The following document lists the file abstract/WREACH_PHASE.abs
from catalogue VI/111.
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We propose to observe the C+ 158-micron line emission in order to trace the phase transitions of C in the translucent cloud G236+39 (spring launch) or the edges of the dark cloud L183 (autumn launch). G236+39 has been shown to contain the phase transitions from H/H2 and C+/CO, and we will propose to observe the CI 609-micron line for comparison to the ISO observations. L183 has already be observed in CI line. Both G236+39 and L183 have been observed in CO and its 13CO isotopomer. The C+ observations will be combined with CI observations in order to distinguish the C+/CI and CI/CO transitions, which must lie between the cloud edge and the CO cores. These phase transitions are a key both to the cloud thermodynamics (governed by the cooling through the C+ line) and the cloud chemistry of C-bearing species (governed by the abundance of C+).