Beta Aquarii is a single

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the earliest constellation ...

Aquarius Aquarius may refer to: Astrology * Aquarius (astrology), an astrological sign * Age of Aquarius, a time period in the cycle of astrological ages Astronomy * Aquarius (constellation) * Aquarius in Chinese astronomy Arts and entertainment ...

. It has the official name Sadalsuud (), and sometimes is identified as 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 lines of sight and is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby object ...

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 of celestial ob ...

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

light year 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 ...

s (165 parsecs) 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 further away with a

radial velocity The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the rate of change of the distance or range between the two points. It is equivalent to the vector projection ...

of 6.5 km/s. The star serves as an IAU radial velocity standard.

Nomenclature

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

Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek or Latin letter followed by the genitive form of its parent constellation's Latin name. The original list of Bayer designations contained 1,564 stars ...

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

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 ...

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 a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...

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; 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 ...

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 and apathy. Feelings of emptiness often accompany dysthymia, depression, loneliness, anhedonia, despair, or other mental/emotional disorders, including schizoid ...

(asterism)'', refers to an asterism consisting of Beta Aquarii and Alpha Equulei. 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 Aquarii itself is (, en, the First Star of Emptiness). ''Sadalsuud'' is found in

Hindu Hindus (; ) are people who religiously adhere to Hinduism. Jeffery D. Long (2007), A Vision for Hinduism, IB Tauris, , pages 35–37 Historically, the term has also been used as a geographical, cultural, and later religious identifier for ...

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

Nakshatra Nakshatra ( sa, नक्षत्रम्, translit=Nakṣatram) is the term for lunar mansion in Hindu astrology and Indian Astronomy. A nakshatra is one of 27 (sometimes also 28) sectors along the ecliptic. Their names are related to a ...

Shravishthā, a lunar mansion which is ruled by Eight vasus - the ''"deities of earthly abundance"'' . On the

Euphrates The Euphrates () is the longest and one of the most historically important rivers of Western Asia. Tigris–Euphrates river system, Together with the Tigris, it is one of the two defining rivers of Mesopotamia ( ''the land between the rivers'') ...

, ''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' 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 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 ...

of 2.87 and a

stellar classification 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 ...

of G0 Ib. 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. It has an estimated age of 60 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 temperature range of supergiant stars spa ...

. The star has about five times the

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

, but it has expanded to 48 times the Sun's radius. 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 ...

from its enlarged

photosphere The photosphere is a star's outer shell from which light is radiated. The term itself is derived from Ancient Greek roots, φῶς, φωτός/''phos, photos'' meaning "light" and σφαῖρα/''sphaira'' meaning "sphere", in reference to it ...

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 SARS-CoV-2, which causes the COVID-19 di ...

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 and

Eta Pegasi Eta Pegasi or η Pegasi, formally named Matar , is a binary star in the constellation of Pegasus. The apparent visual magnitude of this star is +2.95, making it the fifth-brightest member of Pegasus. Based upon parallax measurements, ...

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, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to obse ...

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 north celestial pole (NCP), turning positive into the ...

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

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

. 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 The ''Gaia'' catalogues are star catalogues created using the results obtained by ''Gaia'' space telescope. The catalogues are released in stages that will contain increasing amounts of information; the early releases also miss some stars, especi ...

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 (i.e. Egyptian, Persian 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 ritual or myths. ''The Oxford Companion to World Mythology'' identifies a numbe ...

), 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 folklore genre consisting of narratives that play a fundamental role in a society, such as foundational tales or origin myths. Since "myth" is widely used to imply that a story is not objectively true, the identification of a narrat ...

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 (Arabic Lunar Mansion), which included the two stars

Xi Aquarii Xi Aquarii (ξ Aquarii, abbreviated Xi Aqr, ξ Aqr) is a binary star system in the equatorial constellation of Aquarius. It is visible to the naked eye with an apparent visual magnitude of 4.7. Based upon parallax measurements made du ...

(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 its orbit around the Earth. The concept was used by several ancient cultures as part of their calendrical system. Stations ...

Bunda and the similar Coptic mansion Upuineuti, the meaning of which is ''"the Foundation"''. In Chinese mythology, β Aqr alone marks the sieu (Chinese Lunar Mansion) Heu, Hiu, or Hü, ''"the Void"'', anciently Ko, the central one of the seven sieu 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, and literary analysis. An archetype can be any of the following: # a statement, pattern of behavior, prototype, "first" form, or a main model that ...

, the

Yin Yin may refer to: *the dark force in the yin and yang from traditional Chinese philosophy and medicine *Yīn (surname) (), a Chinese surname *Yǐn (surname) (), a Chinese surname *Shang dynasty, also known as the Yin dynasty **Yinxu or Yin, the S ...

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) Astronomical objects known since antiquity Aquarii, Beta BD-06 5770 Aquarii, 022 204867 106278

8232 8 (eight) is the natural number following 7 and preceding 9. In mathematics 8 is: * a composite number, its proper divisors being , , and . It is twice 4 or four times 2. * a power of two, being 2 (two cubed), and is the first number of ...

Sadalsuud