21 Persei

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21 Persei
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Perseus
Right ascension 02h 57m 17.28220s [1]
Declination +31° 56′ 03.1871″ [1]

21 Persei is an star in the constellation Perseus. Its apparent magnitude is 5.10. Located around 98.03 parsecs (319.7 ly) distant, it is an hot blue star of spectral type B9.[1] The star is an Alpha2 Canum Venaticorum variable, meaning that the star has a strong magnetic field chromium, silicon, and strontium spectral lines. 21 Persei's period is approximately 2.88 days[2]


  1. ^ a b c "LT Persei". SIMBAD Astronomical Database. Centre de Données astronomiques de Strasbourg. Retrieved 28 December 2013. 
  2. ^ Catalano, F. A.; Renson, P.; Leone, F. "Third supplement to the catalogue of observed periods of Ap stars". Astronomy and Astrophysics Supplement Series 98 (2): 269–273. Bibcode:1993A&AS...98..269C.