Tau2 Aquarii

For other star systems with this Bayer designation, see Tau Aquarii.
τ2 Aquarii
Diagram showing star positions and boundaries of the Aquarius constellation and its surroundings


Location of τ1 Aquarii (circled)

Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension 22h 49m 35.50157s[1]
Declination –13° 35′ 33.4767″[1]
Apparent magnitude (V) +4.042[2]
Characteristics
Spectral type K5 III[3]
U−B color index +1.948[2]
B−V color index +1.566[2]
Astrometry
Radial velocity (Rv)+1.0[4] km/s
Proper motion (μ) RA: –13.71[1] mas/yr
Dec.: –39.03[1] mas/yr
Parallax (π)10.27 ± 0.29[1] mas
Distance318 ± 9 ly
(97 ± 3 pc)
Details
Radius53[5] R☉
Other designations
Tau Aquarii, 71 Aquarii, BD–14 6354, FK5 861, HD 216032, HIP 112716, HR 8679, NSV 14329, SAO 165321.[6]

Tau2 Aquarii (τ2 Aqr, τ2 Aquarii) is the Bayer designation for a star in the equatorial constellation of Aquarius. It is visible to the naked eye with an apparent visual magnitude of +4.0.[2] This is an orange-hued[7] giant star with a stellar classification of K5 III.[3] The measured angular diameter, after correction for limb darkening, is 5.12 ± 0.05 mas.[8] At an estimated distance of 318 light-years (97 parsecs) based on parallax measurements,[1] this yields a physical size of about 53 times the radius of the Sun.[5]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 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. ↑ 2.0 2.1 2.2 2.3 Gutierrez-Moreno, Adelina et al. (1966), A System of photometric standards 1, Publicaciones Universidad de Chile, Department de Astronomy, pp. 1–17, Bibcode:1966PDAUC...1....1G.
  3. ↑ 3.0 3.1 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. ↑ Wielen, R. et al. (1999), Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions (35), Astronomisches Rechen-Institut Heidelberg, Bibcode:1999VeARI..35....1W.
  5. ↑ 5.0 5.1 Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. The radius (R*) is given by:
    \begin{align} 2\cdot R_* & = \frac{(97\cdot 5.12\cdot 10^{-3})\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \\ & \approx 107\cdot R_{\bigodot} \end{align}
  6. ↑ "tau Aqr -- Star in double system", SIMBAD (Centre de Données astronomiques de Strasbourg), retrieved 2012-02-08
  7. ↑ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, retrieved 2012-01-16
  8. ↑ Richichi, A.; Percheron, I.; Khristoforova, M. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics 431: 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039

External links