Tau2 Aquarii

For other star systems with this Bayer designation, see Tau Aquarii.
τ2 Aquarii


Location of τ2 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)
Absolute magnitude (MV)−1.28[5]
Details
Radius53[6] R☉
Other designations
Tau Aquarii, 71 Aquarii, BD–14 6354, FK5 861, HD 216032, HIP 112716, HR 8679, NSV 14329, SAO 165321.[7]

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[8] 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.[9] 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.[6]

References

  1. 1 2 3 4 5 6 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
  2. 1 2 3 4 Gutierrez-Moreno, Adelina; et al. (1966), "A System of photometric standards", Publ. Dept. Astron. Univ. Chile, Publicaciones Universidad de Chile, Department de Astronomy, 1: 1–17, Bibcode:1966PDAUC...1....1G.
  3. 1 2 Houk, Nancy (1978), "Michigan catalogue of two-dimensional spectral types for the HD stars", Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. Volume 4, Ann Arbor: Dept. of Astronomy, University of Michigan, 4, Bibcode:1988mcts.book.....H.
  4. ↑ Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veröff. Astron. Rechen-Inst. Heidelb, Astronomisches Rechen-Institut Heidelberg, 35 (35), Bibcode:1999VeARI..35....1W.
  5. ↑ Pace, G.; Pasquini, L.; Ortolani, S. (2003). "The Wilson-Bappu effect: A tool to determine stellar distances". Astronomy and Astrophysics. 401 (3): 997. arXiv:astro-ph/0301637Freely accessible. Bibcode:2003A&A...401..997P. doi:10.1051/0004-6361:20030163.
  6. 1 2 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:
  7. ↑ "tau Aqr -- Star in double system", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2012-02-08
  8. ↑ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, retrieved 2012-01-16
  9. ↑ Richichi, A.; Percheron, I.; Khristoforova, M. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 431 (2): 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039
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