Kappa Aquarii
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| 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 mas/yr[2] Dec.: −119.631 mas/yr[2] |
| Parallax (π) | 14.7149±0.0995 mas[2] |
| Distance | 222 ± 1 ly (68.0 ± 0.5 pc) |
| Absolute magnitude (MV) | +0.96[1] |
| Details | |
| Mass | 2.554±0.128[7] M☉ |
| Radius | 13[6] R☉ |
| Luminosity | 60[6] L☉ |
| Surface gravity (log g) | 2.63±0.08[3] cgs |
| Temperature | 4,581±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 | |
| SIMBAD | data |
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
[edit]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
[edit]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
[edit]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
[edit]- ^ a b 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.
- ^ a b c d Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c d Soubiran, C.; et al. (July 1, 2022), "Assessment of [Fe/H] determinations for FGK stars in spectroscopic surveys", Astronomy and Astrophysics, 663: A4, arXiv:2112.07545, Bibcode:2022A&A...663A...4S, doi:10.1051/0004-6361/202142409, ISSN 0004-6361.
- ^ a b 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, Bibcode:1989ApJS...71..245K, doi:10.1086/191373, ISSN 0067-0049.
- ^ a b 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.
- ^ a b c d e f g h i j 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, S2CID 121883397.
- ^ Kervella, Pierre; et al. (2019), "Stellar and substellar companions of nearby stars from Gaia DR2: Binarity from proper motion anomaly", Astronomy & Astrophysics, 623: A72, arXiv:1811.08902, Bibcode:2019A&A...623A..72K, doi:10.1051/0004-6361/201834371, ISSN 0004-6361.
- ^ "kap Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-07-01.
- ^ a b Naming Stars, IAU.org, retrieved 16 December 2017.
- ^ Hessman, F. V.; et al. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 [astro-ph.SR].
- ^ a b Allen, Richard Hinckley, Star Names — Their Lore and Meaning: Aquarius (Dover ed.), retrieved 2012-07-01.
- ^ IAU Working Group on Star Names (WGSN), International Astronomical Union, retrieved 22 May 2016.
- ^ WG Triennial Report (2015-2018) - Star Names (PDF), p. 5, retrieved 2018-07-14.
- ^ (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.
- ^ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived 2010-08-18 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
- ^ 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. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
- ^ a b "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on February 22, 2012, retrieved 2012-01-16.
- ^ LacusCurtius • Allen's Star Names — Aquarius
