Mintaka , designation Delta Orionis (δ Orionis, abbreviated Delta Ori, δ Ori) and 34 Orionis (34 Ori), is a multiple star system some 1,200 light-years 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 ...

in the constellation of Orion. Together with

Alnitak Alnitak is a triple star system in the constellation of Orion. It has the designations ζ Orionis, which is Latinised to Zeta Orionis and abbreviated Zeta Ori or ζ Ori, and 50 Orionis, abbreviated 50 Ori. The system is located at a ...

(Zeta Orionis) and

Alnilam Alnilam is the central star of Orion's Belt in the equatorial constellation of Orion. It has the Bayer designation ε Orionis, which is Latinised to Epsilon Orionis and abbreviated Epsilon Ori or ε Ori. This is a massive, blue supe ...

(Epsilon Orionis), the three stars form

Orion's Belt Orion's Belt or the Belt of Orion, also known as the Three Kings or Three Sisters, is an asterism in the constellation Orion. It consists of the three bright stars Alnitak, Alnilam and Mintaka. Looking for Orion's Belt is the easiest way to ...

, 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. This plane of reference bases the equatorial coordinate system. In other words, the celestial equator is an abstract proj ...

. When Orion is near the

meridian Meridian or a meridian line (from Latin ''meridies'' via Old French ''meridiane'', meaning “midday”) may refer to Science * Meridian (astronomy), imaginary circle in a plane perpendicular to the planes of the celestial equator and horizon * ...

, Mintaka is the rightmost of the Belt's stars when viewed from the Northern Hemisphere facing south.

Nomenclature

''Delta Orionis'' is the star's Bayer designation, ''34 Orionis'' its

Flamsteed designation A Flamsteed designation is a combination of a number and constellation name that uniquely identifies most naked eye stars in the modern constellations visible from southern England. They are named for John Flamsteed who first used them while co ...

. The name ''Mintaka'' itself is derived 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 ...

term for 'belt': منطقة or ''manṭaqa''. 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 ...

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 measurements taken by

Henri-Alexandre Deslandres Henri Alexandre Deslandres (24 July 1853 – 15 January 1948) was a French astronomer, director of the Meudon and Paris Observatories, who carried out intensive studies on the behaviour of the atmosphere of the Sun. Biography Deslandres' un ...

in 1900 at Paris Observatory showed that Mintaka had a variable radial velocity and therefore was a spectroscopic binary. 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 Johannes Franz Hartmann (11 January 1865 – 13 September 1936) was a German physicist and astronomer. In 1904, while studying the spectroscopy of Delta Orionis he noticed that most of the spectrum had a shift, except the calcium lines, which h ...

using photographic plates taken at Potsdam Observatory showed that the orbital period was 5.7 days. Hartmann also noticed that the

calcium K line In physics and optics, the Fraunhofer lines are a set of spectral absorption lines named after the German physicist Joseph von Fraunhofer (1787–1826). The lines were originally observed as dark features (absorption lines) in the optical spectru ...

at 393.4 nanometres in the stellar spectrum 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 with the 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 t ...

. This was the first detection of the interstellar medium.

System

δ Orionis is a multiple star system. 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 (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 ...

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 June 2017) 141, ...

, 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 continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hert ...

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 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 star ...

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

H-alpha H-alpha (Hα) is a specific deep-red visible spectral line 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 wit ...

emission and unusually strong helium absorption lines. 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 is thought to be around the same distance and is a somewhat cooler and less luminous star than the Sun. Mintaka is surrounded by a cluster of faint stars, possibly part of the cluster surrounding σ Ori.

Distance

The distance derived from the '' Hipparcos'' 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 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, espec ...

, components B and C are listed with parallaxes of and , respectively, implying distances considerably further than the ''Hipparcos''-derived value for the primary.

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 in the geographic area now known as Greater China. Chinese mythology includes many varied myths from regional and cultural traditions. Much of t ...

, they were also known as the Weighing Beam. 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 '' Three Stars (asterism)'', refers to an asterism consisting of Mintaka,

, and

(Orion's Belt), with Betelgeuse, Bellatrix,

Saiph Saiph , designation Kappa Orionis (κ Orionis, abbreviated Kappa Ori, κ Ori) and 53 Orionis (53 Ori), is the sixth-brightest star in the constellation of Orion. Of the four bright stars that compose Orion's main quadrangle, it is the sta ...

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 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 Mintaka is (, en, the Third Star of Three Stars).
AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 25 日
/ref> It is one of the western mansions of the

White Tiger The white tiger or bleached tiger is a leucistic pigmentation variant of the Mainland tiger. It is reported in the wild from time to time in the Indian states of Madhya Pradesh, Assam, West Bengal, Bihar, Odisha, in the Sunderbans region and ...

Namesakes

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

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

''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) Stars named from the Arabic language Orionis, 34 1851 036486 Triple star systems Durchmusterung objects 025930