Mu Herculis

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Mu Herculis
File:Hercules Historical View.png
Historical view of the Hercules constellation showing Mu Herculis (μ Her) as one of stars in the hero's elbow.
Observation data
Epoch J2000      Equinox J2000
Constellation Hercules
μ Her Aab (μ1 Her)
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) 3.417 ± 0.014[1]
μ Her BC (μ2 Her)
Right ascension Template:RA[2]
Declination Template:DEC[2]
Apparent magnitude (V) 10.2 / 10.7[3]
Characteristics
μ Her Aab
Spectral type G5IV[4] / M4V[5]
U−B Template:Engvar +0.40[6]
B−V Template:Engvar +0.76[6]
μ Her BC
Spectral type M3.5V[7]
U−B Template:Engvar +1.00[6]
B−V Template:Engvar +1.50[6]
Astrometry
μ Her Aab
Radial velocity (Rv)−17.07 ± 0.12[8] km/s
Proper motion (μ) RA: −291.66[1] mas/yr
Dec.: −749.60[1] mas/yr
Parallax (π)120.33±0.16 mas[1]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)3.82 ± 0.02[8]
μ Her BC
Proper motion (μ) RA: −343.35[9] mas/yr
Dec.: −743.88[9] mas/yr
Parallax (π)119.8871±0.2055 mas[10]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)+10.26[11]
Orbit[5]
Primaryμ Her Aa
Companionμ Her Ab
Period (P)98.9 ± 22.7 yr
Semi-major axis (a)2.9 ± 0.3″
Eccentricity (e)0.44 ± 0.06
Inclination (i)62.82 ± 4.66°
Longitude of the node (Ω)80.4 ± 1.7°
Periastron epoch (T)B 1921.1 ± 23.8
Argument of periastron (ω)
(secondary)		214 ± 16°
Semi-amplitude (K1)
(primary)		1.12 ± 0.10 km/s
Orbit[3]
Primaryμ Her B
Companionμ Her C
Period (P)43.127 ± 0.013 yr
Semi-major axis (a)1.385 ± 0.038″
Eccentricity (e)0.1796 ± 0.0009
Inclination (i)66.06 ± 0.15°
Longitude of the node (Ω)60.07 ± 0.17°
Periastron epoch (T)B 2008.335 ± 0.073
Argument of periastron (ω)
(secondary)		172.85 ± 0.64°
Details
μ Her Aa
Mass1.11 ± 0.01[8] Template:Solar mass
RadiusScript error: No such module "val".[12] Template:Solar radius
LuminosityScript error: No such module "val".[12] Template:Solar luminosity
Surface gravity (log g)Script error: No such module "val".[12] cgs
TemperatureScript error: No such module "val".[12] K
Metallicity [Fe/H]+Script error: No such module "val".[12] dex
RotationScript error: No such module "val". d[8]
Rotational velocity (v sin i)1.7 ± 0.4[8] km/s
AgeScript error: No such module "val".[8] Gyr
μ Her Ab
Mass0.32[5] Template:Solar mass
Metallicity [Fe/H]{{{metal_fe2}}} dex
μ Her B
Mass0.44[13] Template:Solar mass
Radius0.60[14] Template:Solar radius
Luminosity0.087[14] Template:Solar luminosity
Temperature4,050[14] K
Metallicity [Fe/H]+0.21[14] dex
μ Her C
Mass0.39[13] Template:Solar mass
RadiusScript error: No such module "val".[15] Template:Solar radius
TemperatureScript error: No such module "val".[15] K
MetallicityTemplate:M/H[15]
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
86 Herculis, Gl 695, HR 6623, BD+27°2888, HD 161797, LHS 3326/3325, LTT 15266, SAO 85397, FK5 667, LFT 1374, GC 24138, ADS 10786, HIP 86974.[16]
Database references
SIMBADμ Her Aab
μ Her BC

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Mu Herculis (μ Herculis) is a nearby quadruple star system about 27.1 light years from Earth in the constellation Hercules. Its main star, Mu Herculis A is fairly similar to the Sun although more highly evolved with a stellar classification of G5 IV. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[17] Its mass is about 1.1 times that of the Sun,[8] and it is beginning to expand to become a giant.

Etymology

In the catalogue of stars in the Calendarium of Al Achsasi Al Mouakket, this star was designated Marfak Al Jathih Al Aisr, which was translated into Latin as Cubitum Sinistrum Ingeniculi, meaning the left elbow of kneeling man.[18]

In Chinese, Script error: No such module "Lang". (Script error: No such module "Lang".), the Left Wall of Heavenly Market Enclosure, refers to an asterism which represents eleven old states in China, marking the left borderline of the enclosure, consisting of μ Herculis, δ Herculis, λ Herculis, ο Herculis, 112 Herculis, ζ Aquilae, θ1 Serpentis, η Serpentis, ν Ophiuchi, ξ Serpentis and η Ophiuchi.[19] Consequently, the Chinese name for μ Herculis itself is Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx), represent Jiuhe (九河, lit. meaning nine rivers), possibly for Jiujiang, the prefecture-level city in Jiangxi, China, which is the same literally meaning with Jiuhe.[20][21] From this Chinese title, the name Kew Ho appeared.[22]

Star system

Mu Herculis is a quadruple star system. The brightest star is a well-studied G-type subgiant, whose parameters are precisely determined from asteroseismology.[8] It was believed to be a close binary with a low-mass stellar or a large substellar companion. This was confirmed when low-mass companion was resolved using near-infrared spectroscopy.[5] The companion star is a red dwarf with a spectral type of M4V and a mass of Template:Solar mass.[5] This pair is also known as Mu1 Herculis.

The secondary component, also known as Mu2 Herculis,[23] consists of a pair of stars that orbit about each other with a period of about 43 years.[24] Mu Herculis A and the binary pair B-C are separated by some 35 arcseconds.[16] The stars B and C, which orbit each other, are separated from each other by 1.385 arcseconds, and have a slightly eccentric orbit, at 0.1796.[3]

See also

References

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  1. ↑ a b c d e f Script error: No such module "citation/CS1".
  2. ↑ a b Script error: No such module "Citation/CS1".
  3. ↑ a b c Script error: No such module "citation/CS1".
  4. ↑ Script error: No such module "citation/CS1".
  5. ↑ a b c d e Script error: No such module "Citation/CS1".
  6. ↑ a b c d Script error: No such module "Citation/CS1".
  7. ↑ Script error: No such module "Citation/CS1".Script error: No such module "Unsubst".
  8. ↑ a b c d e f g h Script error: No such module "Citation/CS1".
  9. ↑ a b Script error: No such module "Citation/CS1".
  10. ↑ Template:Cite Gaia EDR3
  11. ↑ Script error: No such module "Citation/CS1".
  12. ↑ a b c d e Script error: No such module "Citation/CS1".
  13. ↑ a b Script error: No such module "citation/CS1".
  14. ↑ a b c d Script error: No such module "Citation/CS1".
  15. ↑ a b c Script error: No such module "Citation/CS1".
  16. ↑ a b Template:Cite simbad
  17. ↑ Script error: No such module "citation/CS1".
  18. ↑ Script error: No such module "citation/CS1".
  19. ↑ 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.
  20. ↑ Template:In lang AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 23 日 Template:Webarchive
  21. ↑ Template:In lang English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name Template:Webarchive, Hong Kong Space Museum. Accessed on line November 23, 2010.
  22. ↑ Star Name - R.H. Allen p. 238
  23. ↑ Template:Cite simbad
  24. ↑ Script error: No such module "citation/CS1".

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External links

Template:Stars of Hercules

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