Dimensions and Fragmentation of the Nuclei of Comet Shoemaker-Levi 9

Central regions on the digital maps of 13 nuclear condensations of Comet Shoemaker-Levi 9, obtained with the Planetary Camera of the Hubble Space Telescope on January 27, March 30, and July 4, 1994, have been analyzed with the aim to identify the presence of distinct, major fragments in each condensation, to deconvolve their contributions to the signal that also includes the contribution from a surrounding cloud of dust (modeled as an extended source, using two different laws), to estimate the dimensions of the fragments and to study their temporal variations, and to determine the spatial distributions of the fragments as projected on to the plane of the sky. The deconvolution method applied is described and the results of the analysis are summarized, including the finding that sizable fragments did survive until the time of atmospheric entry. This result does not contradict evidence of the comet's continuing, apparently spontaneous fragmentation, which still went on long after the extremely close approach to Jupiter in July 1992 and which, because of the Jovian tidal effects, may have intensified in the final days before the crash on Jupiter. Since the developed approach is based on certain premises and involves approximations, the results should be viewed as preliminary and the problem should be the subject of further investigation.