Alcyone , designated η Tauri (Eta Tauri, abbreviated Eta Tau, η Tau), is a

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 Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Taurus Taurus is Latin for 'bull' and may refer to: * Taurus (astrology), the astrological sign * Taurus (constellation), one of the constellations of the zodiac * Taurus (mythology), one of two Greek mythological characters named Taurus * ''Bos taurus ...

. Approximately 440

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 from the Sun, it is the brightest

in the

Pleiades The Pleiades (), also known as The Seven Sisters, Messier 45 and other names by different cultures, is an asterism and an open star cluster containing middle-aged, hot B-type stars in the north-west of the constellation Taurus. At a distance of ...

open cluster An open cluster is a type of star cluster made of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way galaxy, and ...

, which is a young cluster, around 100 million years old. There are a number of fainter stars very close to Alcyone, some of which are members of the same cluster.

Nomenclature

''Eta Tauri'' 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. ...

. The name ''Alcyone'' originates in

Greek mythology A major branch of classical mythology, Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the Cosmogony, origin and Cosmology#Metaphysical co ...

; she is one of the seven daughters of

Atlas An atlas is a collection of maps; it is typically a bundle of maps of Earth or of a region of Earth. Atlases have traditionally been bound into book form, but today many atlases are in multimedia formats. In addition to presenting geographic ...

and Pleione known as

the Pleiades The Pleiades (), also known as The Seven Sisters, Messier 45 and other names by different cultures, is an asterism and an open star cluster containing middle-aged, hot B-type stars in the north-west of the constellation Taurus. At a distance of ...

. In 2016, 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) 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 catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included ''Alcyone'' for this star. It is now so entered in the IAU Catalog of Star Names. 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 va ...

, (), meaning ''

Hairy Head The Hairy Head mansion (昴宿, pinyin: Mǎo Xiù) is one of the Twenty-eight mansions of the Chinese constellations. It is one of the western mansions of the White Tiger. This mansion corresponds to the Pleiades The Pleiades (), also kno ...

'', refers to an asterism consisting Alcyone,

Electra Electra (; grc, Ήλέκτρα) is one of the most popular mythological characters in tragedies.Evans (1970), p. 79 She is the main character in two Greek tragedies, '' Electra'' by Sophocles and '' Electra'' by Euripides. She is also the centra ...

, Taygeta, Asterope,

Maia Maia (; Ancient Greek: Μαῖα; also spelled Maie, ; la, Maia), in ancient Greek religion and mythology, is one of the Pleiades and the mother of Hermes, one of the major Greek gods, by Zeus, the king of Olympus. Family Maia is the daugh ...

, Merope, and

. Consequently, the Chinese name for Alcyone itself is (), "the Sixth Star of Hairy Head".

Physical Properties

Alcyone Is a blue-white B-type giant, similar the other bright B-type stars in the Pleiades cluster. 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 li ...

of +2.87 (

absolute magnitude Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse Logarithmic scale, logarithmic Magnitude (astronomy), astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent mag ...

= −2.39), it is the brightest and most luminous star in the Pleiades. The spectral type of B7IIIe indicates that

emission lines A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to iden ...

are present in its

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 i ...

. Like many

Be star Be stars are a heterogeneous set of stars with B spectral types and emission lines. A narrower definition, sometimes referred to as ''classical Be stars'', is a non-supergiant B star whose spectrum has, or had at some time, one or more Balmer e ...

s, Alcyone has created a gaseous disk flung into orbit around the star from its equator. Alcyone has a high rotational velocity, which causes it to have an ellipsoidal shape. Its effective radius is almost ten times that of the Sun, but the actual radius is lesser at poles and greater at the equator. Its

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 ...

is approximately 12,300 K, with the actual temperature being greater at the poles and lesser at the equator. Its bolometric luminosity is 2,030 times

solar Solar may refer to: Astronomy * Of or relating to the Sun ** Solar telescope, a special purpose telescope used to observe the Sun ** A device that utilizes solar energy (e.g. "solar panels") ** Solar calendar, a calendar whose dates indicate t ...

Companions

The

Catalog of Components of Double and Multiple Stars The Catalog of Components of Double and Multiple Stars, or CCDM, is an astrometric star catalogue of double and multiple stars. It was made by Jean Dommanget and Omer Nys at the Royal Observatory of Belgium in order to provide an input catalogu ...

lists three companions: B is

24 Tauri 4 (four) is a number, numeral and digit. It is the natural number following 3 and preceding 5. It is the smallest semiprime and composite number, and is considered unlucky in many East Asian cultures. In mathematics Four is the smallest co ...

, a magnitude 6.28 A0 main-sequence star 117" away; C is V647 Tauri, a δ Sct variable star; and D is a magnitude 9.15 F3 main-sequence star. V647 Tau varies from magnitude +8.25 to +8.30 over 1.13 hours. The

Washington Double Star Catalog The Washington Double Star Catalog, or WDS, is a catalog of double stars, maintained at the United States Naval Observatory. The catalog contains positions, magnitudes, proper motions and spectral types and has entries for (as of June 2017) 141,7 ...

lists a further four companions, all fainter than 11th magnitude, and also describes component D as itself double with two nearly equal components separated by 0.30". Some previous lunar occultation studies found evidence of sub-arcsound companions, but more recently, a 2021 interferometric study concluded that Alcyone is a single star system.

References

External links

* Jim Kaler's Stars, University of Illinoi
ALCYONE (Eta Tauri)

{{DEFAULTSORT:Alcyone (star) Tauri, Eta Taurus (constellation) B-type giants A-type main-sequence stars F-type main-sequence stars Eclipsing binaries 5 Delta Scuti variables Pleiades Open Cluster

Alcyone In Greek mythology, Alcyone or Halcyone (; grc, Ἀλκυόνη, Alkyónē derived from grc, ἀλκυών, alkyṓn, kingfisher, label=none) and Ceyx (; grc, Κήϋξ, Kḗÿx) were a wife and husband who incurred the wrath of the god Zeus ...

Tauri, 025 017702

1165 Year 1165 (Roman numerals, MCLXV) was a common year starting on Friday (link will display the full calendar) of the Julian calendar. Events By place Byzantine Empire * Spring – Emperor Manuel I Komnenos, Manuel I (Komnenos) mak ...

023630 BD+23 0541

Nomenclature

Physical Properties

Companions

See also

References

External links