“An open cluster is a type of star cluster made of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way galaxy, and many more are thought to exist. They are loosely bound by mutual gravitational attraction and become disrupted by close encounters with other clusters and clouds of gas as they orbit the Galactic Center. This can result in a migration to the main body of the galaxy and a loss of cluster members through internal close encounters. Open clusters generally survive for a few hundred million years, with the most massive ones surviving for a few billion years.”
Messier 45 the Pleiades or "Seven Sisters" from Lake Mineral Wells State Park in Mineral Wells, TX.
The Double Cluster in Perseus & Comet PANSTARRS C/2017 T2.
Venus in Taurus with the open clusters The Hyades (left) and The Pleiades (M45) just to the right of the planet Venus in April 2023.
Open clusters M35 and NGC 2158 in Gemini