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==> This proposal is an extension of EVDISHOE.CHEMSFSO and EVDISHOE.MOLSPEC
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We propose to extend our successful search for gas-phase H2O and CO2
absorption with the ISO satellite toward star-forming regions of different
mass, luminosity and evolutionary state. The data will allow determination of
the gas-phase abundances of these two key molecules, and estimates of their
excitation temperatures. Combined with solid state data on the same species,
the gas/solid-state ratios can be obtained for the dominant grain mantle
components. These ISO observations will provide a unique data set on a
statistically significant set of objects from which important clues on the
physical processes and chemical evolution during the early stages of star
formation can be obtained.
If time is awarded, we propose to transfer the remaining ~28000 s from our
proposal EVDISHOE.CHEMSFSO to this proposal.