KAO Observations of Fragments R, V, and W into Jupiter, July 21-22, 1994

Hunten, Sprague, Witteborn, Kozlowski and Wooden used the High Efficiency 
Faint Object Infrared Grating Spectrometer (HIFOGS) to observe the impacts
of fragments R, V, and W with the KAO.  Because of the timing of
the impacts, we observed the V site about an hour after the fragment
crash time.  We were on target at the time of the W impact, the final
one in the series.  Both sites were readily detected in the long and
short wavelength channels of HIFOGS.  The obvious things in the spectra 
are methane, ethane and acetylene.  We think that these gases, already 
in the atmosphere, were lighted up by a huge, warm bubble of air heated 
by the dissipation of the energy following the explosion of the cometary 
fragments.  Emissions from  methane increased to about ten times the 
pre-impact value.  The  ethane and acetylene emissions also increased by 
many factors.  During the R event the intensity at short wavelengths  
(methane) faded in about 20 minutes;  at longer wavelengths (ethane and 
acetylene) the spectacular emission lines lasted a couple of hours.  
The more rapid disappearance of the emissions at shorter wavelengths, and 
the general fading, are probably explained by the cooling of the bubble 
as it expands.  We were able to make observations at these wavelengths 
because the KAO flies at 12,500m, above most absorbing molecules in the 
Earth's atmosphere.  Interestingly enough, the cometary fragments seemed 
to be exploding and depositing their energy at almost the same pressure 
level in Jupiter's atmosphere.