SPECTROSCOPY OF MOLECULAR CLOUD SOURCES AT 6-7 MICRONS.

Spectroscopy was obtained for several infrared sources embedded in molecular clouds. The spectrometer used a cooled grating and was flown on the Kuiper Airborne Observatory. Spectra were obtained for portions of the features at 6.0 and 6.8 microns, which are seen in absorption against infrared sources lying deep in molecular clouds. The present observations were obtained with a resolution of 0.008 micron, and confirm the continuous nature of the absorption, thus supporting a dust-grain origin. A search for residual structure in the absorption features on a scale of 0.01 to 0.10 micron revealed none in the 6.0 micron feature. Structure on a scale of 0.05 micron may be present in the 6.8 micron feature. Suggested identifications of the materials responsible for these features are discussed.