Description: Star clusters are groups of stars where all the constituent stars are located in the same area of the sky, with similar distance to us, similar chemical composition, and motion, and are often approximately the same age. The stars in the cluster are likely to have been formed from the same parent cloud of gas. The density distribution could either be centrally concentrated and spherical, or have more complex shapes. They are broadly categorized into two types: Open star clusters and globular clusters. Open clusters are younger (few million years to about 4–5 billion years), have memberships of hundreds to thousands of stars, and could have associated gas and dust remnants from the parent cloud. In the Milky Way, open clusters are typically found in the galactic disk. Globular clusters are among the oldest entities with most being more than 10 billion years old. They are centrally concentrated, spherical shaped clusters containing thousands to millions of stars. In the Milky Way, globular clusters are typically found in the galactic halo.

Related Terms:

• Galactic Disk
• Galactic Halo
• Globular Cluster
• Milky Way
• Star
• Star Formation
• Open Cluster

Term and definition status: This term and its definition have been approved by a research astronomer and a teacher

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