Molecular gas phase counterparts to solid state grain mantles features: implication for gas/grain chemistry
Boulanger, F.; Puget, J. -L.; Dartois, E.; Habing, H. J.; Jourdain de Muizon, M.; D'Hendecourt, L.; Breitfellner, M.
France, Spain, Netherlands
Abstract
We present ISO SWS (AOT6) observations of the protostellar object RAFGL 7009S. This source is particularly interesting for the characterisation of chemistry arising from grain surfaces and mantles, since the solid state features of many simple molecules such as H_2O, CO, CO_2, (13) CO_2 and CH_4 are detected, together with weaker features not yet unambiguously identified. Gas phase H_2O, CO_2, CH_4 and CO can also be seen superimposed on the much broader solid state features. We derive an estimate for the gas phase temperature around 50K. The gas to solid ratios of these simple molecules is found to be >=0.2 for H_2O, ~ 0.2 for CH_4, and an order of magnitude lower for CO_2. We discuss the possible implications for interstellar chemistry in such objects.