A study published in Astronomy & Astrophysics has identified four previously unknown primordial open cluster (OC) groups in the Milky Way.
Open clusters, loose assemblies of stars born from the same giant molecular cloud (GMC), are typically considered to form in isolation. However, the newly discovered OC groups consist of multiple member clusters originating from the same GMC, formed through sequential star formation processes.
Notably, two of these groups, labeled G1 and G2, appear to have formed via a hierarchical mechanism triggered by multiple supernova (SN) explosions.