77 Aquarii

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77 Aquarii
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension 22h 54m 45.47121s[1]
Declination –16° 16′ 19.0392″[1]
Apparent magnitude (V) 5.55[2]
Spectral type K1 III[3]
U−B color index +1.089[2]
B−V color index +1.104[2]
Radial velocity (Rv) –36.3[4] km/s
Proper motion (μ) RA: –219.73[1] mas/yr
Dec.: –87.78[1] mas/yr
Parallax (π) 24.28 ± 0.56[1] mas
Distance 134 ± 3 ly
(41.2 ± 0.9 pc)
Radius 6[5] R
Luminosity 13.5[5] L
Surface gravity (log g) 2.8[5] cgs
Temperature 4,581[5] K
Metallicity [Fe/H] +0.03[5] dex
Rotational velocity (v sin i) 3.9[5] km/s
Other designations
BD–17 6619, HD 216640, HIP 113148, HR 8711, SAO 165376.[6]

77 Aquarii (abbreviated 77 Aqr) is a star in the equatorial constellation of Aquarius. 77 Aquarii is its Flamsteed designation. It has an apparent visual magnitude of 5.55[2] and is around 134 light-years (41 parsecs) from Earth. This is a giant star with a stellar classification of K1 III.[3] It has six times the radius of the Sun and shines with 13.5 times the Sun's luminosity. The outer atmosphere has an effective temperature of 4,581 K,[5] giving it the orange-hued glow of a K-type star.[7]


  1. ^ a b c d e van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752free to read, 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; Smith-Moore, M. (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. ^ 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 g Massarotti, Alessandro; et al. (January 2008), "Rotational and radial velocities for a sample of 761 HIPPARCOS giants and the role of binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209. 
  6. ^ "77 Aqr -- Variable Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-07-15. 
  7. ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, retrieved 2012-01-16 

External links[edit]