What is a open cluster?
Open stellar clusters are groups of stars formed from the same molecular cloud, without structure and generally asymmetric. They are also called galactic clusters, as they can be found throughout the galactic plane.
How is an open cluster formed?
Its formation begins with the collapse of part of a large molecular cloud. Once the molecular cloud has begun to collapse, it fragments into smaller and smaller groups, resulting in the formation of several thousand stars. Once the formation of stars has begun, the hottest and most massive will emit huge amounts of ultraviolet radiation. This radiation rapidly ionizes the surrounding gas in the large molecular cloud, causing a region to form. The stellar winds of the most massive stars, together with the radiation pressure, direct the gases from the cloud outwards and expel them over time; after a few million years, the cluster will experience its first supernova, helping to expel gas from the system. After several tens of millions of years, the cluster is free of gas and star formation has ended.
