The prominent open cluster the Pleiades, in the constellation Taurus, has been recognized as a group of stars since antiquity, while the Hyades (which also form part of See more

Open clusters range from very sparse clusters with only a few members to large agglomerations containing thousands of stars. They usually consist of quite a distinct dense core, … See more

Because open clusters tend to be dispersed before most of their stars reach the end of their lives, the light from them tends to be dominated by the young, hot blue stars. These … See more

When a Hertzsprung–Russell diagram is plotted for an open cluster, most stars lie on the main sequence. The most massive stars have begun to … See more

The formation of an open cluster begins with the collapse of part of a giant molecular cloud, a cold dense cloud of gas and dust containing up to many thousands of times the mass of the Sun. These clouds have densities that vary from 10 to 10 molecules of See more

There are over 1,100 known open clusters in our galaxy, but the true total may be up to ten times higher than that. In spiral galaxies, open clusters are largely found in the spiral arms … See more

Many open clusters are inherently unstable, with a small enough mass that the escape velocity of the system is lower than the average See more