Tau1 Aquarii

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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
Distance320 ± 10 ly
(97 ± 4 pc)
Absolute magnitude (MV)+0.74[6]
Radius2.0[7] R
Luminosity53[6] L
Age100[8] Myr
Other designations
τ1 Aqr, 69 Aquarii, ADS 16268, BD–14 6346, HD 215766, HIP 112542, HR 8673, SAO 165298.[9]
Database references

Tau1 Aquarii, Latinized from 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[8] million years old and has twice the Sun's radius.[7] When examined in the infrared band, it displays an excess emission that is a characteristic of stars with an orbiting debris disk; the model that best fits the data suggests there are two concentric circumstellar disks.[8]


  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 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 Institute Washington D.c. Publication, Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W.
  6. ^ a b 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.
  7. ^ 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.
  8. ^ 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.
  9. ^ "* tau01 Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-07-03.

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