Delta Herculis
Encyclopedia
Delta Herculis (δ Her, δ Herculis) is a fourth-magnitude star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
in the constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
Hercules
Hercules (constellation)
Hercules is a constellation named after Hercules, the Roman mythological hero adapted from the Greek hero Heracles. Hercules was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations today...
. It has the traditional name Sarin.
In Chinese
Chinese language
The Chinese language is a language or language family consisting of varieties which are mutually intelligible to varying degrees. Originally the indigenous languages spoken by the Han Chinese in China, it forms one of the branches of Sino-Tibetan family of languages...
, , meaning Left Wall of Heavenly Market Enclosure
Heavenly Market enclosure
Tian Shi Yuan, the Heavenly Market Enclosure , is one of the San Yuan or Three enclosures. Stars and constellations of this group are visible during late summer and early autumn in the Northern Hemisphere . The summer triangle lies directly to the northwest.-Asterisms:The asterisms are :...
, refers to an asterism which is represent eleven old states in China which is marking the left borderline of the enclosure, consisting of δ Herculis, λ Herculis
Lambda Herculis
Lambda Herculis is a star inthe constellation Hercules.It has the traditional name Maasym .In Chinese, , meaning Left Wall of Heavenly Market Enclosure, refers to an asterism which is represent eleven old states in China which is marking the left borderline of the enclosure, consisting of λ...
, μ Herculis
Mu Herculis
Mu Herculis is a nearby 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...
, ο Herculis
Omicron Herculis
Omicron Herculis is a multiple star system in the constellation Hercules. It has the traditional name Atia and the Flamsteed designation 103 Herculis.- Properties :...
, 112 Herculis, ζ Aquilae
Zeta Aquilae
Zeta Aquilae is a triple star system in the constellation Aquila. It has the traditional names Deneb el Okab, from an Arabic term ذنب العقاب ðanab al-cuqāb meaning "the tail of the falcon", and the Mandarin names Woo and Yuë, derived from and represent the state Wu , an old state was located at...
, θ1 Serpentis, η Serpentis
Eta Serpentis
Eta Serpentis is a binary star in the constellation Serpens. The primary, Eta Serpentis A, is an orange K-type giant with an apparent magnitude of +3.23. It has a distant 12th magnitude companion, Eta Serpentis B, 3 arcminutes away...
, ν Ophiuchi
Nu Ophiuchi
Nu Ophiuchi is a Class K0, third-magnitude star in the constellation Ophiuchus. Its closest stellar neighbour is the bright binary system Tau Ophiuchi, roughly 16.9 light years away from the star...
, ξ Serpentis
Xi Serpentis
Xi Serpentis is a triple star system in the constellation Serpens. The primary star, Xi Serpentis A, is a yellow-white F-type giant with an apparent magnitude of +3.54. It is a spectroscopic binary with an orbital period of 2.29 days. A 13th magnitude companion, Xi Serpentis B, is located 25...
and η Ophiuchi
Eta Ophiuchi
Eta Ophiuchi, also known as η Oph or η Ophiuchi, is a star in the constellation Ophiuchus. It also has the traditional name Sabik....
. Consequently, δ Herculis itself is known as , represent the state Wei
Wei (state)
The State of Wei was a Zhou Dynasty vassal state during the Warring States Period of Chinese history. Its territory lay between the states of Qin and Qi and included parts of modern day Henan, Hebei, Shanxi and Shandong...
(魏), together with 33 Capricorni (φ Capricorni
Phi Capricorni
Phi Capricorni is a star in the constellation Capricornus. φ Capricorni is an orange K-type bright giant with an apparent magnitude of +5.17...
and χ Capricorni
Chi Capricorni
Chi Capricorni is a star in the constellation Capricornus. χ Capricorni is a white A-type main sequence dwarf with an apparent magnitude of +5.30...
in R.H. Allen's version) in Twelve States
Girl (Chinese constellation)
The Girl mansion is one of the Twenty-eight mansions of the Chinese constellations. It is one of the northern mansions of the Black Tortoise.- Asterisms :...
(asterism).
In the catalogue of stars in the Calendarium of Al Achsasi al Mouakket
Al Achsasi al Mouakket
Mohammad Al Achsasi Al Mouakket was an Egyptian astronomer whose calendarium and catalogue of stars, entitled Durret al Muddiah Fih al Aamal al Shamsiah , was written at Cairo about 1650.Al Achsasi was sheikh of the Grand Mosque of the University of Cairo, where his name al...
, this star was designated Menkib al Jathi al Aisr, which was translated into Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
as Humerus Sinister Ingeniculi, meaning the left shoulder of the kneeling man.
Properties
Sarin is a complex star systemStar system
A star system or stellar system is a small number of stars which orbit each other, bound by gravitational attraction. A large number of stars bound by gravitation is generally called a star cluster or galaxy, although, broadly speaking, they are also star systems.-Binary star systems:A stellar...
consisting of at least 2 stars and possibly as many as 5. The main star is an A Type main sequence
Main sequence
The main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell...
subgiant with a stellar classification
Stellar classification
In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure...
A3IV. The subgiant has both a mass and radius that are roughly two times solar yielding a total luminosity
Luminosity
Luminosity is a measurement of brightness.-In photometry and color imaging:In photometry, luminosity is sometimes incorrectly used to refer to luminance, which is the density of luminous intensity in a given direction. The SI unit for luminance is candela per square metre.The luminosity function...
of about 18.5L☉ Though it only shines with an apparent magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
of 3.12, it the third brightest star in the Hercules
Hercules (constellation)
Hercules is a constellation named after Hercules, the Roman mythological hero adapted from the Greek hero Heracles. Hercules was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations today...
constellation. The most recent Hipparcos
Hipparcos
Hipparcos was a scientific mission of the European Space Agency , launched in 1989 and operated between 1989 and 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions of celestial objects on the sky...
data yields a distance estimate of approximately 23.1 parsecs (pc) from Earth or 75 light years (ly).
See also
- Lists of stars in the constellation Hercules
- Class A Stars
- Star systemStar systemA star system or stellar system is a small number of stars which orbit each other, bound by gravitational attraction. A large number of stars bound by gravitation is generally called a star cluster or galaxy, although, broadly speaking, they are also star systems.-Binary star systems:A stellar...
External links
- Jim Kaler's Stars, University of Illinois: DELTA HER (Delta Herculis)
- An Atlas of the Universe: Multiple Star Orbits