The following document lists the file abstract/FCLARK_KLEINROK.abs
from catalogue VI/111.
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Small interstellar dust grains radiate from wavelengths of a few microns to beyond 25 microns. We have previously studied the effects of progressively decreasing radiation fields on dust in interstellar clouds. This study extends that work into high radiation field environments. Our IRAS survey and LRS data from neutral high radiation environments show broad band featureless emission across the IRAS LRS spectrometer passband. 12 and 25 micron survey emission simultaneously decline as radiation density increases, suggesting destruction of carriers in both bands. Deep inside high radiation environments, IRAS survey and spectral data may show graybody emission. Our data and models raise fundamental questions about dust in high radiation field regimes. The data suggest that small dust grains may not emit by the same process as radiation density increases. These data suggest destruction of the carriers correlated with radiation density, but not with radiation hardness. Ionizing radiation may dissociate molecular but not solid state carriers. Reduction of progressively larger carriers with increasing radiation density is predicted by solid state runaway sublimation. Neither fit the data well. In very high radiation density environments IRAS LRS spectra show emission beginning at 14 microns peaking near 20 microns which may be gray body emission. Data at longer wavelengths resolve the issue. Solid state or molecular, non-thermal continuum emission, grey-body emission, and spectral structure, these fundamental issues on the nature of small dust grains may be uniquely answered with ISO. Each appears spatially restricted. Our present data and models reveal locations to address points.