40 Aquarii

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40 Aquarii
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension  22h 13m 26.37997s[1]
Declination −11° 55′ 34.0405″[1]
Apparent magnitude (V) 6.93[2]
Spectral type G5 IV[3]
B−V color index +0.762±0.008[4]
Radial velocity (Rv)−2.9±0.3[5] km/s
Proper motion (μ) RA: +20.95[6] mas/yr
Dec.: −20.05[6] mas/yr
Parallax (π)4.4915 ± 0.0371[1] mas
Distance726 ± 6 ly
(223 ± 2 pc)
Absolute magnitude (MV)−0.47[4]
[1] R
Luminosity154.44[4] L
Surface gravity (log g)2.69[7] cgs
Temperature5,355±80[7] K
Metallicity [Fe/H]−0.13[7] dex
Age100[7] Myr
Other designations
40 Aqr, BD−12° 6209, HD 210845, HIP 109720, SAO 164935[8]
Database references

40 Aquarii is a star in the equatorial constellation of Aquarius. 40 Aquarii is its Flamsteed designation; it was too faint to be included in the Bright Star Catalogue.[9] The brightness of this star is below the normal limit for visibility with the naked eye, having an apparent visual magnitude of 6.93.[2] Based upon parallax measurements, it is located about 726 light-years (223 parsecs) away from the Sun,[1] it is moving closer to the Earth with a heliocentric radial velocity of -3 km/s.[5] 40 Aquarii is positioned near the ecliptic and thus is subject to lunar occultations.[10]

The stellar classification for 40 Aquarii is G5 IV,[3] matching a G-type, yellow-hued subgiant star that has exhausted the supply of hydrogen at its core and has begun to evolve into a giant, it is around 100[7] million years old with 10[1] times the girth of the Sun. The star is radiating 154[4] times the luminosity of the Sun from its photosphere at an effective temperature of 5,355 K.[7]


  1. ^ a b c d e f 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 Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H.
  3. ^ a b Houk, N.; Smith-Moore, M. (1988). "Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. Volume 4, Declinations -26°.0 to -12°.0". Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. 4. Bibcode:1988mcts.book.....H.
  4. ^ a b c d 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.
  5. ^ a b Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065.
  6. ^ a b van Leeuwen, F. (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.
  7. ^ a b c d e f g Holmberg, J.; et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics, 501 (3): 941–947, arXiv:0811.3982, Bibcode:2009A&A...501..941H, doi:10.1051/0004-6361/200811191.
  8. ^ "* 40 Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 7 August 2017.
  9. ^ Bidelman, W. P. (1990). "Flamsteed stars not contained in the Yale "Catalogue of Bright Stars"". Bulletin d'Information du Centre de Donnees Stellaires. 38: 13. Bibcode:1990BICDS..38...13B.
  10. ^ Boehme, D. (1978). "Derivation of Angular Diameters of Stars from Lunar Occultations". Astronomische Nachrichten. 299: 243. Bibcode:1978AN....299..243B. doi:10.1002/asna.19782990505. See p. 256.