66 Aquarii

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66 Aquarii
Diagram showing star positions and boundaries of the Aquarius constellation and its surroundings
Cercle rouge 100%.svg
Location of 66 Aquarii (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension 22h 43m 35.23307s[1]
Declination –18° 49′ 49.3557″[1]
Apparent magnitude (V) 4.673[2]
Spectral type K3 III[3]
U−B color index +1.549[2]
B−V color index +1.376[2]
Variable type suspected[4]
Radial velocity (Rv)+21.6[5] km/s
Proper motion (μ) RA: –31.73[1] mas/yr
Dec.: –28.54[1] mas/yr
Parallax (π)7.53 ± 0.26[1] mas
Distance430 ± 10 ly
(133 ± 5 pc)
Radius37[6] R
Surface gravity (log g)2.06[7] cgs
Temperature4,170[7] K
Metallicity [Fe/H]–0.23[7] dex
Rotational velocity (v sin i)10[8] km/s
Other designations
BD−19° 6324, HD 215167, HIP 112211, HR 8649, SAO 165252[9]
Database references

66 Aquarii (abbreviated 66 Aqr) is a star in the equatorial constellation of Aquarius. 66 Aquarii is the Flamsteed designation though the star also bears the Bayer designation of g1 Aquarii.[10] It is visible to the naked eye with an apparent visual magnitude of 4.673.[2] Based upon an annual parallax shift of 7.53 milliarcseconds,[1] the distance to this star is about 430 light-years (130 parsecs).

This is an evolved giant star with a stellar classification of K3 III.[3] It has expanded to 37 times the radius of the Sun[6] and is radiating energy from its outer envelope at an effective temperature of 4,170 K.[7] This gives it the orange-hued glow of a K-type star.[11] It is a suspected variable star that ranges in magnitude between 4.66 and 4.71.[4]


  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 Jennens, P. A.; Helfer, H. L. (September 1975), "A new photometric metal abundance and luminosity calibration for field G and K giants.", Monthly Notices of the Royal Astronomical Society, 172: 667–679, Bibcode:1975MNRAS.172..667J, doi:10.1093/mnras/172.3.667.
  3. ^ a b Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1988mcts.book.....H.
  4. ^ a b Kazarovets, E. V.; Samus, N. N.; Durlevich, O. V. (December 1998), New Catalogue of Suspected Variable Stars. Supplement, 1.0, 4655, Information Bulletin on Variable Stars, p. 1, Bibcode:1998IBVS.4655....1K
  5. ^ Wilson, Ralph Elmer (1953), General catalogue of stellar radial velocities, Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W.
  6. ^ a b Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics", Astronomy and Astrophysics, 367 (2): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451.
  7. ^ a b c d 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.
  8. ^ Bernacca, P. L.; Perinotto, M. (1970), "A catalogue of stellar rotational velocities", Contributi Osservatorio Astronomico di Padova in Asiago, 239 (1), Bibcode:1970CoAsi.239....1B.
  9. ^ "* g Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-07-14.
  10. ^ HD 215167, 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.
  11. ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on March 10, 2012, retrieved 2012-01-16

External links[edit]