NGC 6791

NGC 6791 is an open star cluster in the constellation Lyra. Discovered in 1853, it is unusual in that there are three distinct populations of stars in the group. Along with a group of 8 billion year old normal stars there is a group of white dwarfs with a 6 billion year age and a group of white dwarfs with a 4 billion year age. This is contrary to the classic definition of open star clusters such that the stars of such a group are all born from the same molecular cloud and all have the same general age. Needless to say, this cluster has astronomers questioning their understanding of cluster formation and is heavily studied.
 
NGC 6791 was one of the few deep sky objects included in the field of view (FOV) of the Kepler spacecraft during its primary science mission.

(NGC 6791) [C: 56x60s]

Chart generated with Cartes du Ciel