HST Results on Globular Clusters 

Ivan R. King, U. C. Berkeley

HST offers two advantages in observations of globular clusters:
resolving the dense central regions, and reaching fainter stars than
have yet been observed from the ground.  Both these advantages combine
when we wish to observe faint stars at the centers of globulars.  This
paper will contrast the centers of globular clusters with the outer
parts and will discuss dynamical modeling that ties the various regions
together.  First, it will be shown that multimass King models can
adequately fit the brightness profiles of post-core-collapse clusters.
Then a strong mass segregation will be shown in observations of NGC
6397, and it will be shown to be well fitted by such a model.  Finally,
the low-mass-star depletion of NGC 6397 (to be described by Piotto) will
be discussed in the context of the dynamics of evaporation and of
Galactic tidal shocks.