Iota Arietis

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Iota Arietis
Diagram showing star positions and boundaries of the Aries constellation and its surroundings
Cercle rouge 100%.svg

Location of ι Arietis (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Aries
Right ascension 01h 57m 21.05476s[1]
Declination +17° 49′ 03.1202″[1]
Apparent magnitude (V) 5.117[2]
Spectral type K1 Vp[3]
U−B color index +0.700[2]
B−V color index +0.921[2]
Radial velocity (Rv) –4.9[4] km/s
Proper motion (μ) RA: +34.76[1] mas/yr
Dec.: –22.95[1] mas/yr
Parallax (π) 6.27 ± 0.33[1] mas
Distance 520 ± 30 ly
(159 ± 8 pc)
Absolute magnitude (MV) –0.4[5]
Surface gravity (log g) 2.42[5] cgs
Temperature 4,235[5] K
Metallicity [Fe/H] –0.37[5] dex
Other designations
8 Arietis, BD+17 289, FK5 2132, HD 11909, HIP 9110, HR 563, SAO 92721.[6]
Database references

Iota Arietis (ι Ari, ι Arietis) is the Bayer designation for a binary star system in the northern constellation of Aries. It has an apparent visual magnitude of 5.117;[2] bright enough to be dimly seen with the naked eye. Parallax measurements made during the Hipparcos mission yield an estimated distance of 520 light-years (160 parsecs) from Earth.[1]

This is a spectroscopic binary system with an orbital period of 1,568 days (4.3 years) and an eccentricity of 0.36. The primary is a K-type main sequence star with a stellar classification of K1 Vp. (The 'p' indicates some type of peculiarity with the spectrum.) The companion is a suspected white dwarf.[3]


  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, Bibcode:2007A&A...474..653V, arXiv:0708.1752Freely accessible, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d Jennens, P. A.; Helfer, H. L. (September 1975), "A new photometric metal abundance and luminosity calibration for field G and K giants.", Monthly Notices of the Royal Astronomical Society, 172: 667–679, Bibcode:1975MNRAS.172..667J, doi:10.1093/mnras/172.3.667. 
  3. ^ a b Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, Bibcode:2008MNRAS.389..869E, arXiv:0806.2878Freely accessible, doi:10.1111/j.1365-2966.2008.13596.x. 
  4. ^ Wilson, Ralph Elmer (1953), General Catalogue of Stellar Radial Velocities, Washington: Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W. 
  5. ^ a b c d Helfer, H. L.; Wallerstein, George (August 1968), "Abundances in K-Giant Stars. II. a Survey of Field Stars", Astrophysical Journal Supplement, 16: 1, Bibcode:1968ApJS...16....1H, doi:10.1086/190169. 
  6. ^ "iot Ari -- Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-08-04. 

External links[edit]