Mintaka
Template:Short description {{#invoke:other uses|otheruses}} Template:Starbox begin Template:Starbox image Template:Starbox observe 3s Template:Starbox character Template:Starbox astrometry Template:Starbox astrometry Template:Starbox astrometry Template:Starbox astrometry Template:Starbox astrometry Template:Starbox orbit Template:Starbox orbit Template:Starbox detail Template:Starbox detail Template:Starbox detail Template:Starbox catalog Template:Starbox reference Template:Starbox end
Mintaka Template:IPAc-en,<ref name=Rumrill>Template:Cite journal</ref> designation Delta Orionis (δ Orionis, abbreviated Delta Ori, δ Ori) and 34 Orionis (34 Ori), is a quintuple star system some 1,200 light-years from the Sun in the constellation of Orion. Together with Alnitak (Zeta Orionis) and Alnilam (Epsilon Orionis), the three stars form Orion's Belt, known by many names among ancient cultures. The star is located very close to the celestial equator. When Orion is near the meridian, Mintaka is the rightmost of the Belt's stars when viewed from the Northern Hemisphere facing south.
The five stars form a hierarchy:<ref name=oplistilova2023/>
- 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 Aa, an eclipsing binary with an orbital period of 5.7 days
- 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.
NomenclatureEdit
Delta Orionis is the star's Bayer designation, 34 Orionis its Flamsteed designation. The name Mintaka itself is derived from an Arabic term for 'belt': منطقة or manṭaqa.<ref name=allen>Template:Cite book</ref> In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)<ref name="WGSN">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016<ref name="WGSN1">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> 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.<ref name="IAU-CSN">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Observational historyEdit
Template:Location mark 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 in 1900 at Paris Observatory showed that Mintaka had a variable radial velocity and therefore was a spectroscopic binary.<ref name="Deslandres1900"/> His preliminary orbital period 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.<ref name="Hartmann1904"/> Hartmann also noticed that the calcium K line 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. This was the first detection of the interstellar medium.<ref name="Hartmann1904"/> Template:Clear left
SystemEdit
Template:Chart/start Template:Chart Template:Chart Template:Chart Template:Chart Template:Chart Template:Chart Template:Chart Template:Chart Template:Chart Template:Chart/end Hierarchy of orbits in the system<ref name=oplistilova2023/>
Template:Stack end δ Orionis is a multiple star system. There is a magnitude 7 star about 52 arcseconds 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, with the 14th-magnitude companion listed as component B and the seventh-magnitude star as component C.<ref name=wds>Template:Cite journal</ref>
The primary component is itself a triple system: a class-O9.5 bright giant and a class-B main-sequence star orbit every 5.73 days and exhibit shallow eclipses when the star dims about 0.2 of a magnitude,<ref name=gcvs>Template:Cite journal</ref> and a B-class subgiant is resolved 0.26" away.<ref name=tokovinin1997>Template:Cite journal</ref> 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.<ref name=zasche>Template:Cite journal</ref>
The outer star of the triple system orbits the inner pair once every Template:Convert. The orbit is quite eccentric, with the separation varying between Template:Convert and Template:Convert.<ref name=oplistilova2023/>
The seventh-magnitude companion, HD 36485, is a chemically peculiar B-type main-sequence 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 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.<ref name=leone2010>Template:Cite journal</ref>
The 14th-magnitude companion, δ Orionis B, is thought to be closer than the rest of the system and not physically associated with it.<ref name=dr3b/> It is likely to be a K-type main sequence star.<ref name=oplistilova2023/>
Mintaka is surrounded by a cluster of faint stars, possibly part of the cluster surrounding σ Ori.<ref name="CaballeroSolano2008">Template:Cite journal</ref>
DistanceEdit
The distance derived from the Hipparcos satellite parallax is Template:Val,<ref name="van Leeuwen2007"/> while spectroscopic distances, comparisons to similar stars, and cluster membership all suggest a value more than double that.<ref name="CorcoranNichols2015">Template:Cite journal</ref> This type of unreconcilable discrepancy is not unique to Mintaka and the reasons for it have yet to be clarified.<ref name=shenar2015/> In Gaia Data Release 3, component C is listed with a parallax of Template:Val,<ref name=dr3c/> consistent with the distances derived by other methods but disagreeing with the Hipparcos-derived value for the primary.<ref name="van Leeuwen2007"/>
The Gaia DR3 parallax for component B is Template:Val, strongly suggesting it is considerably closer than the other members of the system and merely a chance alignment.<ref name=dr3b>Template:Cite Gaia DR3</ref> At that distance it is likely to be a K-type main sequence star.<ref name=oplistilova2023/>
Etymology and cultural significanceEdit
Mintaka was seen by astrologers as a portent of good fortune.<ref name=allen/>
Orion's BeltEdit
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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, they were also known as the Weighing Beam.Template:Cn
In Chinese, {{#invoke:Lang|lang}} ({{#invoke:Lang|lang}}), meaning Three Stars (asterism), refers to an asterism consisting of Mintaka, Alnilam, and Alnitak (Orion's Belt), with Betelgeuse, Bellatrix, Saiph and Rigel later added.<ref>Template:In lang 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, Template:ISBN</ref> Consequently, the Chinese name for Mintaka is {{#invoke:Lang|lang}} ({{#invoke:Lang|lang}}, Template:Langx).<ref>Template:In lang AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 25 日 Template:Webarchive</ref> It is one of the western mansions of the White Tiger. Template:Clear left
NamesakesEdit
The USS Mintaka (AK-94) was a United States Navy Crater-class cargo ship named after the star.