Are the Fragments of Comet Shoemaker-Levy 9 Swarms of Meter-Sized Planetesimals?
T.W.Rettig (Univ Notre Dame), M.J.Mumma (NASA/Goddard), S.C.Tegler, J.Hahn (Univ Notre Dame) The tidally fragmented comet S-L 9 presently exhibits 21 major concentrations of material (sub-nuclei) as well as extended dust wings. Comet S-L 9 is the first inactive comet observed to fragment under the influence of tidal forces alone. In contrast to the analysis of Weaver et al. (1994) where each subnucleus is interpreted to contain a compact body 3-4 km in diameter, we investigate the possibility that each subnucleus is composed of tidally fragmented `swarms’ of $\sim$ 50-m sized planetesimals. Our swarm model for the subnuclei suggests the upcoming impact of comet S-L 9 with Jupiter will result in vaporization of these bolides high in the Jovian stratosphere. Recent models of planetesimal accumulation in the solar nebula favor development of a bi-modal size distribution before the onset of gravitational instability triggers formation of larger bodies (Weidenschilling 1993).
