Epsilon Aquilae
Encyclopedia
Epsilon Aquilae (ε Aql, ε Aquilae) is a triple star system in the constellation
Aquila
. It has the traditional name Deneb el Okab, from an Arabic
term ذنب العقاب ðanab al-cuqāb meaning "the tail of the eagle", and the Mandarin
names Woo and Yuë, derived from and represent the state Wu
(吳), an old state was located at the mouth of the Yangtze River
, and Yue
(越), an old state in Zhejiang
province (together with 19 Capricorni in Twelve States
asterism). According to the R.H. Allen's works, it names shares with ζ Aquilae
.. Epsilon Aquilae is more precisely called Deneb el Okab Borealis, because is situated to the north of Zeta Aquilae, which can therefore be called Deneb el Okab Australis.
The primary component, ε Aquilae A, is an orange K-type
giant
with an apparent magnitude
of +4.02. It has two 10th-magnitude companions separated from the primary by 131.1 and 148.6 arcseconds, but perhaps they are only optical binaries. Epsilon Aquilae is approximately 154 light years
from Earth
. It is a so-called barium star
; therefore its atmosphere is extremely enriched with barium
and other heavy elements.
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 has the traditional name Deneb el Okab, from an Arabic
Arabic language
Arabic is a name applied to the descendants of the Classical Arabic language of the 6th century AD, used most prominently in the Quran, the Islamic Holy Book...
term ذنب العقاب ðanab al-cuqāb meaning "the tail of the eagle", and the Mandarin
Standard Mandarin
Standard Chinese or Modern Standard Chinese, also known as Mandarin or Putonghua, is the official language of the People's Republic of China and Republic of China , and is one of the four official languages of Singapore....
names Woo and Yuë, derived from and represent the state Wu
Wu (state)
The State of Wu , also known as Gou Wu or Gong Wu , was one of the vassal states during the Western Zhou Dynasty and the Spring and Autumn Period. The State of Wu was located at the mouth of the Yangtze River east of the State of Chu. Considered a semi-barbarian state by ancient Chinese...
(吳), an old state was located at the mouth of the Yangtze River
Yangtze River
The Yangtze, Yangzi or Cháng Jiāng is the longest river in Asia, and the third-longest in the world. It flows for from the glaciers on the Tibetan Plateau in Qinghai eastward across southwest, central and eastern China before emptying into the East China Sea at Shanghai. It is also one of the...
, and Yue
Yue (state)
Yue was a state in China which existed during the Spring and Autumn Period and the Warring States Period , in the modern province of Zhejiang. During the Spring and Autumn Period, its capital was in Guiji , near the modern city of Shaoxing...
(越), an old state in Zhejiang
Zhejiang
Zhejiang is an eastern coastal province of the People's Republic of China. The word Zhejiang was the old name of the Qiantang River, which passes through Hangzhou, the provincial capital...
province (together with 19 Capricorni 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). According to the R.H. Allen's works, it names shares with 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...
.. Epsilon Aquilae is more precisely called Deneb el Okab Borealis, because is situated to the north of Zeta Aquilae, which can therefore be called Deneb el Okab Australis.
The primary component, ε Aquilae A, is an orange K-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...
giant
Giant star
A giant star is a star with substantially larger radius and luminosity than a main sequence star of the same surface temperature. Typically, giant stars have radii between 10 and 100 solar radii and luminosities between 10 and 1,000 times that of the Sun. Stars still more luminous than giants are...
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 +4.02. It has two 10th-magnitude companions separated from the primary by 131.1 and 148.6 arcseconds, but perhaps they are only optical binaries. Epsilon Aquilae is approximately 154 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
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
. It is a so-called barium star
Barium star
Barium stars are G to K class giants, whose spectra indicate an overabundance of s-process elements by the presence of singly ionized barium, Ba II, at λ 455.4nm. Barium stars also show enhanced spectral features of carbon, the bands of the molecules CH, CN and C2...
; therefore its atmosphere is extremely enriched with barium
Barium
Barium is a chemical element with the symbol Ba and atomic number 56. It is the fifth element in Group 2, a soft silvery metallic alkaline earth metal. Barium is never found in nature in its pure form due to its reactivity with air. Its oxide is historically known as baryta but it reacts with...
and other heavy elements.