文摘
We study temporal variations in (1) the shadow that the Deep Impact ejecta cast on the nucleus and (2) in the ejecta brightness as it crosses the limb. For the limb-crossing case, we subtract the pre-impact images from the post-impact images to estimate the optical thickness of the ejecta. We also compare the ejecta brightness just before the limb and right after the limb to determine ejecta albedo. The obtained optical depth and albedo of the ejecta during 0.76 - 68.8 s after impact allow revealing bands and azimuthal features in the ejecta. We model the impact crater development to determine the nucleus depth that the material which produced the observed features was excavated from. This allows us to reveal potential structural inhomogeneities in the nucleus, including layering.