Program: GN-2005B-Q-83

Low resolution, R=40, spectra of many embedded sources show an inflection at 11.2 um in addition to the usual broad 9.7 micron amorphous silicate band. Recent high resolution, R=150, spectra of a few sources obtained by us resolve the inflection into a bona fide absorption feature. However, there has been no statistical study of the 11.2 micron band to aid in its identification. This proposal aims to perform such a study. In so doing we will obtain a more precise determination of the feature's spectral profile for comparison to candidate carriers, e.g. crystalline silicate. Comparison of the 11.2 micron optical depth to that at 9.7 microns will determine if a relation exists between the two bands, again aiding in identifcation.