  The face-on disk around TW Hya is imaged in scattered light at wavelengths of
1.1 and 1.6 micron using the coronagraph in the Near Infrared Camera and Multi
Object Spectrometer aboard the Hubble Space Telescope. Stellar light scattered
from the optically thick dust disk is seen from 20-230 AU. The surface
brightness declines as a power law of r^(-2.6+/-0.1) between 45 and 150 AU. The
scattering profile indicates that the disk is flared, not geometrically flat.
The disk, while spatially unresolved in thermal radiation at wavelengths of 12
and 18 micron in observations from the W. M. Keck Observatory, shows amorphous
and crystalline silicate emission in its spectrum. A disk with silicate grains
of a ~1 micron in size in its surface layers can explain the shape of the
mid-infrared spectrum. Much larger grains in the disk interior are necessary to
fit the millimeter-wave spectral energy distribution, and hence grain growth
from an original interstellar size population may have occurred.
