Context: Recently, a Study showing stars of varied ages can co-exist in open clusters, provides clue to stellar evolution in the Milky Way Galaxy.
About Star Clusters

• Stars in the Milky Way Galaxy are formed from the molecular clouds present in the galaxy.
• Star clusters are important clues to understand the mechanism of star formation because it is believed that a majority of stars in the Milky Way are formed in star clusters.
• Star clusters are groups of stars which are gravitationally bound.
• Open star clusters are a system of stars bound by gravity in which stars are born from the same molecular clouds.
• All the stars in a cluster follow the evolutionary sequence as per their initial masses at the time of formation of these stars.
• Open clusters are also important in probing the formation and evolution of the Milky Way Galaxy as they are distributed throughout the Galactic disk.

About Star clusters in Milky way galaxy

• Astronomers at the Aryabhatta Research Institute of Observational Sciences (ARIES), an autonomous science institute under the Department of Science and Technology (DST) Govt. of India, have found that stars of varied ages can co-exist in open clusters. This challenges earlier understanding that stars in an open cluster have the same age.
• The scientists measured the light from three poorly studied open clusters NGC 381, NGC 2360, and Berkeley 68 (observed using the 1.3-m telescope at Devasthal Observatory situated in Nainital) for studying the evolution of stars in these clusters.
• They found two different stellar evolutionary sequences in the cluster NGC 2360, which has been observed in very few open clusters in the Milky Way Galaxy until now.
• Other than the stellar evolution, the researchers also studied the dynamical evolution of these clusters for the first time.
• The mass distributions of stars belonging to the clusters have shown the preferential distribution of massive stars in the inner part of the clusters while low mass stars are found towards outer region of the clusters.
• It is believed that some of the very low mass stars have in fact, left their parent clusters and may be roaming as a free star like our own Sun.
• Their study lent important insight about the stellar and dynamical evolution of these clusters.