24 Aquarii

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24 Aquarii
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension  21h 39m 31.53468s[1]
Declination −00° 03′ 04.1095″[1]
Apparent magnitude (V) 6.66[2]
Spectral type F7 III[3] OR F7V + ? + F9V[4]
B−V color index +0.52[5]
Radial velocity (Rv)−15.86±0.06[2] km/s
Proper motion (μ) RA: +215.367[1] mas/yr
Dec.: +17.077[1] mas/yr
Parallax (π)25.0839 ± 0.6277[1] mas
Distance130 ± 3 ly
(39.9 ± 1.0 pc)
Absolute magnitude (MV)3.45[2]
Period (P)48.65 yr
Semi-major axis (a)0.448″
Eccentricity (e)0.868
Inclination (i)58.0°
Longitude of the node (Ω)139.3°
Periastron epoch (T)1971.55
Argument of periastron (ω)
24 Aqr Aa
Mass1.25 M
[1] R
Luminosity2.864±0.080[1] L
Temperature6,231 K
Metallicity [Fe/H]–0.09 dex
Age3.5 Gyr
Other designations
24 Aqr, BD−00°4245, HD 206058, HIP 106942, SAO 145566, WDS J21395-0003, LTT 8626
Database references

24 Aquarii is a triple star[6] system in the equatorial constellation of Aquarius. 24 Aquarii is the Flamsteed designation. The apparent magnitude of this system is 6.66,[2] which, according to the Bortle Dark-Sky Scale, means it is a faint star that is just visible to the naked eye from dark, rural skies. It has an annual parallax shift of 25.08 mas,[1] which is equivalent to a distance of 130 light-years (40 parsecs) from Earth. The system is moving closer to the Earth with a heliocentric radial velocity of −16 km/s.[2]

The calculated orbit of the visual binary has a period of 48.65 years and a large eccentricity of 0.868.[6] The primary, component A, is itself a single-lined spectroscopic binary with a period of 5.8839 days and an eccentricity of 0.071±0.006.[4] One study gives the system a stellar classification of F7 III,[3] suggesting it contains an evolved giant star. Other classifications give classes matching F-type main-sequence stars for components Aa and B.[4]


  1. ^ a b c d e f g h Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. ^ a b c d e 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.
  3. ^ a b Fehrenbach, C. (1966), "La mesure des vitesses radiales au prisme objectif XIX. Liste de 893 vitesses radiales determinees au prisme objectif a vision directe", Publications de l'Observatoire de Haute-Provence, 8: 25, Bibcode:1966POHP....8...25F.
  4. ^ a b c Griffin, R. F.; et al. (June 1996), "Spectroscopic binary orbits from photoelectric radial velocities. Paper 128: 24 Aquarii", The Observatory, 116: 162–175, Bibcode:1996Obs...116..162G.
  5. ^ Cousins, A. W. J.; Stoy, R. H. (1962), "Photoelectric magnitudes and colours of Southern stars", Royal Observatory Bulletin, 64, Bibcode:1962RGOB...64..103C.
  6. ^ a b c Branham, Richard L., Jr. (March 2005), "Calculating the Apparent Orbit of a Double Star", The Astrophysical Journal, 622 (1): 613–61, Bibcode:2005ApJ...622..613B, doi:10.1086/427870.
  7. ^ Casagrande, L.; et al. (June 2011), "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey", Astronomy and Astrophysics, 530: A138, arXiv:1103.4651, Bibcode:2011A&A...530A.138C, doi:10.1051/0004-6361/201016276.

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