Beta Aquarii is a single

yellow supergiant A yellow supergiant (YSG) is a star, generally of spectral type F or G, having a supergiant luminosity class (e.g. Ia or Ib). They are stars that have evolved away from the main sequence, expanding and becoming more luminous. Yellow supergiants ...

star A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...

in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

of Aquarius. It has the official name Sadalsuud () and the

Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek alphabet, Greek or Latin letter followed by the genitive case, genitive form of its parent constellation's Latin name. The original list of Bayer design ...

β Aquarii, abbreviated Beta Aqr or β Aqr. Based upon

parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different sightline, lines of sight and is measured by the angle or half-angle of inclination between those two lines. Due to perspective (graphica ...

measurements obtained during the

Hipparcos ''Hipparcos'' was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions and distances of ...

mission, this component is located at a distance of approximately 540

light year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distance, astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by t ...

s (165

parsecs The parsec (symbol: pc) is a unit of length used to measure the large distances to astronomical objects outside the Solar System, approximately equal to or (AU), i.e. . The parsec unit is obtained by the use of parallax and trigonometry, and ...

) from the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

. It is drifting further away with a

radial velocity The radial velocity or line-of-sight velocity of a target with respect to an observer is the rate of change of the vector displacement between the two points. It is formulated as the vector projection of the target-observer relative velocity ...

of 6.5 km/s. The star serves as an

IAU The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...

radial velocity standard.

Nomenclature

''β Aquarii'', Latinised to ''Beta Aquarii'', is the star's

. It bore the traditional name ''Sadalsuud'', from an

Arabic Arabic (, , or , ) is a Central Semitic languages, Central Semitic language of the Afroasiatic languages, Afroasiatic language family spoken primarily in the Arab world. The International Organization for Standardization (ISO) assigns lang ...

expression سعد السعود (''sa‘d al-su‘ūd''), the "luck of lucks". Other spellings that were sometimes encountered were ''Sad es Saud'', ''Sadalsund'', and ''Saad el Sund''. In the catalogue of stars in the ''Calendarium of Al Achsasi Al Mouakket'', this star was designated ''Nir Saad al Saaoud'', which was translated into

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

as ''Lucida Fortunæ Fortunarum'' (rather identic with R.H. Allen), meaning ''the brightest of luck of lucks''. The

International Astronomical Union The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...

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) has approved the name ''Sadalsuud'' for the primary or 'A' component. In Chinese, (), meaning ''

Emptiness Emptiness as a human condition is a sense of generalized boredom, social alienation, nihilism, and apathy. Feelings of emptiness often accompany dysthymia, depression (mood), depression, loneliness, anhedonia, wiktionary:despair, despair, or o ...

(asterism)'', refers to an asterism consisting of Beta Aquarii and Alpha Equulei. Consequently, the

Chinese name Chinese may refer to: * Something related to China * Chinese people, people identified with China, through nationality, citizenship, and/or ethnicity **Han Chinese, East Asian ethnic group native to China. **'' Zhonghua minzu'', the supra-ethni ...

for Beta Aquarii itself is (, ). ''Sadalsuud'' is found in

Hindu Hindus (; ; also known as Sanātanīs) are people who religiously adhere to Hinduism, also known by its endonym Sanātana Dharma. Jeffery D. Long (2007), A Vision for Hinduism, IB Tauris, , pp. 35–37 Historically, the term has also be ...

texts as ''Kalpeny'' and, in the context of the ancient Indian system of astronomy, Jyotisha Veda, is located in the 23rd

Nakshatra Nakshatra () is the term for Lunar mansion in Hindu astrology and Buddhist astrology. A nakshatra is one of 27 (sometimes also 28) sectors along the ecliptic. Their names are related to a prominent star or asterisms in or near the respective s ...

Shravishthā, a lunar mansion which is ruled by Eight

vasu The Vasus () are a group of deities in Hinduism associated with fire and light. They are described as the attendant deities of Indra, and later Vishnu. Generally numbering eight and classified as the Ashtavasu, they are described in the Ramayana a ...

s - the ''"deities of earthly abundance"'' . On the

Euphrates The Euphrates ( ; see #Etymology, below) is the longest and one of the most historically important rivers of West Asia. Tigris–Euphrates river system, Together with the Tigris, it is one of the two defining rivers of Mesopotamia (). Originati ...

, ''Sadalsuud'' was known as ''Kakkab Nammax'', the Star of Mighty Destiny; that may have given origin to the title of the manzil, as well as to the

astrologers Astrology is a range of divinatory practices, recognized as pseudoscientific since the 18th century, that propose that information about human affairs and terrestrial events may be discerned by studying the apparent positions of celesti ...

' name for it — ''Fortuna Fortunarum''.

Properties

β Aquarii is the brightest star in Aquarius with an

apparent magnitude Apparent magnitude () is a measure of the Irradiance, brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction (astronomy), ...

of 2.87 and a

stellar classification In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction gratin ...

of G0 Ib. Since 1943, the

spectrum A spectrum (: spectra or spectrums) is a set of related ideas, objects, or properties whose features overlap such that they blend to form a continuum. The word ''spectrum'' was first used scientifically in optics to describe the rainbow of co ...

of this star has served as one of the stable anchor points by which other stars are classified. It has an estimated age of 56 million years; old enough for a star of this mass to evolve into a

supergiant Supergiants are among the most massive and most luminous stars. Supergiant stars occupy the top region of the Hertzsprung–Russell diagram, with absolute visual magnitudes between about −3 and −8. The temperatures of supergiant stars range ...

. The star has about five or six times the

mass of the Sun The solar mass () is a frequently used unit of mass in astronomy, equal to approximately . It is approximately equal to the mass of the Sun. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies a ...

, but it has expanded to 48 times the

Sun's radius Solar radius is a unit of distance used to express the size of objects in astronomy relative to the Sun. The solar radius is usually defined as the radius to the layer in the Sun's photosphere where the optical depth equals 2/3: 1\,R_ = 6.957\ti ...

. It is most likely fusing helium into carbon in its core, and, with insufficient mass to explode as a

supernova A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last stellar evolution, evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion ...

, will likely end up as a massive

white dwarf A white dwarf is a Compact star, stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very density, dense: in an Earth sized volume, it packs a mass that is comparable to the Sun. No nuclear fusion takes place i ...

comparable to

Sirius B Sirius is the brightest star in the night sky. Its name is derived from the Greek word (Latin script: ), meaning 'glowing' or 'scorching'. The star is designated Canis Majoris, Latinized to Alpha Canis Majoris, and abbre ...

. It is emitting roughly 2,000 times the

Sun's luminosity The solar luminosity () is a unit of radiant flux ( power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxies and other celestial objects in terms of the output of the Sun. One nominal s ...

from its enlarged

photosphere The photosphere is a star's outer shell from which light is radiated. It extends into a star's surface until the plasma becomes opaque, equivalent to an optical depth of approximately , or equivalently, a depth from which 50% of light will esc ...

at an

effective temperature The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature ...

of 5,608 K, giving it the characteristic yellow hue of G-type stars. X-ray emissions from the

corona Corona (from the Latin for 'crown') most commonly refers to: * Stellar corona, the outer atmosphere of the Sun or another star * Corona (beer), a Mexican beer * Corona, informal term for the coronavirus or disease responsible for the COVID-19 ...

of this star have been detected using the

Chandra X-ray Observatory The Chandra X-ray Observatory (CXO), previously known as the Advanced X-ray Astrophysics Facility (AXAF), is a Flagship-class space telescope launched aboard the during STS-93 by NASA on July 23, 1999. Chandra is sensitive to X-ray sources ...

; among the first such detections of X-rays for a G-type supergiant. A secondary X-ray source discovered near Beta Aquarii probably has an extragalactic origin. This star belongs to a group of three intermediate mass stars with a space velocity that is carrying them perpendicular to the plane of the galaxy. The other members of this grouping are

Alpha Aquarii Alpha Aquarii is a yellow supergiant star in the constellation of Aquarius. Its identifier is a Bayer designation that is Latinized from α Aquarii, and is abbreviated Alf Aqr or α Aqr, respectively. This star has the of ...

and Eta Pegasi.

Optical companions

β Aquarii appears as a solitary star to the naked eye, but when viewed with a

telescope A telescope is a device used to observe distant objects by their emission, Absorption (electromagnetic radiation), absorption, or Reflection (physics), reflection of electromagnetic radiation. Originally, it was an optical instrument using len ...

is seen to have two faint optical companions. The first has an

of 11.0. In 1947, the

position angle In astronomy, position angle (usually abbreviated PA) is the convention for measuring angles on the sky. The International Astronomical Union defines it as the angle measured relative to the Celestial pole, north celestial pole (NCP), turning pos ...

was observed at 321 degrees with a separation from Beta Aquarii of 35.4

arcseconds A minute of arc, arcminute (abbreviated as arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of a degree. Since one degree is of a turn, or complete rotation, one arcminute is of a tu ...

. The second star has a magnitude of 11.6. Its position angle is 186 degrees with a separation from Beta Aquarii of 57.2

. The brighter star is designated component A of this grouping, while the companions are components B and C, respectively. As of 2008, there is no definitive evidence that the three stars form a ternary star system, and Gaia Data Release 2 shows the two companions to be around twice the distance of β Aquarii. All three stars have very different proper motions.

In mythology

In the context of older

worldviews A worldview (also world-view) or is said to be the fundamental cognitive orientation of an individual or society encompassing the whole of the individual's or society's knowledge, culture, and point of view. However, when two parties view the sa ...

(i.e.

Egyptian ''Egyptian'' describes something of, from, or related to Egypt. Egyptian or Egyptians may refer to: Nations and ethnic groups * Egyptians, a national group in North Africa ** Egyptian culture, a complex and stable culture with thousands of year ...

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 ...

and

Islamic mythology Islamic mythology is the body of myths associated with Islam and the Quran. Islam is a religion that is more concerned with social order and law than with religious rituals or myths. The primary focus of Islam is the practical and rational pra ...

), Sadalsuud relates to the rising of the Sun when winter has passed (March) and the season of gentle, continuous rain has begun. Hence the

myth Myth is a genre of folklore consisting primarily of narratives that play a fundamental role in a society. For scholars, this is very different from the vernacular usage of the term "myth" that refers to a belief that is not true. Instead, the ...

of ''"luck"'' or ''"good fortune"'' was seen as closely aligned with the essence of spring itself, the burgeoning of new life, and by extension agriculture, which in all societies is the very foundation of prosperity or ''"good fortune"''. This mythological view of ''"the luck of the lucks"'' also belongs to the 22d

Manzil For the convenience of those who read the Quran in a week the text may be divided into seven portions, each known as Manzil. The following division to 7 equal portions is by Hamzah az-Zaiyyat (d.156/772): # Al-Fatiha (chapter 1) through an-Ni ...

(Arabic Lunar Mansion), which included the two stars

Xi Aquarii Xi Aquarii is a binary star system in the equatorial constellation of Aquarius. Its name is a Bayer designation that is Latinized from ξ Aquarii, and abbreviated Xi Aqr or ξ Aqr. The system is visible to the naked eye as a point of ...

(Bunda) and 46 Capricorni. β and ξ Aquarii also constitute the Persian

lunar mansion Often called lunar mansion, a lunar station or lunar house is a segment of the ecliptic through which the Moon passes in orbit of the Moon, its orbit around the Earth. The concept was used by several ancient cultures as part of their calendrical ...

Bunda and the similar Coptic mansion Upuineuti, the meaning of which is ''"the Foundation"''. In Chinese mythology, β Aqr alone marks the xiu ( Chinese lunar mansion) Heu, Hiu, or Hü, ''" the Void/Emptiness"'', anciently Ko, the central one of seven xiu which, taken together, were known as Heung Wu, the Black Warrior, in the northern quarter of the sky. As such, Sadalsuud is an expression of the feminine

archetype The concept of an archetype ( ) appears in areas relating to behavior, historical psychology, philosophy and literary analysis. An archetype can be any of the following: # a statement, pattern of behavior, prototype, "first" form, or a main mo ...

, the Yin or ''"Void"'' (Cosmic Mother), from which, many cultures have believed, creation itself (birth) emanates.

Notes

References

External links

* An Atlas of the Universe
Multiple Star Orbits
* Harvard Map Collectio

Image β Aquarii
{{DEFAULTSORT:Beta Aquarii G-type supergiants Aquarius (constellation) Aquarii, Beta BD-06 5770 Aquarii, 022 204867 106278

8232 8 (eight) is the natural number following 7 and preceding 9. Etymology English ''eight'', from Old English '', æhta'', Proto-Germanic ''*ahto'' is a direct continuation of Proto-Indo-European '' *oḱtṓ(w)-'', and as such cognate wi ...

Sadalsuud Astronomical objects known since antiquity