Pleiades

The Pleiades (M45, the "Seven Sisters") — the brightest and one of the nearest open clusters, about 440 light-years away in Taurus. Over a thousand young stars roughly 100 million years old, dominated by hot blue B-type members easily visible to the naked eye. The blue haze around them is an unrelated dust cloud the cluster is drifting through, scattering the starlight, not leftover material from their birth.