FAR-UV EMISSIONS FROM THE SL9 IMPACTS WITH JUPITER

Observations with the International Ultraviolet Explorer (IUE) during the impacts of the fragments of comet D/Shoemaker-Levy 9 with Jupiter show far-UV emissions from the impact sites within a similar to 10 min time scale. Positive detections of H-2 Lyman and Werner band (1230-16 20 Angstrom) and H-Ly alpha emissions are made for impacts K and S, an d marginally for P2. No thermal continuum is observed. The radiated fa r-UV output was >10(21) ergs. The H-2 spectrum is consistent with elec tron collisional excitation if significant CH4 absorption is included. Such emissions could result from plasma processes generated by the im pacts. Non-thermal excitation by the high altitude entry and explosion shocks may also be relevant. Emissions by Al+ (1671 Angstrom) and C ( 1657 Angstrom) of cometary origin are tentatively identified.