Globular Cluster 47 Tucanae
The heart of the giant globular star cluster 47 Tucanae reveals the glow of 200,000 stars. In this cluster, Hubble spied a parade of young white dwarfs starting their 40-million-year migration away from the core. In globular clusters, lower mass stars rob momentum from more massive stars. Heavier stars sink to the cluster's core as their orbits slow, while lighter stars pick up speed and move across the cluster to the edge.
Acknowledgment: J. Mack (STScI) and G. Piotto (University of Padova, Italy)