  The Deep Impact encounter with the nucleus of 9P/Tempel ejected small grains
(a <~ 10 micron) into the comet's coma, evidenced by thermal emission from
small dust grains at mid-infrared wavelengths (~10 micron) and dynamical
simulations of optical images. Meteor-sized particles (a >~ 100 micron) ejected
by the impact will likely have the lowest ejection velocities and will weakly
interact with solar radiation pressure. Therefore, large particles may remain
near the nucleus for weeks or months after ejection by Deep Impact. We present
initial highlights of our Spitzer Space Telescope/MIPS 24 micron camera program
to image comet 9P/Tempel at 30, 80, 420, and 560 days after the Deep Impact
encounter. The MIPS data, combined with our dynamics model, enable detection of
large dust grains potentially ejected by Deep Impact.

Astrophysics