HUBBLE-SPACE-TELESCOPE OBSERVATIONS OF COMET-P SHOEMAKER-LEVY-9 (1993E)/

The Hubble Space Telescope observed the fragmented comet P/Shoemaker-L evy 9 (1993e) (P indicates that it is a periodic comet) on 1 July 1993 . Approximately 20 individual nuclei and their comae were observed in images taken with the Planetary Camera. After subtraction of the comae light, the 11 brightest nuclei have magnitudes between approximately 23.7 and 24.8. Assuming that the geometric albedo is 0.04, these magni tudes imply that the nuclear diameters are in the range approximately 2.5 to 4.3 kilometers. If the density of each nucleus is 1 gram per cu bic centimeter, the total energy deposited by the impact of these 11 n uclei into Jupiter's atmosphere next July will be approximately 4 x 10 (30) ergs (approximately 10(8) megatons of TNT). This latter number sh ould be regarded as an upper limit because the nuclear magnitudes prob ably contain a small residual coma contribution. The Faint Object Spec trograph was used to search for fluorescence from OH, which is usually an excellent indicator of cometary activity. No OH emission was detec ted, and this can be translated into an upper limit on the water produ ction rate of approximately 2 x 10(27) molecules per second.