  Model surface brightness profiles based on Fokker-Planck simulations have
been used to assess the high resolution surface brightness profile of the
globular cluster NGC 6397 of Lauzeral et al. (1992). The profile is well fitted
by the model in the maximum-expansion phase of a gravothermal oscillation with
a core radius of 0.06 pc (6''), but an unresolved core cannot be ruled out. A
core this size is also expected in highly evolved clusters including
significant numbers of primordial binaries. A more massive cluster will provide
better statistics, as would star counts. The greater distance of the other
globular clusters and the requirements of star counting will demand very high
resolution observations to definitively resolve cores this size.
