Seven Sisters: Pleiades

The Seven Sisters, also called the Pleiades or M45, is an open star cluster located about 400 light years away towards the constellation Taurus. It is about 13 light years across and is one of the brightest and closest star clusters to us.

The cluster contains over 3000 stars, most of which are considered middle aged. Surrounding the brighter stars are reflection nebulae, gas and dust reflecting the light from the stars. Also buried in the cluster are faint, low mass brown dwarf stars.

Image from National Geographic, information from NASA.

The Pleiades

Perhaps the most famous star cluster on the sky, the Pleiades can be seen without binoculars from even the depths of a light-polluted city. Also known as the Seven Sisters and M45, the Pleiades is one of the brightest and closest open clusters. The Pleiades contains over 3000 stars, is about 400 light years away, and only 13 light years across. Quite evident in the above photograph are the blue reflection nebulae that surround the brighter cluster stars. Low mass, faint, brown dwarfs have also been found in the Pleiades.

Image credit: Marco Lorenzi

The Pleiades open cluster, or Messier 45. A collection of Hot, Blue Stars that formed together from the same nebula.

At 444 lightyears away, t’s one of the closest clusters to our Solar System and is just visible to the Naked Eye on most nights in Northern-Hemisphere Winter, making it an easy target for any Northern-Hemisphere Astronomer. 

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