Parent volatiles in comet 9P/Tempel 1: Before and after impact

We quantified eight parent votatiles (H(2)O, C(2)H(6), HCN, CO, CH(3)OH, H(2)CO, C(2)H(2), and CH(4)) in the Jupiter-family comet Tempel 1 using high-dispersion infrared spectroscopy in the wavelength range 2.8 to 5.0 micrometers. The abundance ratio for ethane was significantly higher after impact, whereas those for methanol and hydrogen cyanide were unchanged. The abundance ratios in the ejecta are similar to those for most Oort cloud comets, but methanol and acetylene are tower in Tempel 1 by a factor of about 2. These results suggest that the volatile ices in Tempel 1 and in most Oort cloud comets originated in a common region of the protoplanetary disk.