Constraining the Dust Opacity Law in Three Small and Isolated Molecular
  Clouds
  Density profiles of isolated cores derived from thermal dust continuum
emission rely on models of dust properties, such as mass opacity, which are
poorly constrained. With complementary measures from near-infrared extinction
maps, we can assess the reliability of commonly-used dust models. In this work,
we compare Herschel-derived maps of the optical depth with equivalent maps
derived from CFHT WIRCAM near-infrared observations for three isolated cores:
CB68, L429, and L1552. We assess the dust opacities provided from four models:
OH1a, OH5a, Orm1, and Orm4. Although the consistency of the models differs
between the three sources, the results suggest that the optical properties of
dust in the envelopes of the cores are best described by either silicate and
bare graphite grains (e.g., Orm1) or carbonaceous grains with some coagulation
and either thin or no ice mantles (e.g., OH5a). None of the models, however,
individually produced the most consistent optical depth maps for every source.
The results suggest that either the dust in the cores is not well described by
any one dust property model, the application of the dust models cannot be
extended beyond the very center of the cores, or more complex SED fitting
functions are necessary.
