56 Arietis

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56 Arietis
Observation data
Epoch J2000      Equinox J2000.0 (ICRS)
Constellation Aries
Right ascension 03h 12m 14.24670s[1]
Declination +27° 15′ 25.0847″[1]
Apparent magnitude (V) 5.79[2]
Spectral type B9pSi[3]
U−B color index –0.42[2]
B−V color index –0.12[2]
Variable type SX Ari
Radial velocity (Rv) +18.0[4] km/s
Proper motion (μ) RA: +12.39[1] mas/yr
Dec.: –18.57[1] mas/yr
Parallax (π) 6.49 ± 0.76[1] mas
Distance approx. 500 ly
(approx. 150 pc)
Absolute magnitude (MV) +0.25[5]
Mass 3.16 ± 0.17[5] M
Radius 2.3 ± 0.3[5] R
Luminosity 110[5] L
Surface gravity (log g) 4.36 ± 0.12[5] cgs
Temperature 12,445[5] K
Rotation 0.7278972 days[5]
Other designations
SX Arietis, BD+26 523, HD 19832, HIP 14893, HR 954, SAO 75788.[6]
Database references

56 Arietis (abbreviated 56 Ari) is a star in the northern constellation of Aries. 56 Arietis is the Flamsteed designation. It is faintly visible to the naked eye with an apparent visual magnitude is 5.79.[2] The estimated distance to this star is approximately 500 light-years (150 parsecs). This is a magnetic, chemically peculiar star of the silicon type and it has a rapid rotation period of 17.5 hours.[7]

56 Arietis is also known by its variable star designation SX Arietis.[6] 56 Arietis is the prototype of a class of variable stars known as SX Arietis variables, which are rotationally variable stars with strong magnetic fields.


  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 Nicolet, B. (1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", Astronomy and Astrophysics Supplement Series, 34: 1–49, Bibcode:1978A&AS...34....1N. 
  3. ^ Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819. 
  4. ^ Bonsack, Walter K. (February 1958), "Wavelength Variations in the Spectrum of 56 ARIETIS", Publications of the Astronomical Society of the Pacific, 70 (412): 90, Bibcode:1958PASP...70...90B, doi:10.1086/127180. 
  5. ^ a b c d e f g North, P. (June 1998), "Do SI stars undergo any rotational braking?", Astronomy and Astrophysics, 334: 181–187, arXiv:astro-ph/9802286Freely accessible, Bibcode:1998A&A...334..181N. 
  6. ^ a b "SX Ari -- Variable Star of alpha2 CVn type", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-07-18. 
  7. ^ Ziznovsky, J.; Schwartz, P.; Zverko, J. (January 2000), "The Variable Light Curve of 56 Arietis", Information Bulletin on Variable Stars, 4835: 1, Bibcode:2000IBVS.4835....1Z. 

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