Open cluster Trumpler 5 in Monoceros
author: Anglo-Australian Observatory/David Malin Images/Novapix
reference: a-aou97-00001
Image Size 300 DPI: 40 * 51 cm
As they age, open clusters of stars begin to lose their identity. This is partly because the brighter members tend to self-destruct as supernovae, and, though the group members share a common motion through space, they are only loosely bound. Thus stars drift away from the cluster in a process that accelerates with time. However, some clusters are big enough to retain their identity much longer than usual, and Trumpler 5 is one such. Its age is estimated to be 125 million years, and it must have been a spectacular sight in its youth. It seems to be at the edge of the Monoceros molecular cloud, where star formation is continuing new generations of young clusters.
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