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E. Asphaug (UCSC), P. Schenk (LPI), J. M. Moore, D. Morrson (NASA Ames), C. R. Chapman, W. J. Merline (SwRI)
Comet SL9's tidal disruption near Jupiter, and Voyager images of split-comet catenae on Ganymede and Callisto, led many to anticipate dozens of catenae in Galileo high resolution coverage. There appear however to be no small catenae, suggesting that small comets are either underabundant or strong.
At larger scales, some new catenae have been discovered, which we report on. One is shown below; at ~43 km it is the smallest so far imaged, with a progenitor diameter approximately ~1 km. This catena (from G2 Nippur Sulcus) lies on the "forbidden" antijovian hemisphere, approximately 400 km from the center of the penepalimpsest Epigeous (23N, 181W, ~210 km). Either Ganymede has rotated since the catena’s emplacement, or it is a non-tidal secondary chain. The catena appears much younger than Epigeous, and the chain aligns well outside a line tangential to the basin. The morphology strongly resembles well-characterized tidal disruption catenae.