Astronomy:Kappa Aquarii

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Short description: Star in the constellation Aquarius
κ Aquarii
Location of κ Aquarii (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Aquarius[1]
Right ascension  22h 37m 45.381s[2]
Declination −04° 13′ 41.00″[2]
Apparent magnitude (V) 5.030±0.009[3]
Characteristics
Spectral type K1.5 IIIb CN0.5[4]
U−B color index +1.16[5]
B−V color index +1.142[6]
Astrometry
Radial velocity (Rv)+7.31±0.16[6] km/s
Proper motion (μ) RA: −69.411[2] mas/yr
Dec.: −119.631[2] mas/yr
Parallax (π)14.7149 ± 0.0995[2] mas
Distance222 ± 1 ly
(68.0 ± 0.5 pc)
Absolute magnitude (MV)+0.96[1]
Details
Mass2.554±0.128[7] M☉
Radius13[6] R☉
Luminosity60[6] L☉
Surface gravity (log g)2.63±0.08[3] cgs
Temperature4,581±5[6] K
Metallicity [Fe/H]+0.14±0.04[3] dex
Rotational velocity (v sin i)3.8[6] km/s
Other designations
Situla, 63 Aquarii, BD−04 5716, FK5 1595, GC 31581, HD 214376, HIP 111710, HR 8610, SAO 146210, PPM 206585, WDS J22378-0414A[8]
Database references
SIMBADdata

Kappa Aquarii is a candidate binary star in the equatorial constellation of Aquarius. Its identifier is a Bayer designation that is Latinized from κ Aquarii, and abbreviated Kappa Aqr or κ Aqr, respectively. This system is visible to the naked eye, but it is faint at an apparent visual magnitude of 5.03.[3] Based upon parallax measurements, it is around 214 light-years (66 parsecs) from the Sun.[5] The system is drifting further away from the Sun with a radial velocity of +7.3 km/s.[6]

The two components are designated Kappa Aquarii A and B. The former is named Situla, pronouced /ˈsɪtjuːlə/, the traditional name for the system.[9]

Nomenclature

κ Aquarii (Latinised to Kappa Aquarii) is the system's Bayer designation. The designations of the two components as Kappa Aquarii A and B derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).[10]

It bore the traditional name Situla, a Latin word meaning "bucket" or "water jar".[11] In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[12] to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[13] It approved the name Situla for the component Kappa Aquarii A on 12 September 2016 and it is now so included in the List of IAU-approved Star Names.[9]

In Chinese, 虛梁 (Xū Liáng), meaning Temple, refers to an asterism consisting of Kappa Aquarii, 44 Aquarii, 51 Aquarii and HD 216718.[14] Consequently, the Chinese name for Kappa Aquarii itself is 虛梁三 (Xū Liáng sān, English: the Third Star of Temple).[15] From this Chinese name, the name Heu Leang has appeared, meaning "the empty bridge".[11]

Properties

Kappa Aquarii is most probably a wide binary star system.[16] The brighter component is a giant star with a stellar classification of K1.5 IIIb CN0.5.[4] It has exhausted the supply of hydrogen at its core and has expanded to 13[6] times the radius of the Sun. It is radiating 60[6] times the Sun's luminosity from its photosphere at an effective temperature of 4,581 K,[6] giving it the orange-hued glow of a K-type star.[17]

The fainter companion star is located at an angular separation of 98.3 arcseconds and has an apparent magnitude of 8.8.[17]

In culture

Endymion, an 1818 poem by John Keats, describes the star in its form as a water urn thus:

Crystalline brother of the belt of heaven,
Aquarius! to whom King Jove has given
Two liquid pulse streams 'stead of feather'd wings,
Two fan-like fountains, — thine illuminings.[18]

USS Situla (AK-140) was a United States Navy Crater-class cargo ship named after the star.

References

  1. ↑ 1.0 1.1 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A. 
  2. ↑ 2.0 2.1 2.2 2.3 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  3. ↑ 3.0 3.1 3.2 3.3 Soubiran, C. et al. (July 1, 2022), "Assessment of [Fe/H] determinations for FGK stars in spectroscopic surveys", Astronomy and Astrophysics 663: A4, doi:10.1051/0004-6361/202142409, ISSN 0004-6361, Bibcode: 2022A&A...663A...4S. 
  4. ↑ 4.0 4.1 Keenan, Philip C.; McNeil, Raymond C. (October 1, 1989), "The Perkins Catalog of Revised MK Types for the Cooler Stars", The Astrophysical Journal Supplement Series 71: 245, doi:10.1086/191373, ISSN 0067-0049, Bibcode: 1989ApJS...71..245K. 
  5. ↑ 5.0 5.1 Nicolet, B. (1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", Astronomy and Astrophysics Supplement Series 34: 1–49, Bibcode: 1978A&AS...34....1N. 
  6. ↑ 6.00 6.01 6.02 6.03 6.04 6.05 6.06 6.07 6.08 6.09 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, doi:10.1088/0004-6256/135/1/209, Bibcode: 2008AJ....135..209M. 
  7. ↑ Kervella, Pierre et al. (2019), "Stellar and substellar companions of nearby stars from Gaia DR2: Binarity from proper motion anomaly", Astronomy & Astrophysics 623: A72, doi:10.1051/0004-6361/201834371, ISSN 0004-6361, Bibcode: 2019A&A...623A..72K. 
  8. ↑ "kap Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=kap+Aqr. 
  9. ↑ 9.0 9.1 Naming Stars, IAU.org, https://www.iau.org/public/themes/naming_stars/, retrieved 16 December 2017. 
  10. ↑ Hessman, F. V.; et al. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 [astro-ph.SR].
  11. ↑ 11.0 11.1 Allen, Richard Hinckley, Star Names — Their Lore and Meaning: Aquarius (Dover ed.), https://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Aquarius*.html, retrieved 2012-07-01. 
  12. ↑ IAU Working Group on Star Names (WGSN), International Astronomical Union, https://www.iau.org/science/scientific_bodies/working_groups/280/, retrieved 22 May 2016. 
  13. ↑ WG Triennial Report (2015-2018) - Star Names, p. 5, https://www.iau.org/static/science/scientific_bodies/working_groups/280/wg-starnames-triennial-report-2015-2018.pdf, retrieved 2018-07-14. 
  14. ↑ Script error: The function "in_lang" does not exist. 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.
  15. ↑ Script error: The function "in_lang" does not exist. 香港太空館 - 研究資源 - 亮星中英對照表 , Hong Kong Space Museum. Accessed on line November 23, 2010.
  16. ↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society 389 (2): 869–879. doi:10.1111/j.1365-2966.2008.13596.x. Bibcode: 2008MNRAS.389..869E. 
  17. ↑ 17.0 17.1 "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html, retrieved 2012-01-16. 
  18. ↑ LacusCurtius • Allen's Star Names — Aquarius



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