Beta Aquilae, Latinized from β Aquilae, is a triple star system in the equatorial constellation of Aquila. It is visible to the naked eye as a point-like source with an

apparent visual magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's lig ...

of 3.87. Based on parallax measurements obtained during the Hipparcos mission, it is located at a distance of approximately 44.7

light-years 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 ...

from 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 radi ...

. It is drifting closer to the Sun with a radial velocity of −40 km/s. Its two components are designated Beta Aquilae A (formally named Alshain , the traditional name for the system) and B.

Nomenclature

''β Aquilae'' (Latinised to ''Beta Aquilae'') is the system's Bayer designation. The designations of the two components as ''Beta Aquilae A'' and ''B'' derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the

International Astronomical Union The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...

(IAU). The system bore the traditional name ''Alshain'' derived from the Perso-

Arabic Arabic (, ' ; , ' or ) is a Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C. E.Watson; Walter ...

term الشاهين, ''aš-šāhīn'', meaning "the (peregrine) falcon", perhaps by folk etymology from the

Persian Persian may refer to: * People and things from Iran, historically called ''Persia'' in the English language ** Persians, the majority ethnic group in Iran, not to be conflated with the Iranic peoples ** Persian language, an Iranian language of the ...

''šāhīn tarāzū'' (or possibly ''šāhīn tara zed''; see Gamma Aquilae), the Persian name for the asterism α, β and

γ Aquilae Gamma Aquilae, Latinized from γ Aquilae, and formally known as Tarazed , is a star in the constellation of Aquila. It has an apparent visual magnitude of 2.712, making it readily visible to the naked eye at night. Parallax measureme ...

. In 2016, the IAU organized a

Working Group on Star Names The International Astronomical Union (IAU) established a Working Group on Star Names (WGSN) in May 2016 to catalog and standardize proper names for stars for the international astronomical community. It operates under Division C – Education ...

(WGSN) to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems. It approved the name ''Alshain'' for the component Beta Aquilae A on 21 August 2016 and it is now so included in the List of IAU-approved Star Names. In the catalogue of stars in the ''Calendarium'' of

Al Achsasi al Mouakket Muḥammad al-Akhṣāṣī al-Muwaqqit ( ar, محمد الاخصاصي الموقت) was an Egyptian astronomer whose and catalogue of stars, ('Pearls of brilliance upon the solar operations'), was written at Cairo about 1650. Al-Akhsasi was a s ...

, this star was designated ''Unuk al Ghyrab'' (عنق ألغراب - ''únuq al-ghuraab''), 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 of the ...

as ''Collum Corvi'', meaning ''the crow's neck''. 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 ...

, (), meaning '' River Drum'', refers to an asterism consisting of Beta Aquilae,

Altair Altair is the brightest star in the constellation of Aquila and the twelfth-brightest star in the night sky. It has the Bayer designation Alpha Aquilae, which is Latinised from α Aquilae and abbreviated Alpha Aql ...

and Gamma Aquilae. 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 ofte ...

for Beta Aquilae itself is (, en, the First Star of River Drum).

Namesake

was a United States navy ship.

Properties

The primary, component A, is of

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

3.71 and

spectral class 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 the ...

G8IV. It has a very low level of surface magnetic activity and may be in a state similar to a Maunder minimum. The activity shows a cycle of . 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 colors ...

of this star has served as one of the stable anchor points by which other stars are classified. This is an aging

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 ...

star that has exhausted the supply of hydrogen at its core and is

evolving 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 t ...

into a

giant In folklore, giants (from Ancient Greek: ''gigas'', cognate giga-) are beings of human-like appearance, but are at times prodigious in size and strength or bear an otherwise notable appearance. The word ''giant'' is first attested in 1297 fr ...

. It has a mass 26% greater than the Sun's, a luminosity six times that of the Sun, and a radius about thrice solar. The 12th magnitude secondary companion, designated component B, is a double-lined spectroscopic binary which is 13 arcseconds away in the sky. It has a stellar classification of M2.5 V, matching a class M red dwarf.

In culture

In the Chinese folk tale ''

The Cowherd and the Weaver Girl "The Cowherd and the Weaver Girl" are characters found in Chinese mythology and characters appearing eponymously in a romantic Chinese folk tale. The story tells of the romance between Zhinü (; the weaver girl, symbolizing the star Vega) and N ...

'', Beta and Gamma Aquilae are children of Niulang (牛郎, The Cowherd,

) and Zhinü (織女, The Princess,

Vega Vega is the brightest star in the northern constellation of Lyra. It has the Bayer designation α Lyrae, which is Latinised to Alpha Lyrae and abbreviated Alpha Lyr or α Lyr. This star is relatively close at only from the Sun, a ...

). The Koori people of

Victoria Victoria most commonly refers to: * Victoria (Australia), a state of the Commonwealth of Australia * Victoria, British Columbia, provincial capital of British Columbia, Canada * Victoria (mythology), Roman goddess of Victory * Victoria, Seychelle ...

knew Beta and Gamma Aquilae as the black swan wives of ''Bunjil'' (Altair), the

wedge-tailed eagle The wedge-tailed eagle (''Aquila audax'') is the largest bird of prey in the continent of Australia. It is also found in southern New Guinea to the north and is distributed as far south as the state of Tasmania. Adults of this species have lon ...

References

External links

*
ARICNS

by Professor Jim Kaler.
Image β Aquilae
{{DEFAULTSORT:Beta Aquilae G-type subgiants Aquilae, Beta Maunder Minimum Suspected variables Triple stars Spectroscopic binaries Aquila (constellation) Aquilae, Beta Durchmusterung objects Aquilae, 60 0771 188512 098036 7602 Alshain