The following document lists the file abstract/DOSIP_PROP_COM.abs
from catalogue VI/111.
A plain copy of the file
(without headers/trailers) may be downloaded.
The study of comets is of great importance to our understanding of the solar system and its origin. Comets comprise the most primitive material in the solar system and observations of their composition are diagnostic of the environment in which they formed. In recent taxonomic classification of comets, we have clearly separated out the majority ( 70%) of comets having "typical" molecular abundances from a second distinct class of comets that exhibit significant depletions in the carbon-chain species (C2 and C3). The ISO Guaranteed Time targets; P/Kopff, P/Churyumov-Gerasimenko, and P/Wild 2 are all members of the "typical" class of comets. The "carbon-chain depleted" class of comets must be studied in similar detail as those of the "typical" class if we are indeed to gain a firm understanding of the processes that took place during the early solar system. Two of the three most extreme members of the the "carbon-chain depleted" class are positioned favorably for observations by ISO. With an autumn launch, comet P/IRAS would be the target. For a spring launch, the target would be P/Wolf-Harrington, the most extreme member of this class, with P/IRAS serving as a secondary target. These targets have gas and dust production levels approximately a factor of 3-5 below that of the principal GTO target, P/Kopff and about 1% the production of P/Halley. Results from this observational programme are highly complementary to the Guaranteed Time Observations of comets [PI, E.Gruen].