The Pleiades open star cluster, M45, is relatively close to the Earth, at about 400 light-years away, and is bright in the winter skies. There are actually over 1000 stars in the group, but the dominant members are the hot B-type stars which dominate this image. The stars in the cluster are all moving together through space.

At this time they are passing through a cloud of interstellar dust and this is scattering and reflecting the light from the brighter stars, an effect called a reflection nebula.