Mu Aquarii

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μ Aquarii
Aquarius constellation map.svg
Red circle.svg
Location of μ Aquarii (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension  20h 52m 39.23277s[1]
Declination −08° 58′ 59.9499″[1]
Apparent magnitude (V) 4.731[2]
Spectral type A3m[3]
U−B color index +0.149[2]
B−V color index +0.322[2]
Radial velocity (Rv)−9.1[4] km/s
Proper motion (μ) RA: +45.75[1] mas/yr
Dec.: -33.59[1] mas/yr
Parallax (π)20.74 ± 0.29[1] mas
Distance157 ± 2 ly
(48.2 ± 0.7 pc)
Absolute magnitude (MV)+1.31[5]
Luminosity24.6[6] L
Surface gravity (log g)3.99[6] cgs
Temperature7,181[6] K
Rotational velocity (v sin i)53.7[6] km/s
Other designations
μ Aqr, 6 Aquarii, BD−09 5598, FK5 1547, HD 198743, HIP 103045, HR 7990, SAO 144895.[7]
Database references

Mu Aquarii, Latinized from μ Aquarii, is the Bayer designation for a binary star[8] system in the equatorial constellation of Aquarius. It is visible to the naked eye with a combined apparent visual magnitude of 4.7.[2] Based upon parallax measurements, the distance to this system is about 157 light-years (48 parsecs).[1] Mu Aquarii is a spectroscopic binary with an orbital period of 1,566 days and an eccentricity of 0.23.[9] The combined spectrum matches a stellar classification of A3m, with the 'm' suffix indicating that this is an Am, or chemically peculiar star.[3]

This star together with ν Aquarii is Albulaan /ˌælbjəˈlɑːn/, derived from an Arabic term al-bulaʽān (ألبولعان) meaning "the two swallowers". This star, along with ε Aqr (Albali) and ν Aqr (Albulaan), were al Bulaʽ (البلع), the Swallower.[10][11] In Chinese, 女宿 (Nǚ Xiù), meaning Girl (asterism) (or Woman), refers to an asterism consisting of μ Aquarii, ε Aquarii, 4 Aquarii, 5 Aquarii and 3 Aquarii.[12] Consequently, the Chinese name for μ Aquarii itself is 女宿二 (Nǚ Xiù èr, English: the Second Star of Girl / Woman.)[13]


  1. ^ a b c d e f van Leeuwen, F. (November 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.
  2. ^ a b c d Gutierrez-Moreno, Adelina; et al. (1966), A System of photometric standards, 1, Publicaciones Universidad de Chile, Department de Astronomy, pp. 1–17, Bibcode:1966PDAUC...1....1G.
  3. ^ a b Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819.
  4. ^ Wilson, Ralph Elmer (1953). General Catalogue of Stellar Radial Velocities. Washington: Carnegie Institution of Washington. Bibcode:1953GCRV..C......0W.
  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.
  6. ^ a b c d Schröder, C.; Reiners, A.; Schmitt, J. H. M. M. (January 2009). "Ca II HK emission in rapidly rotating stars. Evidence for an onset of the solar-type dynamo" (PDF). Astronomy and Astrophysics. 493 (3): 1099–1107. Bibcode:2009A&A...493.1099S. doi:10.1051/0004-6361:200810377.
  7. ^ "* 6 Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-07-01.
  8. ^ 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.
  9. ^ Abt, Helmut A. (August 2005), "Observed Orbital Eccentricities", The Astrophysical Journal, 629 (1): 507–511, Bibcode:2005ApJ...629..507A, doi:10.1086/431207.
  10. ^ Davis Jr., G. A. (October 1944), "The Pronunciations, Derivations, and Meanings of a Selected List of Star Names", Popular Astronomy, 52 (3): 12, Bibcode:1944PA.....52....8D.
  11. ^ Allen, R. H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York: Dover Publications Inc, p. 53, ISBN 0-486-21079-0, retrieved 2010-12-12.
  12. ^ (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.
  13. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 14 日

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