EUVE OBSERVATIONS OF JUPITER DURING THE IMPACT OF COMET SHOEMAKER-LEVY-9

The Extreme Ultraviolet Explorer (EUVE) satellite conducted extensive observations of the jovian system before, during, and after the impact of the fragments of comet Shoemaker-Levy 9 in July 1 994. About 2 to 4 hours after the impacts of several of the larger fragments, the brig htness of the neutral helium (He I) resonance line at 58.4 nanometers temporarily increased by a factor of about 10. The transient 58.4-nano meter brightenings are most simply explained by resonant scattering of sunlight from the widespread high-altitude remnants of the larger imp act plumes. Other possible sources of emission, such as electron impac t excitation of He or radiative recombination of He+, may contribute t o the observed signal.