The Hubble and James Webb space telescopes joined forces to study Terzan 5, a peculiar cluster containing at least four distinct stellar populations--formed 12.5 billion, 4.7 billion, 3.8 billion, and 2.5 billion years ago, respectively. This demonstrates that Terzan 5 is not a globular star cluster, as originally classified. Instead, it is a fossil fragment of the galactic bulge: an autonomous, self-enriched stellar system featuring multiple stellar populations of varying ages and iron abundances.
NASA
