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Polaris
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Polaris

Bright star closest to the north celestial pole, and the brightest star in the constellation Ursa Minor. Its position is indicated by the ‘pointers’ in Ursa Major. Polaris is a yellow supergiant about 500 light years away from the Sun. It is also known as Alpha Ursae Minoris.

It currently lies within 1° of the north celestial pole; precession (Earth's axial wobble) will bring Polaris closest to the celestial pole (less than 0.5° away) in about AD 2100. Then its distance will start to increase, reaching 1° in 2205 and 47° in 28000. Other bright stars that have been, or will be close to the north celestial pole are Alpha Draconis (2800 BC), Gamma Cephei (AD 4000), Alpha Cephei (AD 7000), and Vega (AD 14000).

Polaris is a Cepheid variable whose magnitude varies between 2.1 and 2.2 over 3.97 days. It has a faint (magnitude 9) companion, and possibly several others.



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