• Polaris

  Polaris is a star in Ursa Minor.

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  Type            Yellow-white supergiant
  Constellation   Ursa Minor
  Magnitude       2.0
  Spectral type   F7:Ib-II
  Distance        431 light years
  Double star     components 18.4″ apart
  You need        naked eye from a dark sky

  Known as
  Bayer           α UMi
  Yale            HR 424

  Physical
  Radius          46 times the Sun

  More information about Polaris

  Polaris sits within one degree of the point in the sky that the Earth's
  axis points at, so as the sky turns through the night it barely moves
  while everything else wheels around it. That is a temporary arrangement.
  The axis slowly traces out a circle taking about 26,000 years, which
  shifts the pole roughly a degree every 72 years, so the job passes from
  one star to another: Thuban held it 4,700 years ago, Vega will hold it
  in 12,000, and Polaris has had it for only about a thousand years. It is
  not one star either: it is three, and the brightest of them swells and
  shrinks on a four-day cycle.

  Etymology
  From        Latin
  Reading     stella polaris
  Literally   the pole star

  Bayer lettered the stars of each constellation in his Uranometria of
  1603, in order of brightness. He was working from Tycho's magnitudes by
  eye, and the order he recorded is often wrong.

  First published in 1930 by Yale astronomer Frank Schlesinger, and
  maintained since, the Yale Bright Star Catalogue lists every star down
  to magnitude 6.5. It contains 9,110 stars.

  where it is tonight:  skymap.sh/Polaris