For other uses, see Mintaka (disambiguation).

Mintaka /mInt@k@/,[1] 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 away 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:[2]

  • Delta Ori A
    • Delta Ori Aa, an eclipsing binary with an orbital period of 5.7 days
      • Delta Ori Aa1
      • Delta Ori Aa2
    • Delta Ori Ab, which orbits Aa with an orbital period of 152 years
  • Delta Ori C, a binary star with an orbital period of 30 days, also known as HD 36485
    • Delta Ori Ca
    • Delta Ori Cb

All five stars are hot and luminous, more massive than the Sun.

Nomenclature

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.[3] In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[4] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[5] 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.[6]

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.[7] 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.[8] 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.[8]

System

Hierarchy of orbits in the system[2]

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.[9]

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,[10] and a B-class subgiant is resolved 0.26" away.[11] 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.[12]

The outer star of the triple system orbits the inner pair once every 53,839 days. The orbit is quite eccentric, with the separation varying between 8,244 solar radius and 31,832 solar radius.[2] This star is generally referred to as component Ab,[11] but some catalogues list it as component D, for example CCDM J05320-0018D.

The seventh-magnitude companion, δ Ori C, also known as 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.[13]

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.[14] It is likely to be a K-type main sequence star.[2]

Mintaka is surrounded by a cluster of faint stars, possibly part of the cluster surrounding σ Ori.[15]

Distance

The distance derived from the Hipparcos satellite parallax is 212 ± 30 parsecs,[16] while spectroscopic distances, comparisons to similar stars, and cluster membership all suggest a value more than double that.[17] This type of unreconcilable discrepancy is not unique to Mintaka and the reasons for it have yet to be clarified.[18] In Gaia Data Release 3, component C is listed with a parallax of 2.6245 ± 0.0538 mas,[19] consistent with the distances derived by other methods but disagreeing with the Hipparcos-derived value for the primary.[16]

The Gaia DR3 parallax for component B is 3.5002 ± 0.0119 ", strongly suggesting it is considerably closer than the other members of the system and merely a chance alignment.[14] At that distance it is likely to be a K-type main sequence star.[2]

Etymology and cultural significance

Mintaka was seen by astrologers as a portent of good fortune.[3]

Orion's Belt

Main article: 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, they were also known as the Weighing Beam.[citation needed]

In Chinese, 參宿 (Shēn Xiù), 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.[20] Consequently, the Chinese name for Mintaka is 參宿三 (Shēn Xiù Sān, English: the Third Star of Three Stars).[21] 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

  1. ^ Rumrill, H. B. (June 1936). "Star Name Pronunciation". Publications of the Astronomical Society of the Pacific. 48 (283): 139. Bibcode:1936PASP...48..139R. doi:10.1086/124681. S2CID 120743052
  2. ^ Oplištilová, A.; Mayer, P.; Harmanec, P.; Brož, M.; Pigulski, A.; Božić, H.; Zasche, P.; Šlechta, M.; Pablo, H.; Kołaczek-Szymański, P. A.; Moffat, A. F. J.; Lovekin, C. C.; Wade, G. A.; Zwintz, K.; Popowicz, A.; Weiss, W. W. (2023). "Spectrum of the secondary component and new orbital elements of the massive triple star δ Ori A". Astronomy and Astrophysics. 672: A31. arXiv:2301.10290. Bibcode:2023A&A...672A..31O. doi:10.1051/0004-6361/202245272. S2CID 256226821
  3. ^ Allen, Richard Hinckley (1963 [1899]). Star-names and their meanings. New York, NY: Dover Publications. p. 314. ISBN 1-931559-44-9.
  4. ^ "IAU Working Group on Star Names (WGSN)". Archived from the original on 10 June 2016. Retrieved 22 May 2016.
  5. ^ "Bulletin of the IAU Working Group on Star Names, No. 1". Retrieved 28 July 2016.
  6. ^ "IAU Catalog of Star Names". Retrieved 28 July 2016.
  7. ^ Deslandres, H. (1900). "Variable velocity in line of sight of delta Orionis. (Notes)". The Observatory. 23: 148. Bibcode:1900Obs....23..148D
  8. ^ Hartmann, J. (1904). "Investigations on the spectrum and orbit of delta Orionis". Astrophysical Journal. 19: 268–286. Bibcode:1904ApJ....19..268H. doi:10.1086/141112
  9. ^ Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466. Bibcode:2001AJ....122.3466M. doi:10.1086/323920
  10. ^ Samus, N. N. & Durlevich, O. V. et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007–2013)". VizieR On-line Data Catalog: B/gcvs. Bibcode:2009yCat....102025S
  11. ^ Tokovinin, A. A. (1997). "MSC - a catalogue of physical multiple stars". Astronomy and Astrophysics Supplement Series. 124: 75–84. Bibcode:1997A&AS..124...75T. doi:10.1051/aas:1997181
  12. ^ Zasche, P.; Wolf, M.; Hartkopf, W. I.; Svoboda, P.; Uhlař, R.; Liakos, A.; Gazeas, K. (2009). "A Catalog of Visual Double and Multiple Stars with Eclipsing Components". Astronomical Journal. 138 (2): 664. arXiv:0907.5172. Bibcode:2009AJ....138..664Z. doi:10.1088/0004-6256/138/2/664. S2CID 17089387
  13. ^ Leone, F.; Bohlender, D. A.; Bolton, C. T.; Buemi, C.; Catanzaro, G.; Hill, G. M.; Stift, M. J. (2010). "The magnetic field and circumstellar environment of the helium-strong star HD36485 = δ Ori C". Monthly Notices of the Royal Astronomical Society. 401 (4): 2739. Bibcode:2010MNRAS.401.2739L. doi:10.1111/j.1365-2966.2009.15858.x
  14. ^
  15. ^ Caballero, J. A. & Solano, E. (2008). "Young stars and brown dwarfs surrounding Alnilam (ɛ Orionis) and Mintaka (δ Orionis)". Astronomy and Astrophysics. 485 (3): 931. arXiv:0804.2184. Bibcode:2008A&A...485..931C. doi:10.1051/0004-6361:200809595. S2CID 16175953
  16. ^ van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600 Vizier catalog entry
  17. ^ Corcoran, M. F.; Nichols, J. S.; Pablo, H.; Shenar, T.; Pollock, A. M. T.; Waldron, W. L.; Moffat, A. F. J.; Richardson, N. D.; Russell, C. M. P.; Hamaguchi, K.; Huenemoerder, D. P.; Oskinova, L.; Hamann, W.-R.; Nazé, Y.; Ignace, R.; Evans, N. R.; Lomax, J. R.; Hoffman, J. L.; Gayley, K.; Owocki, S. P.; Leutenegger, M.; Gull, T. R.; Hole, K. T.; Lauer, J.; Iping, R. C. (2015). "A Coordinated X-Ray and Optical Campaign of the Nearest Massive Eclipsing Binary, δ Orionis Aa. I. Overview of the X-Ray Spectrum". Astrophysical Journal. 809 (2): 132. arXiv:1507.05101. Bibcode:2015ApJ...809..132C. doi:10.1088/0004-637X/809/2/132. S2CID 17339779
  18. ^ Shenar, T.; Oskinova, L.; Hamann, W.-R.; Corcoran, M. F.; Moffat, A. F. J.; Pablo, H.; Richardson, N. D.; Waldron, W. L.; Huenemoerder, D. P.; Maíz Apellániz, J.; Nichols, J. S.; Todt, H.; Nazé, Y.; Hoffman, J. L.; Pollock, A. M. T.; Negueruela, I. (2015). "A Coordinated X-Ray and Optical Campaign of the Nearest Massive Eclipsing Binary, δ Orionis Aa. IV. A Multiwavelength, Non-LTE Spectroscopic Analysis". Astrophysical Journal. 809 (2): 135. arXiv:1503.03476. Bibcode:2015ApJ...809..135S. doi:10.1088/0004-637X/809/2/135. hdl:10045/59172. S2CID 14909574
  19. ^
  20. ^ (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7
  21. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 25 日 Archived 2011-07-16 at the Wayback Machine