89 Aquarii

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89 Aquarii
Diagram showing star positions and boundaries of the Aquarius constellation and its surroundings
Cercle rouge 100%.svg
Location of 89 Aquarii (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension  23h 09m 54.89736s[1]
Declination –22° 27′ 27.4192″[1]
Apparent magnitude (V) +4.69[2]
Spectral type G3 II + A2 V[3]
U−B color index +0.39[2]
B−V color index +0.65[2]
Radial velocity (Rv)-4.8[4] km/s
Proper motion (μ) RA: +32.61[1] mas/yr
Dec.: –9.76[1] mas/yr
Parallax (π)6.47 ± 0.68[1] mas
Distanceapprox. 500 ly
(approx. 150 pc)
Absolute magnitude (MV)0.1/1.5[5]
89 Aqr A
Mass2.9[5] M
Surface gravity (log g)3.62[6] cgs
Temperature5,640[6] K
Metallicity [Fe/H]+0.27[6] dex
Age320[5] Myr
89 Aqr B
Mass2.0[5] M
Temperature8,912[5] K
Other designations
CD–23 17771, HIP 114375, HR 8817, SAO 191687.[7]
89 Aqr A: HD 218640.
89 Aqr B: HD 218641.
Database references

89 Aquarii (abbreviated 89 Aqr) is a binary star[3] system in the equatorial constellation of Aquarius. 89 Aquarii is the Flamsteed designation, though it also bears the Bayer designation c3 Aquarii.[8] The apparent visual magnitude of +4.69[2] is bright enough to be seen with the naked eye. Its distance from Earth is roughly 500 light-years (150 pc), based upon parallax measurements with an 11% margin of error.[1]

The primary component of this system has a magnitude of 5.27 and a stellar classification of G3 II, which suggests this is an evolved star in the bright giant stage. The companion is an A-type main sequence star with a stellar classification of A2 V;[3] as of 2010, it is located at an angular separation of 0.1843 arcseconds along a position angle of 135.1°.[9] They orbit each other with an estimated period of 201 years and a semimajor axis of 0.45 arcseconds.[5]


  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 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.
  3. ^ a b c 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.
  4. ^ Wilson, R. E. (1953), General Catalogue of Stellar Radial Velocities, Carnegie Institute of Washington, D.C., Bibcode:1953GCRV..C......0W.
  5. ^ a b c d e f Parsons, Sidney B. (May 2004), "New and Confirmed Triple Systems with Luminous Cool Primaries and Hot Companions", The Astronomical Journal, 127 (5): 2915–2930, Bibcode:2004AJ....127.2915P, doi:10.1086/383546.
  6. ^ a b c McWilliam, Andrew (December 1990), "High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances", Astrophysical Journal Supplement Series, 74: 1075–1128, Bibcode:1990ApJS...74.1075M, doi:10.1086/191527.
  7. ^ "* 89 Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-07-13.
  8. ^ [1] database record, HD-DM-GC-HR-HIP-Bayer-Flamsteed Cross Index, N. D. Kostjuk, Institute of Astronomy of Russian Academy of Sciences, 2002; CDS ID IV/27A.
  9. ^ Tokovinin, A.; et al. (December 2010), "High-Resolution Imaging at the SOAR Telescope", Publications of the Astronomical Society of the Pacific, 122 (898): 1483–1494, arXiv:1010.4176, Bibcode:2010PASP..122.1483T, doi:10.1086/657903.

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