Polaris (α UMi, α Ursae Minoris, Alpha Ursae Minoris, commonly North Star, Northern Star or Pole Star, also Lodestar, sometimes Guiding star) is the brightest star in the constellation Ursa Minor. It is very close to the north celestial pole, making it the current northern pole star.
Based on measurements from the Hipparcos astrometry satellite, Polaris is estimated to be at a distance of about 434 light-years from Earth. It is a multiple star, c...
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Polaris (α UMi, α Ursae Minoris, Alpha Ursae Minoris, commonly North Star, Northern Star or Pole Star, also Lodestar, sometimes Guiding star) is the brightest star in the constellation Ursa Minor. It is very close to the north celestial pole, making it the current northern pole star.
Based on measurements from the Hipparcos astrometry satellite, Polaris is estimated to be at a distance of about 434 light-years from Earth. It is a multiple star, consisting of the main star α UMi A, two smaller companions, α UMi B and α UMi Ab, and two distant components α UMi C and α UMi D. α UMi B was discovered in 1780 by William Herschel.
α UMi A is a six solar mass F8 supergiant (Ib) or bright giant (II). The two smaller companions are: α UMi B, a 1.5 solar mass F3 main sequence star orbiting at a distance of 2400 AU, and α UMi Ab (or P), a very close dwarf with an 18.8 AU radius orbit. There are also two distant components α UMi C and α UMi D.
Polaris B can be seen even with a modest telescope and...
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