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Iota Hydrae

In today's article, we will explore the fascinating world of Iota Hydrae. From its origins to its impact on modern society, we will delve into its history, evolution and relevance in today's world. Iota Hydrae is a topic that has aroused interest and curiosity over time, and throughout this article, we will try to shed light on its most significant aspects. With expert interviews, in-depth analysis and practical examples, we aim to offer a comprehensive and insightful view of Iota Hydrae, so that our readers can expand their knowledge and better understand its importance in different contexts. Get ready to enter a world of discoveries and reflections on Iota Hydrae!

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Iota Hydrae
Location of Iota Hydrae (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Hydra
Right ascension 09h 39m 51.36145s[1]
Declination −01° 08′ 34.1135″[1]
Apparent magnitude (V) 3.91[2]
Characteristics
Spectral type K2.5 III[2]
B−V color index 1.32
Variable type Suspected[3]
Astrometry
Radial velocity (Rv)+24.19±0.36[4] km/s
Proper motion (μ) RA: +46.96[1] mas/yr
Dec.: −62.39[1] mas/yr
Parallax (π)12.39±0.14 mas[1]
Distance263 ± 3 ly
(80.7 ± 0.9 pc)
Absolute magnitude (MV)−0.63[5]
Details
Mass1.92[2] M☉
Radius30±0.04[6] R☉
Luminosity241±7[7] L☉
Surface gravity (log g)1.78±0.04[7] cgs
Temperature4,238±22[7] K
Metallicity −0.06±0.05[7] dex
Rotational velocity (v sin i)4.5[4] km/s
Age2.47[2] Gyr
Other designations
Ukdah, ι Hya, 35 Hydrae, BD−00°2231, FK5 1250, HD 83618, HIP 47431, HR 3845, SAO 137035.[8]
Database references
SIMBADdata

Iota Hydrae (ι Hydrae, abbreviated Iota Hya, ι Hya), formally named Ukdah /ˈʌkdə/,[9] is a star in the constellation of Hydra, about 8° to the north-northwest of Alphard (Alpha Hydrae)[10] and just to the south of the celestial equator.[11] Visible to the naked eye, it is a suspected variable star with an apparent visual magnitude that ranges between 3.87 and 3.91.[3] Based upon an annual parallax shift of 12.39 mas measured during the Hipparcos mission,[1] it is located around 263 light-years distant.

Nomenclature

ι Hydrae (Latinised to Iota Hydrae) is the star's Bayer designation.

This star along with Tau1 Hydrae, Tau2 Hydrae and 33 Hydrae (A Hydrae), were Ptolemy's Καμπή (Kampē); but Kazwini knew them as عقدة ʽuqdah (or ʽuḳdah) "knot".[12] According to a 1971 NASA memorandum,[13] Ukdah was the name of an asterism of four stars: Tau1 Hydrae as Uḳdah I, Tau2 Hydrae as Uḳdah II, 33 Hydrae as Uḳdah III and Iota Hydrae as Uḳdah IV. In 2016, the IAU organized a Working Group on Star Names (WGSN)[14] to catalog and standardize proper names for stars. The WGSN approved the name Ukdah for Iota Hydrae on 1 June 2018 and it is now so included in the List of IAU-approved Star Names.[9]

In Chinese, 星宿 (Xīng Sù), meaning Star or asterism, refers to an asterism consisting of ι Hydrae, Alphard, τ1 Hydrae, τ2 Hydrae, 26 Hydrae, 27 Hydrae, HD 82477 and HD 82428.[15] Consequently, ι Hydrae are known as 星宿四 (Xīng Sù sì, English: the Fourth Star of Star).[16]

Properties

This is an evolved K-type giant star with a stellar classification of K2.5 III.[2] It is a Barium star, which means that, for a giant star, it displays unusually strong absorption lines of singly-ionized barium and strontium.[17] Iota Hydrae has nearly twice the mass of the Sun[2] and has expanded to 30 times the Sun's radius.[6] It is around 2.5 billion years old[2] and is spinning with a leisurely projected rotational velocity of 4.5 km/s.[4] It may be a member of the Wolf 630 moving group of stars that share a common trajectory through space.[18]

References

  1. ^ a b c d e f 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.
  2. ^ a b c d e f g Luck, R. Earle (September 2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal, 150 (3): 23, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, S2CID 118505114, 88.
  3. ^ a b Samus, N. N.; Durlevich, O. V.; et al. (2009), "General Catalogue of Variable Stars", VizieR On-line Data Catalog, 1, Bibcode:2009yCat....102025S.
  4. ^ a b c Massarotti, Alessandro; et al. (January 2008), "Rotational and radial velocities for a sample of 761 HIPPARCOS giants and the role of binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209.
  5. ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  6. ^ a b Baines, Ellyn K.; Armstrong, J. Thomas; Schmitt, Henrique R.; Zavala, R. T.; Benson, James A.; Hutter, Donald J.; Tycner, Christopher; Van Belle, Gerard T. (2018), "Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer", The Astronomical Journal, 155 (1): 30, arXiv:1712.08109, Bibcode:2018AJ....155...30B, doi:10.3847/1538-3881/aa9d8b, S2CID 119427037.
  7. ^ a b c d Soubiran, C.; Creevey, O. L.; Lagarde, N.; Brouillet, N.; Jofré, P.; Casamiquela, L.; Heiter, U.; Aguilera-Gómez, C.; Vitali, S.; Worley, C.; de Brito Silva, D. (February 2024), Gaia FGK benchmark stars: Fundamental Teff and log g of the third version, vol. 682, p. 23, arXiv:2310.11302, Bibcode:2024A&A...682A.145S, doi:10.1051/0004-6361/202347136
  8. ^ "iot Hya". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-01-04.{{cite web}}: CS1 maint: postscript (link)
  9. ^ a b "Naming Stars". IAU.org. Archived from the original on 10 March 2025. Retrieved 18 June 2018.
  10. ^ O'Meara, Steve (2007), Herschel 400 Observing Guide, Cambridge University Press, p. 84, ISBN 978-0521858939.
  11. ^ Moore, Patrick (2013), The Observer's Year: 366 Nights of the Universe, The Patrick Moore Practical Astronomy Series, Springer Science & Business Media, p. 71, ISBN 978-1447136132.
  12. ^ Allen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York, NY: Dover Publications Inc. p. 250. ISBN 0-486-21079-0. Retrieved 2010-12-12. {{cite book}}: ISBN / Date incompatibility (help)
  13. ^ Jack W. Rhoads - Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars, Jet Propulsion Laboratory, California Institute of Technology; November 15, 1971
  14. ^ "IAU Working Group on Star Names (WGSN)". Archived from the original on 10 June 2016. Retrieved 22 May 2016.
  15. ^ (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.
  16. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 29 日 Archived 2011-05-22 at the Wayback Machine
  17. ^ Lu, Phillip K. (June 1991), "Taxonomy of barium stars", Astronomical Journal, 101: 2229–2254, Bibcode:1991AJ....101.2229L, doi:10.1086/115845.
  18. ^ McDonald, A. R. E.; Hearnshaw, J. B. (August 1983), "The Wolf 630 moving group of stars", Monthly Notices of the Royal Astronomical Society, 204 (3): 841–852, Bibcode:1983MNRAS.204..841M, doi:10.1093/mnras/204.3.841.
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