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Xi Aquarii

Xi Aquarii is a binary star system in the equatorial constellation of Aquarius. Its name is a Bayer designation that is Latinized from ξ Aquarii, and abbreviated Xi Aqr or ξ Aqr. The system is visible to the naked eye as a point of light with an apparent visual magnitude of 4.7.[4] The two components are designated Xi Aquarii A (also named Bunda[11]) and B. Based upon parallax measurements, this system lies at a distance of approximately 179 light-years (55 parsecs) from the Sun.[1] It is drifting closer with a heliocentric radial velocity of –26 km/s.[5] The position of this system near the ecliptic means it is subject to lunar occultation.[12]

Xi Aquarii is a single-lined spectroscopic binary system, which means that the presence of an unseen orbiting companion can be inferred from Doppler shifts in the spectral absorption lines. The two bodies orbit each other with a period of 8,016 days (22 y) and an eccentricity of 0.54.[7] The primary component, Xi Aquarii A, is an A-type main sequence star with a stellar classification of A7 V.[3] It has about 1.7[2] times the mass of the Sun and is spinning rapidly with a projected rotational velocity of 170 km/s.[8] The star is radiating 36[8] times the luminosity of the Sun from its photosphere at an effective temperature of 8,140 K.[2]

The orbital data is consistent with the secondary component, Xi Aquarii B, being either a red dwarf or a white dwarf star.[6]

Nomenclature

ξ Aquarii (Latinised to Xi Aquarii) is the binary's Bayer designation. The designations of the two components as Xi 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).[13]

Along with Beta Aquarii (Sadalsuud) it constituted the Persian lunar mansion Bunda.[14] In 2016, the IAU organized a Working Group on Star Names (WGSN)[15] to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[16] It approved the name Bunda for the component Xi Aquarii A on 1 June 2018 and it is now so included in the List of IAU-approved Star Names.[11]

In the catalogue of stars in the Calendarium of Al Achsasi al Mouakket, this star was designated Thanih Saad al Saaoud (ثاني سعد السعود – thānī sa‘d al-su‘ūd), which was translated into Latin as Secunda Fortunæ Fortunarum, meaning "the second of luck of lucks".[17] This star, along with Beta Aquarii and 46 Capricorni, were Saʽd al Suʽud (سعد السعود), "the Luck of Lucks".[14][18]

In Chinese, 天壘城 (Tiān Lěi Chéng), meaning Celestial Ramparts, refers to an asterism consisting of Xi Aquarii, 46 Capricorni, 47 Capricorni, Lambda Capricorni, 50 Capricorni, 18 Aquarii, 29 Capricorni, 9 Aquarii, 8 Aquarii, Nu Aquarii, 14 Aquarii, 17 Aquarii and 19 Aquarii.[19] Consequently, the Chinese name for Xi Aquarii itself is 天壘城一 (Tiān Lěi Chéng yī, English: the First Star of Celestial Ramparts).[20]

References

  1. ^ a b c d e 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.
  2. ^ a b c d e f g Gullikson, Kevin; et al. (August 2016), "The Close Companion Mass-ratio Distribution of Intermediate-mass Stars", The Astronomical Journal, 152 (2): 13, arXiv:1604.06456, Bibcode:2016AJ....152...40G, doi:10.3847/0004-6256/152/2/40, S2CID 119179065, 40.
  3. ^ a b Levato, H. (January 1975), "Rotational velocities and spectral types for a sample of binary systems", Astronomy and Astrophysics Supplement Series, 19: 91–99, Bibcode:1975A&AS...19...91L.
  4. ^ a b c Gutierrez-Moreno, Adelina; et al. (1966), "A System of photometric standards", Publ. Dept. Astron. Univ. Chile, 1, Publicaciones Universidad de Chile, Department de Astronomy: 1–17, Bibcode:1966PDAUC...1....1G.
  5. ^ a b Abt, H. A.; Levy, S. G. (March 1974), "Reinvestigation of certain long-period A-type binaries", Astrophysical Journal, 188: 291–294, Bibcode:1974ApJ...188..291A, doi:10.1086/152716.
  6. ^ a b c Goncharov, G. A.; Kiyaeva, O. V. (April 2002), "Astrometric Orbits from a Direct Combination of Ground-Based Catalogs with the Hipparcos Catalog", Astronomy Letters, 28 (4): 261–271, Bibcode:2002AstL...28..261G, doi:10.1134/1.1467262, S2CID 121692881
  7. ^ a b Abt, Helmut A. (August 2005), "Observed Orbital Eccentricities", The Astrophysical Journal, 629 (1): 507–511, Bibcode:2005ApJ...629..507A, doi:10.1086/431207
  8. ^ a b c d Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
  9. ^ Soubiran, C.; Le Campion, J.-F.; Cayrel de Strobel, G.; Caillo, A. (June 2010), "The PASTEL catalogue of stellar parameters", Astronomy and Astrophysics, 515: A111, arXiv:1004.1069, Bibcode:2010A&A...515A.111S, doi:10.1051/0004-6361/201014247, S2CID 118362423.
  10. ^ "ksi Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-07-02.
  11. ^ a b "Naming Stars". International Astronomical Union. Retrieved 18 June 2018.
  12. ^ Herr, Richard B. (April 1969), "Identification List of Spectroscopic and Eclipsing Binaries Subject to Occultations by the Moon", Publications of the Astronomical Society of the Pacific, 81 (479): 105, Bibcode:1969PASP...81..105H, doi:10.1086/128748.
  13. ^ Hessman, F. V.; et al. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 [astro-ph.SR].
  14. ^ a b Allen, R. H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York: Dover Publications Inc, p. 52, ISBN 0-486-21079-0, retrieved 2010-12-12. {{citation}}: ISBN / Date incompatibility (help)
  15. ^ IAU Working Group on Star Names (WGSN), International Astronomical Union, retrieved 2016-05-22.
  16. ^ WG Triennial Report (2015-2018) - Star Name (PDF), International Astronomical Union, p. 5, retrieved 2018-07-14.
  17. ^ Knobel, E. B. (June 1895), "Al Achsasi Al Mouakket, on a catalogue of stars in the Calendarium of Mohammad Al Achsasi Al Mouakket", Monthly Notices of the Royal Astronomical Society, 55 (8): 429, Bibcode:1895MNRAS..55..429K, doi:10.1093/mnras/55.8.429.
  18. ^ β Aqr as Nir Saad al Saaoud or Lucida Fortunæ Fortunarum (the brightest of luck of lucks) and ξ Aqr as Thanih Saad al Saaoud or Secunda Fortunæ Fortunarum (the second of luck of lucks). c Cap should be Thalath Fortunæ Fortunarum or Tertia Fortunæ Fortunarum (the third of luck of lucks) consistently, but Al Achsasi Al Mouakket was not designated the title for this star with uncleared consideration. Possibly according to the differences of opinion with R. H. Allen.
  19. ^ (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.
  20. ^ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived August 11, 2010, at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.