4 Aquarii

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4 Aquarii
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension 20h 51m 25.74827s[1]
Declination −05° 37′ 35.8719″[1]
Apparent magnitude (V) 5.99[2]
Spectral type F5IV-V[2]
B−V color index 0.46[2]
Radial velocity (Rv) -21.50[3] km/s
Proper motion (μ) RA: 95.47[1] mas/yr
Dec.: 1.78[1] mas/yr
Parallax (π) 16.47 ± 0.59[1] mas
Distance 198 ± 7 ly
(61 ± 2 pc)
Absolute magnitude (MV) 2.07
Rotation 213.39 km/s[2]
Other designations
BD-06° 5604, HD 198571, SAO 144877, WDS J2051.4-0538, HIP 102945, HR 7982.
Database references
Database references
Data sources:
Hipparcos Catalogue,
CCDM (2002),
Bright Star Catalogue (5th rev. ed.)

4 Aquarii (abbreviated 4 Aqr) is a binary star in the constellation Aquarius. 4 Aquarii is the Flamsteed designation. Located approximately 60.72 parsecs (198.0 ly) distant, the combined apparent magnitude of the system is 5.99[2] The spectral type of the primary star is F5IV-V, meaning that it is either a subgiant or a main-sequence star of spectral type F.


  1. ^ a b c d e van Leeuwen, F. (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 e "4 Aquarii". SIMBAD Astronomical Database. Centre de Données astronomiques de Strasbourg. Retrieved 23 October 2014. 
  3. ^ Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. 

Bartkevičius, A.; Gudas, A. (2002). "Kinematics of Hipparcos Visual Binaries. II. Stars with Ground-Based Orbital Solutions". Baltic Astronomy. 11: 153–203. Bibcode:2002BaltA..11..153B.