'A' component of a double star system designated WDS J06230+2231 along with UCAC2 39641417[16] (also designated WDS J06230+2231BC), itself a binary pair.[17]

Nomenclature

File:Ic443 wide.jpg
μ Gem is the star on the left, surrounded by the S249 nebula. The bright star on the right, near the IC 443 supernova remnant, is η Gem.

μ Geminorum (Latinised to Mu Geminorum) is the star's Bayer designation. WDS J06230+2231 is the star's designation in the Washington Double Star Catalog.[18] The designations of the double star's components as WDS J06230+2231A and BC derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).[19] Further faint companions D, E, and F are also listed,[18] all distant background objects.[20]

Mu Geminorum bore the traditional name of Tejat (or more precisely, Tejat Posterior), from an old southern Arabic word of unknown meaning, tiḥyāt.[21] The name Tejat Posterior was formerly applied to an asterism consisting of this star, along with Gamma Geminorum (Alhena), Nu Geminorum, Eta Geminorum (Propus), and Xi Geminorum (Alzirr).[17] In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[22] to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[23] It approved the name Tejat for the component WDS J06230+2231A (i.e. Mu Geminorum) on February 1, 2017 and it is now so included in the List of IAU-approved Star Names.[14]

The names Calx (Latin, meaning 'heel'), Pish Pai (from the Persian پیش‌پای ('pīshpāy', meaning 'foreleg'), and Nuhatai (from Arabic 'Al Nuḥātai', the dual form of 'Al Nuḥāt', 'a Camel's Hump') have also been applied to Mu Geminorum.[24]

In Chinese, Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Well (asterism), refers to an asterism consisting of Mu Geminorum, Gamma Geminorum, Nu Geminorum, Xi Geminorum, Epsilon Geminorum, 36 Geminorum, Zeta Geminorum and Lambda Geminorum.[25] Consequently, Mu Geminorum itself is known as Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx).[26]

Properties

File:MuGemLightCurve.png
Visual band light curves for Mu Geminorum, adapted from Percy et al. (2001).[27] The 27 day periodicity is visible in the lower plot.

Mu Geminorum has an average apparent visual magnitude of about 2.9,[5][2] which makes it the fourth-brightest member of Gemini. It is 0.8 degrees south of the ecliptic, so it is subject to occultations by the Moon and, rarely, by planets.[28] Seen from Earth, its brightness is reduced by 0.07 magnitudes by extinction from intervening gas and dust.[6]

It is a slow irregular variable of type LB. Its brightness varies between magnitude +2.75 and +3.02 over a 72-day period, along with a 2,000-day period of long term variation. It is a red giant at a stellar classification of M3 III,[4] with a surface temperature of Script error: No such module "val".,[29] meaning it is considerably cooler than the Sun.[2] Despite being cooler than the Sun, it is over 1,500 times as luminous as it has expanded to more than 100 times the size of the Sun.[17]

Mu Geminorum is currently on the asymptotic giant branch and is generating energy through the nuclear fusion of hydrogen and helium along concentric shells surrounding an inert core of carbon and oxygen.[3]

References

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  1. ↑ a b c d e f Script error: No such module "citation/CS1".
  2. ↑ a b c d mu Gem, entry in the Combined General Catalog of Variable Stars (GCVS 5.1), N. N. Samus, O. V. Durlevich, et al., database identifier B/gcvs at the Centre de Données astronomiques de Strasbourg.
  3. ↑ a b Script error: No such module "citation/CS1".
  4. ↑ a b Script error: No such module "citation/CS1".
  5. ↑ a b c Script error: No such module "citation/CS1".
  6. ↑ a b Script error: No such module "citation/CS1".
  7. ↑ Script error: No such module "citation/CS1".
  8. ↑ a b Script error: No such module "citation/CS1".
  9. ↑ Script error: No such module "citation/CS1".
  10. ↑ Script error: No such module "citation/CS1".
  11. ↑ a b Script error: No such module "citation/CS1".
  12. ↑ Script error: No such module "citation/CS1".
  13. ↑ Template:Cite simbad
  14. ↑ a b Script error: No such module "citation/CS1".
  15. ↑ Script error: No such module "citation/CS1".
  16. ↑ Script error: No such module "citation/CS1".
  17. ↑ a b c Script error: No such module "citation/CS1".
  18. ↑ a b Script error: No such module "citation/CS1".
  19. ↑ Script error: No such module "citation/CS1".
  20. ↑ Template:Cite Gaia DR3
  21. ↑ Script error: No such module "citation/CS1".
  22. ↑ Script error: No such module "citation/CS1".
  23. ↑ Script error: No such module "citation/CS1".
  24. ↑ Script error: No such module "citation/CS1".
  25. ↑ 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.
  26. ↑ 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.
  27. ↑ Script error: No such module "citation/CS1".
  28. ↑ Script error: No such module "citation/CS1".
  29. ↑ Script error: No such module "citation/CS1".

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External links

Template:Stars of Gemini

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