9322078 Cravens Comet Shoemaker-Levy 9 is expected to enter the atmosphere of Jupiter on about July 21-23, 1994. Significant amounts of water vapor will be injected into the upper atmosphere of Jupiter. The photochemistry of both the neutral gas and the ionosphere will be greatly altered by the influx of this water vapor or the atomic oxygen generated by the dissociation of the water. The odd oxygen (i.e., oxygen or water vapor or the hydroxyl radical) associated with the cometary water influx alters the ion chemistry by removing ionized hydrogen ions, which also has the effect of reducing the ionospheric electron density because ionized hydrogen is ordinarily the main ion species in the Jovian ionosphere. The oxygen atoms from the dissociation of the cometary water will also react with the methyl radical and eventually form carbon monoxide deeper in the atmosphere. The PI has a numerical model that was originally developed to study the effects of odd oxygen on the auroral ionosphere of Jupiter. He proposes to adapt this model to study the effects of comet Shoemaker-Levy 9 on the thermosphere and ionosphere of Jupiter. These effects (e.g., severe reduction of electron density) will be both global and significant even a couple of years after the comet impact which will allow the Galileo spacecraft to study the recovery from this event. ***
