SHOEMAKER-LEVY-9 - DISTRIBUTION OF RADIANT ENERGY

Multicolor Galileo observations of several SL9 impacts permit derivati on of size and temperature information for the fireball phase. Integra tion of light-curves yields total fireball radiant energy estimates. E vent QI has an initial color temperature of 24 000 K. Total radiant fi reball energy for G was 8.3 x 10(24) erg. The largest event, L, is est imated to be 10(25) erg. Modelling of total energy radiated during the fallback phase shows a much larger energy release during that period- up to 4x10(26) erg for L. The mass required to provide the equivalent kinetic energy is about 1 x 10(13) g, which is a strong lower limit to initial fragment mass. The fallback energy derived for the R impact i s 1x10(25)erg, with the strongest spectral constraints. Fallback energ ies for H and Q1 are about 4 x 10(25) erg, derived from only two spect ral points. The fallback energies extrapolated from the 2.3 mu m light curves of the G and K impacts are 7x10(25) and 9x10(25) erg, respectiv ely. Uncertainties of the fallback energies are an order of magnitude. Improvements to these estimates and their uncertainties will derive f rom the application of more detailed physical models. (C) 1997 Elsevie r Science Ltd. All rights reserved.