Delta Aquilae
Encyclopedia
Delta Aquilae (δ Aql, δ Aquilae) is a triple star system 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....

 Aquila
Aquila (constellation)
Aquila is a stellar constellation. Its name is Latin for 'eagle' and it is commonly represented as such. In mythology, Aquila was owned by the Roman god Jupiter and performed many tasks for him....

. It is approximately 50.1 light years
Light Years
Light Years is the seventh studio album by Australian recording artist Kylie Minogue. It was released on 25 September 2000 by Parlophone and Mushroom Records. The album's style was indicative of her return to "mainstream pop dance tunes"....

 from Earth.

Sometimes, this star is called by the name Denebokab, meaning the tail of eagle in Arabic. 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 Right Flag
Ox (Chinese constellation)
The Ox mansion is one of the Twenty-eight mansions of the Chinese constellations. It is one of the northern mansions of the Black Tortoise.-Asterisms:...

, refers to an asterism consisting of δ Aquilae, μ Aquilae, σ Aquilae
Sigma Aquilae
Sigma Aquilae is a binary star in the constellation Aquila. It is approximately 680 light years from Earth.Sigma Aquilae is an eclipsing spectroscopic binary. Both components are detached blue-white B-type main sequence dwarfs which do not fill their Roche lobes. The mean apparent magnitude of...

, ν Aquilae
Nu Aquilae
Nu Aquilae is a star in the constellation Aquila.Nu Aquilae is a yellow-white F-type supergiant with an apparent magnitude of +4.64. It is at least 3000 light years from Earth and lies close to the celestial equator.-References:...

, ι Aquilae, 42 Aquilae
42 Aquilae
42 Aquilae is a star in the constellation Aquila. Its apparent magnitude is 5.45....

, HD 184701, κ Aquilae
Kappa Aquilae
Kappa Aquilae is a star in the constellation Aquila.Kappa Aquilae is a blue-white B-type giant with an apparent magnitude of +4.93. It is approximately 1460 light years from Earth.-References:* * *...

 and 56 Aquilae
56 Aquilae
56 Aquilae is a star in the constellation Aquila. Its apparent magnitude is 5.76, meaning it would be barely visible to the naked eye, under ideal conditions.It was discovered by nineteenth Century Astronomer John Herschel....

. Consequently, δ Aquilae itself is known as

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 Djenubi Menkib al Nesr (منكب ألنسر ألخنوبي - mankib al-nasr al-janúbii), 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 Australior Humerus Vulturis, meaning the southern shoulder of the eagle.

This star, along with η Aql
Eta Aquilae
Eta Aquilae is a star in the constellation Aquila. It was also part of the former constellation Antinous. It is a Cepheid variable star, varying from apparent magnitude 3.5 to 4.4 with a period of 7.176641 days...

 and θ Aql
Theta Aquilae
Theta Aquilae is a binary star in the constellation Aquila. It is approximately 287 light years from Earth. It has the traditional name Tseen Foo, which is derived from the Mandarin 天桴 tiānfú meaning "the heavenly raft"; it may also mean drumsticks, with Altair, Beta Aquilae and Gamma Aquilae...

 (Tseen Foo) and, were Al Mizān (ألميزان), the Scale-beam. According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al Mizān were the title for three stars :δ Aql as Al Mizān I, η Aql
Eta Aquilae
Eta Aquilae is a star in the constellation Aquila. It was also part of the former constellation Antinous. It is a Cepheid variable star, varying from apparent magnitude 3.5 to 4.4 with a period of 7.176641 days...

 as l Mizān II and θ Aql
Theta Aquilae
Theta Aquilae is a binary star in the constellation Aquila. It is approximately 287 light years from Earth. It has the traditional name Tseen Foo, which is derived from the Mandarin 天桴 tiānfú meaning "the heavenly raft"; it may also mean drumsticks, with Altair, Beta Aquilae and Gamma Aquilae...

 as Al Mizān III

Structure

Delta Aquilae is an astrometric binary. The visible component is a yellow-white F-type
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...

 subgiant 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 +3.36. The orbital period of the binary is 3.422 years. The visible component is also a spectroscopic binary, bringing the total number of components to three. The spectroscopic binary has an orbital period of 3.77 hours.

External links

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