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Session 42 - Solar Systems.
Display session, Tuesday, January 16
North Banquet Hall, Convention Center

[42.11] Dust Outflow Velocity for Comet Shoemaker-Levy 9

T. W. Rettig, G. Sobczak, J. M. Hahn (U. Notre Dame)

Tidal dispersal of the dust comae of the \ 21 fragments of comet Shoemaker-Levy 9 (S-L9) became very pronounced in the Hubble Space Telescope images during the weeks prior to impact with Jupiter (Rettig et al. 1994, Weaver et al. 1994). The amount of tidal dispersal experienced by the dust comae is measured by calculating the flux as a function of distance from the center of the comae in both the jovian and transverse directions. Dividing the jovian by the transverse brightness profiles yields a quantity with approximately constant slope which we define as the J/T index. The scale of this tidal dispersal is a function of the dust grain outflow velocity and distance from Jupiter. Monte Carlo tidal dust models for various outflow velocities are used to constrain the dust outflow velocity to 0.4 +/-0.1 meters/sec. In contrast to previous analyses suggesting S-L9 was an inactive comet (Sekanina et al. 1994, 1995, Chernova et al. 1995), both the tidally elongated dust comae and the dust outflow velocity measurements point to S-L9 as having been an active comet. The models also show the brightness of the inner comae decrease as the fragments approach Jupiter, some of this decrease can be explained by the increasing dispersal of the comae dust.

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