What is the main characteristic of an open cluster compared to a globular cluster?

Open clusters are characterized by being generally younger and less dense compared to globular clusters. Open clusters typically contain a relatively small number of stars, often ranging from a few dozen to a few thousand, and these stars are usually in a loose formation. They are often found in the disk of the galaxy, where new star formation is more active, giving rise to younger stars that can be only a few million years old, while globular clusters contain older stars that can be billions of years old.

In contrast to open clusters, globular clusters are much more densely packed with stars and can contain hundreds of thousands to millions of stars. They are usually found in the halo of galaxies and consist primarily of older stars, often featuring red giants. This difference in age and density is a significant characteristic that distinguishes open clusters from globular clusters.