starcluster

Star clusters are gravitationally bound assemblies of stars that originated from the same giant molecular cloud and therefore share a common age and chemical composition. They are valuable for studying stellar evolution, the structure of galaxies, and the history of star formation.

Star clusters are commonly divided into two main types: open clusters and globular clusters. Open clusters are relatively young, contain tens to thousands of stars, and have loose, irregular shapes. They reside primarily in the disks of galaxies and are often found near star-forming regions. Their color-magnitude diagrams show a clear main sequence corresponding to a single age. Notable examples include the Pleiades and the Hyades in the Milky Way.

Globular clusters are much older, densely packed, and spheroidal, containing hundreds of thousands to millions of stars. They orbit the halos of galaxies at larger galactic distances and typically exhibit low metallicities, reflecting early chemical enrichment. In the Milky Way, examples include Omega Centauri, 47 Tucanae, and M13. Globular clusters provide stringent tests for stellar evolution models and offer insights into the early assembly history of their host galaxies.

Star clusters are observed in many galaxies beyond the Milky Way, including the Large Magellanic Cloud and the Andromeda Galaxy. They help trace star formation rates, chemical evolution, and dynamical processes across cosmic time. Some clusters dissolve over time due to internal dynamics and tidal forces, while others remain as long-lived tracers of their galactic environments.