DYNAMIC RESPONSE OF JUPITER'S ATMOSPHERE TO THE IMPACT OF COMET SHOEMAKER-LEVY 9

DURING the period 18-24 July 1994, over 20 fragments of comet Shoemaker-Levy 9 will collide with Jupiter1-3. The thermal and condensation signatures of inertia-gravity waves emanating from the impact sites will, if detectable, provide valuable insight into the stratification of Jupiter's atmosphere. We report here simulations of the event using a global multi-layer model4 of Jupiter's atmosphere and a range of impact kinetic energies (10(27)-10(30) erg) that allows for the uncertainties in the sizes and densities of the comet fragments5-8. The resulting inertia-gravity waves give rise to temperature perturbations in the range 0.004-1.2 K. The signature of the larger impacts may be detectable by thermal infrared imaging, and even weak signals may be detectable if one allows for the fact that the waves propagate in coherent rings centred on each impact site. Our simulations also indicate that a small vortex should form in the atmosphere following each impact, but that these will be sheared apart by the zonal winds within a few weeks.