Infrared Spectroscopy of the Rosette Nebula: \author{Clark, F. O.} Evidence for Molecular Continuum Emitters; The Lack of UIR Emission in the Low Density Interstellar Medium
Session 56 -- Supernova Remnants Observation
Display presentation, Thursday, 2, 1994, 9:20-6:30

## [56.10] Infrared Spectroscopy of the Rosette Nebula: \author{Clark, F. O.} Evidence for Molecular Continuum Emitters; The Lack of UIR Emission in the Low Density Interstellar Medium

{F.O. Clark, R.F. Shipman, M.P. Egan, R. Assendorp, P.R. Wesselius} \author

We have extracted Infrared (8-22 micron) spectra from the IRAS Low Resolution Spectrometer raw data base of sources in the environs of the Rosette Nebula. We find the following: \\ 1. Sources within the ionized region show no emission shortward of about 14 microns, and a featureless continuum rising steeply to the red. \\ 2. Sources in the low density neutral material show continua slowly rising to the red across the LRS band. \\ 3. Two sources show the 7.7 and 11.3 micron UIR bands in addition to a red continuum. Both are locations of mm-wave CO emission. \\

We interpret the lack of 8-14 micron emission from the sources within the ionized region as due to the destruction of the carriers of this emission by the UV radiation present there. We argue that solids are not destroyed on a sufficiently short time scale, and that the 8-14 micron emission may therefore come from molecular carriers. However, the lack of UIR feature emission indicates that the molecular carriers either differ from those of the UIR bands or are insufficiently excited to emit in the UIR bands. The UIR emission is localized in these data to a few very compact sources, and the UIR emission is not a characteristic of diffuse interstellar material.