Detection of the ``44 MU m'' band of water ice in absorption in combined ISO SWS-LWS spectra
Heras, A. M.; Tielens, A. G. G. M.; Cox, P.; Dartois, E.; Roelfsema, P. R.; Lim, T.; Schmitt, B.; Jones, A. P.; Swinyard, B.; Jourdain de Muizon, M.; D'Hendecourt, L.
France, Netherlands, Spain, United Kingdom
Abstract
We report the detection of the transverse optical vibrational band of water ice at 44 microns in absorption towards two embedded infrared sources, IRAS 18316-0602 (RAFGL7009S) and IRAS 19110+1045. The water band extending from 30 to about 80 microns is a prominent feature in the combined ISO SWS and LWS grating spectra. Using new optical constants for amorphous and crystalline water ice, we have modeled the infrared spectra of the two embedded sources with a radiative transfer code. Most of the observed absorption bands are well fit by H_2O, CO, and CO_2 ice mantles on silicate and graphite cores. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) and with the participation of ISAS and NASA