Mu Herculis (μ Herculis) is a nearby quadruple

star system A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction. A large group of stars bound by gravitation is generally called a '' star cluster'' or ''galaxy'', although, broadly speakin ...

about 27.1

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 from Earth in the constellation

Hercules Hercules (, ) is the Roman equivalent of the Greek divine hero Heracles, son of Jupiter and the mortal Alcmena. In classical mythology, Hercules is famous for his strength and for his numerous far-ranging adventures. The Romans adapted th ...

. Its main star, Mu Herculis A is fairly similar to the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared rad ...

although more highly

evolved Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation te ...

with a

stellar classification In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting t ...

of G5 IV. Since 1943, the

spectrum A spectrum (plural ''spectra'' or ''spectrums'') is a condition that is not limited to a specific set of values but can vary, without gaps, across a continuum. The word was first used scientifically in optics to describe the rainbow of color ...

of this star has served as one of the stable anchor points by which other stars are classified. Its mass is about 1.1 times that of the Sun, 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 Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power ...

as ''Cubitum Sinistrum Ingeniculi'', meaning ''the left elbow of kneeling man''. 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 v ...

, (), 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 Delta Herculis (δ Herculis, abbreviated Delta Her, δ Her) is a multiple star system in the constellation of Hercules. Its light produces to us apparent magnitude 3.12, as such the third-brightest star in the large, fairly dim constella ...

λ Herculis Lambda Herculis (λ Herculis. abbreviated Lambda Her, λ Her), formally named Maasym , is a star in the constellation of Hercules. From parallax measurements taken during the Gaia mission, it is approximately 393 light-years from the Sun. ...

, ο Herculis,

112 Herculis 112 Herculis is a binary star system in the northern constellation of Hercules. It is dimly visible to the naked eye with a combined apparent visual magnitude of 5.43. The secondary component is about two magnitudes fainter than the pr ...

ζ Aquilae Zeta Aquilae, or ζ Aquilae, is a binary star system in the equatorial constellation of Aquila. It is readily visible with the naked eye, being of the third magnitude. Based on parallax measurements obtained during the Hipparcos mission, ...

, θ¹ Serpentis, η Serpentis, ν Ophiuchi, ξ Serpentis and

η Ophiuchi Eta Ophiuchi (η Ophiuchi, abbreviated Eta Oph, η Oph) is a binary star in the constellation of Ophiuchus. Based on parallax measurements taken during the Hipparcos mission, it is approximately 88 light-years from the Sun. Eta Ophiuc ...

. Consequently, the

Chinese name Chinese names or Chinese personal names are names used by individuals from Greater China and other parts of the Chinese-speaking world throughout East and Southeast Asia (ESEA). In addition, many names used in Japan, Korea and Vietnam are oft ...

for μ Herculis itself is (, en, the Third Star of Left Wall of Heavenly Market Enclosure), represent ''Jiuhe'' (九河, lit. meaning ''nine rivers''), possibly for

Jiujiang Jiujiang (), formerly transliterated Kiukiang or Kew Keang, is a prefecture-level city located on the southern shores of the Yangtze River in northwest Jiangxi Province, People's Republic of China. It is the second-largest prefecture-level city ...

, the prefecture-level city in Jiangxi, China, which is the same literally meaning with ''Jiuhe''. From this Chinese title, the name ''Kew Ho'' appeared.Star Name - R.H. Allen p. 238
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Star system

Mu Herculis is a quadruple star system. The brightest star is a well-studied

G-type Gaea Gaea is one of the Elder Gods of Earth. Gaia Gaia, also known as the Guardian of the Universal Amalgamator, is a fictional superhero, depicted as possibly being a mutant or extraterrestrial. Created by Larry Hama, she first appeared in ...

subgiant A subgiant is a star that is brighter than a normal main-sequence star of the same spectral class, but not as bright as giant stars. The term subgiant is applied both to a particular spectral luminosity class and to a stage in the evolution ...

, whose parameters are precisely determined from

asteroseismology Asteroseismology or astroseismology is the study of oscillations in stars. Stars have many resonant modes and frequencies, and the path of sound waves passing through a star depends on the speed of sound, which in turn depends on local temperatur ...

. 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 Near-infrared spectroscopy (NIRS) is a spectroscopic method that uses the near-infrared region of the electromagnetic spectrum (from 780 nm to 2500 nm). Typical applications include medical and physiological diagnostics and research inc ...

. The companion star is a

red dwarf ''Red Dwarf'' is a British science fiction comedy franchise created by Rob Grant and Doug Naylor, which primarily consists of a television sitcom that aired on BBC Two between 1988 and 1999, and on Dave (TV channel), Dave since 2009, gaining a ...

with a

spectral type In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting th ...

of M4V and a mass of . This pair is also known as Mu¹ Herculis. The secondary component, also known as Mu² Herculis, consists of a pair of stars that orbit about each other with a period of about 43 years. Mu Herculis A and the binary pair B-C are separated by some 35 arcseconds. 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.

References

External links

*Jim Kaler's Stars, University of Illinois
MU HER (Mu Herculis)
*SolStation

{{DEFAULTSORT:Mu Herculis Hercules (constellation) 4 G-type subgiants M-type main-sequence stars Herculis, Mu Herculis, Mu Herculis, 086 086974 6623 0695 Durchmusterung objects 161797

Etymology

Star system

See also

References

External links