
We present new 4.5-5.1 micron (2210-1970 cm-1) spectra of embedded protostars, W33 A, AFGL 961 E, AFGL 2136, NGC 7538 IRS 9, and Mon R2 IRS 2, which contain a broad absorption feature located near 4.62 micron (2165 cm-1), commonly referred to in the literature as the "X-C triple bond N" band. The observed peak positions and widths of the interstellar band agree to within 2.5 cm-1 and 5 cm-1, respectively. The strengths of the interstellar 4.62 micrometers band and the ice absorption features in these spectra are not correlated, which suggests a diversity of environmental conditions for the ices we are observing. We explore several possible carriers of the interstellar band and review possible production pathways through far-ultraviolet photolysis (FUV), ion bombardment of interstellar ice analog mixtures, and acid-base reactions. Good fits to the interstellar spectra are obtained with an organic residue produced through ion bombardment of nitrogen-containing ices or with the OCN- ion produced either through acid-base reactions or FUV photolysis of NH3-containing ices.
Cosmic Dust, Extraterrestrial Environment, Spectrophotometry, Infrared, Nitrogen, Ultraviolet Rays, Astronomy, ASTROPHYSICAL ICE ANALOGS, ISM : clouds, INFRARED-SPECTROSCOPY, ISM : molecules, line : identification, stars : pre-main-sequence, Ammonia, TAURUS DARK CLOUD, Nitriles, SPECTRA, Cyanates, ABSORPTION FEATURES, Photolysis, Spectrum Analysis, Astronomical Phenomena, Ice, GRAIN MANTLES, Silanes, XCN BAND, Hydrocarbons, infrared : ISM : lines and bands, MOLECULAR CLOUDS, SOLID CO, MAIN-SEQUENCE STARS, Thiocyanates
Cosmic Dust, Extraterrestrial Environment, Spectrophotometry, Infrared, Nitrogen, Ultraviolet Rays, Astronomy, ASTROPHYSICAL ICE ANALOGS, ISM : clouds, INFRARED-SPECTROSCOPY, ISM : molecules, line : identification, stars : pre-main-sequence, Ammonia, TAURUS DARK CLOUD, Nitriles, SPECTRA, Cyanates, ABSORPTION FEATURES, Photolysis, Spectrum Analysis, Astronomical Phenomena, Ice, GRAIN MANTLES, Silanes, XCN BAND, Hydrocarbons, infrared : ISM : lines and bands, MOLECULAR CLOUDS, SOLID CO, MAIN-SEQUENCE STARS, Thiocyanates
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