PALOMAR OBSERVATIONS OF THE R IMPACT OF COMET SHOEMAKER-LEVY-9 .2. SPECTRA

We present mid-infrared spectroscopic observations from Palomar observ atory of the impact of fragment R of comet P/Shoemaker-Levy 9 with Jup iter on 21 July 1994. Low-resolution 8-13 mum spectra taken near the p eak of the lightcurve show a broad emission feature that resembles the silicate feature commonly seen in comets and the interstellar medium. We use this feature to estimate the dust content of the impact plume. The overall infrared spectral energy distribution at the time of peak brightness is consistent with emission from an optically-thin layer o f small particles at approximate to 600 K. Integrating over the spectr um and the lightcurve, we obtain a total radiated energy from the R im pact of greater than or equal to 2x10(25) ergs and a plume mass of gre ater than or equal to 3x10(13) g.