HST PROPER MOTIONS AND STELLAR DYNAMICS IN THE CORE OF 47 TUCANAE
Dean McLaughlin (STScI)
We have obtained velocities on the plane of the sky for more than 10,000
stars in the central regions of the Galactic globular cluster 47 Tucanae,
from multiple images of the cluster taken with the Hubble Space Telescope
between 1995 and 2002. This is the largest velocity dataset obtained to
date for any star cluster. I will describe how we are using it to (1)
determine a precise distance to 47 Tuc, in a way independent of
stellar-evolution theory; (2) search for any anomalously high-velocity
stars in the cluster core, such as might be produced by close stellar
encounters in this high-density environment; (3) place an upper limit on
the possible size of any putative central mass concentration such as a
black hole; and (4) test directly the standard (King-Michie) dynamical
models of globular clusters.
