Mintaka , designation Delta Orionis (δ Orionis, abbreviated Delta Ori, δ Ori) and 34 Orionis (34 Ori), is a quintuple

star system A star system or stellar system is a small number of stars that orbit each other, bound by gravity, gravitational attraction. It may sometimes be used to refer to a single star. A large group of stars bound by gravitation is generally calle ...

some 1,200

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

s 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 ...

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 Orion. Together with Alnitak (Zeta Orionis) and Alnilam (Epsilon Orionis), the three stars form

Orion's Belt Orion's Belt is an asterism in the constellation of Orion. Other names include the Belt of Orion, the Three Kings, and the Three Sisters. The belt consists of three bright and easily identifiable collinear star systems – Alnitak, Alnilam, ...

, known by many names among ancient cultures. The star is located very close to the

celestial equator The celestial equator is the great circle of the imaginary celestial sphere on the same plane as the equator of Earth. By extension, it is also a plane of reference in the equatorial coordinate system. Due to Earth's axial tilt, the celestial ...

. When Orion is near the meridian, Mintaka is the rightmost of the Belt's stars when viewed from the

Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the equator. For other planets in the Solar System, north is defined by humans as being in the same celestial sphere, celestial hemisphere relative to the invariable plane of the Solar ...

facing

south South is one of the cardinal directions or compass points. The direction is the opposite of north and is perpendicular to both west and east. Etymology The word ''south'' comes from Old English ''sūþ'', from earlier Proto-Germanic ''*sunþa ...

. The five stars form a hierarchy: * Delta Ori A ** Delta Ori Aa, an eclipsing binary with an orbital period of 5.7 days *** Delta Ori Aa1, a single star *** Delta Ori Aa2, a single star ** Delta Ori Ab, which orbits Aa at a distance, with an orbital period of 152 years * Delta Ori B, a single star not physically associated with the system * Delta Ori C, a binary star with an orbital period of 30 days, also known as HD 36485 ** Delta Ori Ca, a single star ** Delta Ori Cb, a single star "Mintaka" may also be used as the base name, e.g. "Mintaka C" for δ Ori C.

Nomenclature

''Delta Orionis'' is the star's

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 ...

, ''34 Orionis'' its Flamsteed designation. The name ''Mintaka'' itself is derived 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 ...

term for 'belt': منطقة or ''manṭaqa''. In 2016, 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 ...

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 ''Mintaka'' for this star. It is now so entered in the IAU Catalog of Star Names.

Observational history

Mintaka is the westernmost of the three stars of Orion's belt. It is easily visible to the naked eye, one of the brightest stars in the sky, and has been known since antiquity.

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 ...

measurements taken by Henri-Alexandre Deslandres in 1900 at

Paris Observatory The Paris Observatory (, ), a research institution of the Paris Sciences et Lettres University, is the foremost astronomical observatory of France, and one of the largest astronomical centres in the world. Its historic building is on the Left Ban ...

showed that Mintaka had a variable radial velocity and therefore was a

spectroscopic binary A binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved as separate stars us ...

. His preliminary

orbital period The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets ...

estimate of 1.92 days was shown to be incorrect in 1904 when Johannes Franz Hartmann using photographic plates taken at Potsdam Observatory showed that the orbital period was 5.7 days. Hartmann also noticed that the calcium K line at 393.4 nanometres in the

stellar spectrum Astronomical spectroscopy is the study of astronomy using the techniques of spectroscopy to measure the spectrum of electromagnetic radiation, including visible light, ultraviolet, X-ray, infrared and radio waves that radiate from stars and oth ...

did not share in the periodic displacements of the lines due to orbital motion of the star and theorized that there was a cloud in the line of sight to Mintaka that contained

calcium Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to it ...

. This was the first detection of the

interstellar medium The interstellar medium (ISM) is the matter and radiation that exists in the outer space, space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, as well as cosmic dust, dust and cosmic rays. It f ...

System

Hierarchy of orbits in the system

δ Orionis is a

multiple star system A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction. It may sometimes be used to refer to a single star. A large group of stars bound by gravitation is generally called a ''st ...

. There is a

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 ...

7 star about 52

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 ...

away from the second-magnitude primary and a much fainter star in between. The system is designated WDS 05320-0018 in 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 January 2024) 1 ...

, with the 14th-magnitude companion listed as component B and the seventh-magnitude star as component C. The primary component is itself a triple system: a class-O9.5 bright giant and a class-B

main-sequence star In astronomy, the main sequence is a classification of stars which appear on plots of stellar color versus brightness as a continuous and distinctive band. Stars on this band are known as main-sequence stars or dwarf stars, and positions of star ...

orbit every 5.73 days and exhibit shallow eclipses when the star dims about 0.2 of a magnitude, and a B-class

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 ...

is resolved 0.26" away. At the primary eclipse, the apparent magnitude (of the whole system) drops from 2.23 to 2.35, while it only drops to 2.29 at the secondary eclipse. The outer star of the triple system orbits the inner pair once every . The orbit is quite eccentric, with the separation varying between and . The seventh-magnitude companion, HD 36485, is a chemically peculiar

B-type main-sequence star A B-type main-sequence star (B V) is a main-sequence (hydrogen-burning) star of spectral type B and luminosity class V. These stars have from 2 to 16 times the mass of the Sun and surface temperatures between 10,000 and 30,000 K. B-type stars ...

and itself a spectroscopic binary with a faint A-type companion in a 30-day orbit. It has an unusual spectrum with

H-alpha Hydrogen-alpha, typically shortened to H-alpha or Hα, is a deep-red visible spectral line of the hydrogen atom with a wavelength of 656.28 nm in air and 656.46 nm in vacuum. It is the first spectral line in the Balmer series and is em ...

emission and unusually strong helium

absorption line Absorption spectroscopy is spectroscopy that involves techniques that measure the absorption (electromagnetic radiation), absorption of electromagnetic radiation, as a function of frequency or wavelength, due to its interaction with a sample. Th ...

s. It has a strong magnetic field and a very slow rotational velocity that produces chemical stratification in its atmosphere, which leads to the unusual abundances seen in the spectrum. The 14th-magnitude companion, δ Orionis B, is thought to be closer than the rest of the system and not physically associated with it. It is likely to be a K-type main sequence star. Mintaka is surrounded by a cluster of faint stars, possibly part of the cluster surrounding σ Ori.

Distance

The distance derived from 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 ...

'' satellite parallax is , while spectroscopic distances, comparisons to similar stars, and cluster membership all suggest a value more than double that. This type of unreconcilable discrepancy is not unique to Mintaka and the reasons for it have yet to be clarified. In Gaia Data Release 3, component C is listed with a parallax of , consistent with the distances derived by other methods but disagreeing with the ''Hipparcos''-derived value for the primary. The Gaia DR3 parallax for component B is , strongly suggesting it is considerably closer than the other members of the system and merely a chance alignment. At that distance it is likely to be a K-type main sequence star.

Etymology and cultural significance

Mintaka was seen by astrologers as a portent of good fortune.

Orion's Belt

The three belt stars were collectively known by many names in many cultures. Arabic terms include ''Al Nijād'' 'the Belt', ''Al Nasak'' 'the Line', ''Al Alkāt'' 'the Golden Grains or Nuts', and, in modern Arabic, ''Al Mīzān al Ḥakk'' 'the Accurate Scale Beam'. In

Chinese mythology Chinese mythology () is mythology that has been passed down in oral form or recorded in literature throughout the area now known as Greater China. Chinese mythology encompasses a diverse array of myths derived from regional and cultural tradit ...

, they were also known as the Weighing Beam. In Chinese, (), meaning '' Three Stars (asterism)'', refers to an asterism consisting of Mintaka, Alnilam, and Alnitak (Orion's Belt), with

Betelgeuse Betelgeuse is a red supergiant star in the constellation of Orion (constellation), Orion. It is usually the List of brightest stars, tenth-brightest star in the night sky and, after Rigel, the second brightest in its constellation. It i ...

, Bellatrix, Saiph and

Rigel Rigel is a blue supergiant star in the constellation of Orion. It has the Bayer designation β Orionis, which is Latinized to Beta Orionis and abbreviated Beta Ori or β Ori. Rigel is the brightest and most massive componentand ...

later added. 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 Mintaka is (, ).
AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 25 日
It is one of the western mansions of the White Tiger.

Namesakes

The USS ''Mintaka'' (AK-94) was a

United States Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...

''Crater''-class cargo ship named after the star.

References

External links

*
Mintaka page constellationsofwords.com

Mintaka page at Astrostudio

Mintaka with HD 36485 visible at 12 noon and star C at 4 o'clock
{{DEFAULTSORT:Mintaka Orionis, Delta Spectroscopic binaries Eclipsing binaries O-type bright giants B-type main-sequence stars Orion (constellation) Orionis, 34

1851 Events January–March * January 11 – Hong Xiuquan officially begins the Taiping Rebellion in China, one of the bloodiest revolts that would lead to 20 million deaths. * January 15 – Christian Female College, modern-d ...

036486 Triple star systems BD-00 0983 025930 Mintaka