filamentary dark clouds (fdc), or globular filaments (gf), are nearby (100 - 400pc distance) molecular clouds containing small numbers of dense cloud cores connected by low density gas and dust. these clouds look like strings (the low opacity material) with beads (the dense cores) strung along their lengths, often in a periodic fashion. these fdcs may represent swept-up material, created by blast waves or strong stellar winds, or they may be a stable form of galactic molecular clouds. they most likely represent a transient phase of the molecular material, on its way from having resided in a larger cloud complex to in the future becoming a collection of bok globules, or dispersing altogether. we seek to determine the physical nature of the dust contained in the denser cores (beads) and filamentary material (string) for a sample of fdcs. the physical parameters to be probed under this program include the dust temperatures, dust densities, and dust compositions. iras was barely able to detect the cold dust in these clouds, and generally only in its longest wavelength channel. however, the longer wavelengths, sensitivity, and pointing capabilities of iso make it the only observatory capable of performing this investigation. we seek to obtain two modest sized (9-10 arcmin) maps in each of five clouds (one map toward a dense core region, one toward a filamentary region, for each cloud) using the isophot c100 and c200 arrays and four filters. these maps will be used to create dust temperature, density, and composition maps, for comparison between the core and filament regions, and to similar resolution maps of the molecular gas obtained at mm wavelengths. these maps will be analyzed to examine the detailed temperature structure within the cores in order to model their thermal balance and to probe for variations in the interstellar radiation field, the chief source of input energy for these cold clouds.
Instrument
PHT32
Temporal Coverage
1996-10-20T19:11:18Z/1996-10-20T21:34:48Z
Version
1.0
Mission Description
The Infrared Space Observatory (ISO) was the worlds first true orbiting infrared observatory. Equipped with four highly-sophisticated and versatile scientific instruments, it was launched by Ariane in November 1995 and provided astronomers world-wide with a facility of unprecedented sensitivity and capabilities for a detailed exploration of the Universe at infrared wavelengths.
European Space Agency, Dan P. Clemens, 1998, 'DUST TEMPERATURES AND DENSITIES IN FILAMENTARY DARK CLOUDS COLD DUST MAPS OF GLOBULAR FILAMENT CLOUDS', 1.0, European Space Agency, https://doi.org/10.5270/esa-h50zur5
