Tau1 Aquarii

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For other star systems with this Bayer designation, see Tau Aquarii.
τ1 Aquarii
Diagram showing star positions and boundaries of the Aquarius constellation and its surroundings
Cercle rouge 100%.svg

Location of τ1 Aquarii (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension 22h 47m 42.76932s[1]
Declination –14° 03′ 23.1409″[1]
Apparent magnitude (V) +5.66[2]
Spectral type B9 V[3]
U−B color index –0.25[4]
B−V color index –0.05[4]
Radial velocity (Rv) +15[5] km/s
Proper motion (μ) RA: +30.61[1] mas/yr
Dec.: –9.23[1] mas/yr
Parallax (π) 10.27 ± 0.46[1] mas
Distance 320 ± 10 ly
(97 ± 4 pc)
Radius 2.0[6] R
Age 100[7] Myr
Other designations
69 Aquarii, ADS 16268, BD–14 6346, HD 215766, HIP 112542, HR 8673, SAO 165298.[8]
Data sources:
Hipparcos Catalogue,
CCDM (2002),
Bright Star Catalogue (5th rev. ed.)

Tau1 Aquarii1 Aqr, τ1 Aquarii) is the Bayer designation for a star in the equatorial constellation of Aquarius. With an apparent visual magnitude of 5.66,[2] it is a faint naked eye that requires dark suburban skies for viewing. Parallax measurements made during the Hipparcos mission yield a distance estimate of roughly 320 light-years (98 parsecs) from Earth.[1]

τ1 Aquarii has a stellar classification of B9 V;[3] right along the borderline between a B- and A-type main sequence star. It is around 100[7] million years old and has twice the Sun's radius.[6] When examined in the infrared band, it displays an excess emission that is a characteristic of stars with an orbiting debris disk. Indeed, the model that best fits the data suggests there are two concentric circumstellar disks.[7]


  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:0708.1752free to read, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357. 
  2. ^ a b Corben, P. M.; Stoy, R. H. (1968), "Photoelectric Magnitudes and Colours for Bright Southern Stars", Monthly Notes of the Astronomical Society of Southern Africa, 27: 11, Bibcode:1968MNSSA..27...11C. 
  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 Nicolet, B. (1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", Astronomy and Astrophysics Supplement Series, 34: 1–49, Bibcode:1978A&AS...34....1N. 
  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: 521–524, arXiv:astro-ph/0012289free to read, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451. 
  7. ^ a b c Morales, Farisa Y.; et al. (April 2011), "Common Warm Dust Temperatures Around Main-sequence Stars", The Astrophysical Journal Letters, 730 (2): L29, Bibcode:2011ApJ...730L..29M, doi:10.1088/2041-8205/730/2/L29. 
  8. ^ "69 Aqr -- Star in double system", SIMBAD Astronomical Object Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-07-03. 

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