Open Cluster

An open cluster is a group of stars that formed together from the same giant cloud of gas and dust, clustering in a loose, irregular pattern. These stars are gravitationally bound but spread out over a relatively small area of space, often containing a few dozen to a few thousand stars. Open clusters are typically found in the spiral arms of galaxies like the Milky Way and are relatively young, usually a few million to a few billion years old. They are valuable for studying stellar evolution since their stars are roughly the same age and composition.