Modelling of IR emission of interstellar clouds. I - Emission of isolated clouds and dust abundance variations
J. P. Bernard, F. Boulanger, F. X. Desert, J. L. Puget;
AaA, 1992, 263, 258
ABSTRACT:A model for the IR emission and extinction properties of small dust particles is used here to compute the IR emissions in the IRAS photometric bands
for a set of isolated, spherical, and nonhomogeneous clouds heated by the
local interstellar radiation field.
It is predicted that the IR limb
brightening (LB) in the IRAS photometric bands caused by selective absorption of UV
photons of different energies in the cloud generally happens for central
extinctions over 4 mag at 12 microns and greater than 10 mag at 100 microns and
intermediate extinctions for the other IRAS bands.
The surface brightness in the
four IRAS bands is limited to about 0.4, 0.6, 3, and 10 MJy/sr at 12, 25, 60, and
100 microns respectively when no strong density discontinuity is present
at the cloud edge.
KEYWORDS: abundance, cosmic dust, infrared radiation, interstellar matter, molecular clouds, astronomical models, brightness distribution, infrared astronomy satellite, radiative transfer
PERSOKEY:dust, mir, fir, ,
CODE: bernard92