Scattering in the 3-μm interstellar ice band

CVF spectra of the 3μm ice band obtained at several locations in the KL infrared reflection nebular are presented. A short wavelength extension in these features is explained by a single scattering model in which the wavelength dependence of the grain scattering cross-section is overlapped by an extinction spectrum. The author obtains best fits with larger-than-Rayleigh particles (5.-.7 μm). With one exception, one ammonia-water ice mixture gives good agreement with all the spectra. CVF spectra of the 3 μm feature in the protostars, CRL 2591 and NGC 2264 IR, also exhibit short wavelength extensions. He explains this wing with a model in which the intrinsic absorption spectrum of the protostar is mixed with that of a surrounding reflection nebula