Lambda Arietis

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Lambda Arietis
Diagram showing star positions and boundaries of the Aries constellation and its surroundings
Cercle rouge 100%.svg
Location of λ Arietis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aries
Right ascension 01h 57m 55.71647s[1]
Declination +23° 35′ 45.8295″[1]
Apparent magnitude (V) 4.79[2] (4.95/7.75)[3]
Spectral type F0 V + G1 V[3]
U−B color index +0.09[2]
B−V color index +0.28[2]
R−I color index 0.16
Radial velocity (Rv)-1.4[4] km/s
Proper motion (μ) RA: -92.55[1] mas/yr
Dec.: -13.25[1] mas/yr
Parallax (π)25.32 ± 0.30[1] mas
Distance129 ± 2 ly
(39.5 ± 0.5 pc)
λ Ari A
Surface gravity (log g)3.88[5] cgs
Temperature7,177[5] K
Metallicity [Fe/H]+0.01[5] dex
Rotational velocity (v sin i)107[6] km/s
λ Ari B
Surface gravity (log g)3.88[5] cgs
Temperature5,929[5] K
Metallicity [Fe/H]–0.03[5] dex
Other designations
9 Arietis, BD+22 288, HD 11973, HIP 9153, HR 569, SAO 75051, GC 2366, ADS 1563, CCDM 01580+2336.[7]
Database references

Lambda Arietis (λ Ari, λ Arietis) is the Bayer designation for a double star in the northern constellation of Aries. Based upon an annual parallax shift of 25.32 arcseconds, this system is approximately 129 light-years (40 parsecs) distant from Earth. The pair have a combined apparent visual magnitude of 4.79,[2] which is bright enough to be viewed with the naked eye. Because the yellow secondary is nearly three magnitudes fainter than the white primary, they are a challenge to split with quality 7× binoculars and are readily resolvable at 10×.[8]

The brighter component is an F-type main sequence star with a visual magnitude of 4.95 and a stellar classification of F0 V.[3] At an angular separation of 37.4 arcseconds is fainter, magnitude 7.75 companion. This is a G-type main sequence star with a classification of G1 V.[3]


  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:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99), Bibcode:1966CoLPL...4...99J. 
  3. ^ a b c d 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, arXiv:0806.2878Freely accessible, Bibcode:2008MNRAS.389..869E, 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 e f Soubiran, C.; Le Campion, J.-F.; Cayrel de Strobel, G.; Caillo, A. (June 2010), "The PASTEL catalogue of stellar parameters", Astronomy and Astrophysics, 515: A111, arXiv:1004.1069Freely accessible, Bibcode:2010A&A...515A.111S, doi:10.1051/0004-6361/201014247. 
  6. ^ Royer, F.; Zorec, J.; Gómez, A. E. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv:astro-ph/0610785Freely accessible, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224. 
  7. ^ "lam Ari". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-08-07. 
  8. ^ Harrington, Philip S. (2010), Cosmic Challenge: The Ultimate Observing List for Amateurs, Cambridge University Press, p. 113, ISBN 0521899362