stellar association

A stellar association, or moving group, is a very loose star cluster, looser than both open clusters and globular clusters. Stellar associations will normally contain from 10 to 100 or more stars. The stars share a common origin, but have become gravitationally unbound and are still moving together through space. Moving groups are primarily identified by their common movement vectors and ages. Identification by chemical composition is also used to factor in moving group memberships.
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