Mass segregation in star clusters is not energy equipartition
  Mass segregation in star clusters is often thought to indicate the onset of
energy equipartition, where the most massive stars impart kinetic energy to the
lower-mass stars and brown dwarfs/free floating planets. The predicted net
result of this is that the centrally concentrated massive stars should have
significantly lower velocities than fast-moving low-mass objects on the
periphery of the cluster. We search for energy equipartition in initially
spatially and kinematically substructured N-body simulations of star clusters
with N = 1500 stars, evolved for 100 Myr. In clusters that show significant
mass segregation we find no differences in the proper motions or radial
velocities as a function of mass. The kinetic energies of all stars decrease as
the clusters relax, but the kinetic energies of the most massive stars do not
decrease faster than those of lower-mass stars. These results suggest that
dynamical mass segregation -- which is observed in many star clusters -- is not
a signature of energy equipartition from two-body relaxation.
