SPACE.com — Mass Migration: How Stars Move in Crowd
The stellar residents of the jam-packed celestial cities known as globular clusters employ a traffic system that causes lightweight stars to zoom to the city edges while keeping giants centrally located, astronomers have concluded.
The study, detailed in the September issue of the Astrophysical Journal Supplement Series, gives the first direct evidence of such sorting, called “mass segregation,” a process long suspected to occur in globular clusters but never observed.
A globular cluster is a dense collection of 10,000 to more than a million stars in a region spanning just 10 to 30 light-years. The nearest star to our Sun, for comparison, is more than 4 light-years away.
Researchers analyzed 47 Tucanae, the second largest cluster in the Milky Way’s galactic neighborhood, and determined the cluster sorts out stars according to their masses. Due to the associated gravitational pull, heavier stars slow down and sink to the cluster’s core, while lighter stars pick up speed and zip out to the cluster’s periphery [Read on]