Iota Aquarii

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Iota Aquarii
Diagram showing star positions and boundaries of the Aquarius constellation and its surroundings
Cercle rouge 100%.svg
Location of ι Aquarii (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension  22h 06m 26.22742s[1]
Declination –13° 52′ 10.8615″[1]
Apparent magnitude (V) 4.279[2]
Spectral type B8 V[3]
U−B color index –0.288[2]
B−V color index –0.062[2]
Radial velocity (Rv)–10.0[4] km/s
Proper motion (μ) RA: +36.89[1] mas/yr
Dec.: –58.99[1] mas/yr
Parallax (π)18.62 ± 0.22[1] mas
Distance175 ± 2 ly
(53.7 ± 0.6 pc)
Absolute magnitude (MV)+0.64[5]
Radius2.7[6] R
Luminosity74[5] L
Surface gravity (log g)4.09 ± 0.08[7] cgs
Temperature11,284 ± 284[6] K
Metallicity [Fe/H]–0.08 ± 0.12[7] dex
Rotational velocity (v sin i)135[8] km/s
Age30–60[9] Myr
Other designations
ι Aqr, 33 Aquarii, BD–14 6209, FK5 828, HD 209819, HIP 109139, HR 8418, SAO 164861.[10]
Database references

Iota Aquarii, Latinized from ι Aquarii, is the Bayer designation for a star in the equatorial constellation of Aquarius. It is visible to the naked eye with an apparent magnitude of +4.279.[2] Based upon parallax measurements made during the Hipparcos mission, the distance to this star is around 175 light-years (54 parsecs).[2]

The spectrum of this star fits a stellar classification of B8 V,[3] showing that this is a B-type main sequence star. It has 2.7[6] times the radius of the Sun and is spinning rapidly with a projected rotational velocity of 135 km/s.[8] A 2010 infrared search for companions around this star was unsuccessful.[9]


  1. ^ a b c d e 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 e Kozok, J. R. (September 1985), "Photometric observations of emission B-stars in the southern Milky Way", Astronomy and Astrophysics Supplement Series, 61: 387–405, Bibcode:1985A&AS...61..387K.
  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,
  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. ^ 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.
  6. ^ a b c Underhill, A. B.; et al. (November 1979), "Effective temperatures, angular diameters, distances and linear radii for 160 O and B stars", Monthly Notices of the Royal Astronomical Society, 189: 601–605, Bibcode:1979MNRAS.189..601U, doi:10.1093/mnras/189.3.601.
  7. ^ a b Wu, Yue; et al. (January 2011), "Coudé-feed stellar spectral library - atmospheric parameters", Astronomy and Astrophysics, 525: A71, arXiv:1009.1491, Bibcode:2011A&A...525A..71W, doi:10.1051/0004-6361/201015014.
  8. ^ a b 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. ^ a b Ehrenreich, D.; et al. (November 2010), "Deep infrared imaging of close companions to austral A- and F-type stars", Astronomy and Astrophysics, 523: A73, arXiv:1007.0002, Bibcode:2010A&A...523A..73E, doi:10.1051/0004-6361/201014763.
  10. ^ "* iot Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-06-30.

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