Mintaka

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. In 2016, the International Astronomical Union organized a Working Group on Star Names (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 in 1900 at Paris Observatory showed that Mintaka had a variable radial velocity and therefore was a spectroscopic binary. 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. 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. ==System==

Hierarchy of orbits in the system 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, and a B-class subgiant 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 14th-magnitude optical companion, δ Orionis B, is thought to be closer than the rest of the system and not physically associated with it. ==Distance==

The distance derived from the Hipparcos satellite parallax is , This type of unreconcilable discrepancy is not unique to Mintaka and the reasons for it have yet to be clarified. 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. Consequently, the Chinese name for Mintaka is (, ). It is one of the western mansions of the White Tiger. ==Namesakes==

The USS Mintaka (AK-94) was a United States Navy Crater-class cargo ship named after the star. ==References==