108 Aquarii

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108 Aquarii
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension 23h 51m 21.33832s[1]
Declination –18° 54′ 32.9937″[1]
Apparent magnitude (V) 5.194[2]
Characteristics
Spectral type Ap[3]
U−B color index –0.396[2]
B−V color index –0.135[2]
Variable type α² CVn[4]
Astrometry
Radial velocity (Rv) +12.7[5] km/s
Proper motion (μ) RA: +26.82[1] mas/yr
Dec.: –4.27[1] mas/yr
Parallax (π) 10.23 ± 0.31[1] mas
Distance 319 ± 10 ly
(98 ± 3 pc)
Absolute magnitude (MV) +0.08[6]
Details
Mass 3.21 ± 0.15[6] M
Radius 2.5 ± 0.3[6] R
Luminosity 132[6] L
Surface gravity (log g) 4.27 ± 0.10[6] cgs
Temperature 12,274[6] K
Metallicity [Fe/H] +0.90[7] dex
Rotation 3.74 days[6]
Rotational velocity (v sin i) 30[8] km/s
Other designations
BD–19 6522, HD 223640, HIP 117629, HR 9031, SAO 165918.[4]
Data sources:
Hipparcos Catalogue,
CCDM (2002),
Bright Star Catalogue (5th rev. ed.)

108 Aquarii (abbreviated 108 Aqr) is a star in the equatorial constellation of Aquarius. 108 Aquarii is the Flamsteed designation although it also bears the Bayer designation i3 Aquarii and the variable star designation ET Aquarii. It has an apparent visual magnitude of 5.194[2] and can be seen with the naked eye under suitably dark skies. Based upon an annual parallax shift of 10.23[1] (with a 3% margin of error), the distance to this star is 319 light-years (98 parsecs).

This is an Ap star; meaning it has a peculiar spectrum that shows an overabundance of certain elements. It has more than three times the mass of the Sun and is 2.5 times the Sun's radius.[6] 108 Aquarii is radiating 132[6] times the luminosity of the Sun from its outer atmosphere at an effective temperature of 12,274 K.[6] At this heat, the star has the white hue of an A-type star.[9]

References[edit]

  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 c d 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. ^ 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 "ET Aqr -- Variable Star of alpha2 CVn type", SIMBAD Astronomical Object Database (Centre de Données astronomiques de Strasbourg), retrieved 2012-07-15. 
  5. ^ Wilson, R. E. (1953), General Catalogue of Stellar Radial Velocities, Carnegie Institute of Washington, D.C., Bibcode:1953GCRV..C......0W. 
  6. ^ a b c d e f g h i j North, P. (June 1998), "Do SI stars undergo any rotational braking?", Astronomy and Astrophysics 334: 181–187, arXiv:astro-ph/9802286, Bibcode:1998A&A...334..181N. 
  7. ^ Vilhu, O.; Tuominen, I. V.; Boyarchuk, A. A. (1976), "Abundance Studies of Peculiar B Stars", in Weiss, W. W.; Jenkner, H.; Wood, H. J., Physics of Ap Stars, Proceedings of IAU Colloq. 32, held in Vienna, Austria, 8-11 September, 1976, Universitatssternwarte Wien, p. 563, Bibcode:1976paps.coll..563V. 
  8. ^ Abt, Helmut A.; Levato, Hugo; Grosso, Monica (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi:10.1086/340590. 
  9. ^ Przybylski, A.; Kennedy, P. M. (1965), "Radial velocities and three-colour photometry of 166 southern stars", Monthly Notices of the Royal Astronomical Society 131: 95–104, Bibcode:1965MNRAS.131...95P, doi:10.1093/mnras/131.1.95. 

External links[edit]