  Sub-arcsecond scale Keck images of the young A1V star, 49 Ceti, resolve
emission at lambda = 12.5 and 17.9 microns from a disk with long axis at PA 125
pm 10 degrees and inclination phi = 60 pm 15 degrees . At 17.9 microns, the
emission is brighter and more extended toward the NW than the SE. Modeling of
the mid-infrared images combined with flux densities from the literature
indicate that the bulk of the mid-infrared emission comes from very small
grains (a ~ 0.1 microns) confined between 30 and 60 AU from the star. This
population of dust grains contributes negligibly to the significant excess
observed in the spectral energy distribution. Most of the non- photospheric
energy is radiated at longer wavelengths by an outer disk of larger grains (a ~
15 microns), inner radius ~ 60 AU, and outer radius ~ 900 AU. Global properties
of the 49 Cet disk show more affinity with the Beta Pic and HR 4796A disks than
with other debris disks. This may be because they are all very young (t < 20
Myr), adding strength to the argument that they are transitional objects
between Herbig Ae and "Vega-like" A stars with more tenuous circumstellar
disks.
