Methane and carbon monoxide infrared emissions observed at the Canada-France-Hawaii Telescope during the collision of comet SL-9 with Jupiter

Observations with the Fourier Transform Spectrometer were conducted in spectral ranges from 1.6 to 4.7 µm from July 17 to 21 (UT) on the hot plumes appearing on the limb as well as hours or days after the impacts. We present here an analysis of the methane emission observed at 3.3 µm some 10 min after the C impact, indicating the presence of a very small (less than 100 km wide) hot region with temperatures in the 750–1500 K range within the 0.1- to 0.01-mbar region. We also report the detection of CO emission at 4.7 µm 4.5 hrs after the L impact, indicative of a temperature of 274±10 K at the ∼1016 CO molec cm−2 level. The observations suggest that the stratospheric temperature decreases wi…