We intend to examine the massive star formation region NGC 6334 in the near-
and mid-infrared in order to investigate the dust properties at each
of 8 sites of massive star formation in the cloud: NGC 6334 A, C, D, E, F,
V, I(N) and G351.20+0.70.
By making SWS full-grating scans toward each site of massive star formation and
examining the fine-structure lines from ionic species, we will determine the
hardnesses of the UV fields, and thus derive the ZAMS spectral types. To
determine the gas density and UV field strength based on PDR models, we will
use the [Si II] 35um line, along with the [C II] 158um and [O I] 145um
lines from our previously observed ISO LWS full-grating scans. Because the
[O I] 63um is anomalously faint toward at least two of the sources in NGC
6334, probably due to self-absorption, the optically thin [S II] 35um line
is essential for testing the model predictions. We will investigate the
dependence on the hardness of the UV field of the UIR features at 6.3, 7.7,
8.6 and 11.3um. We will also examine the relative strength of ice vs.
silicate features and their dependence on the hardness of the UV field.
We will also image each site with ISOCAM through 4 settings of the CVF filter.
Because the sources are so bright, we need the CVF filter to avoid saturation.
By imaging the well-isolated 6.3um UIR feature at each site, we will determine
the survivability of small grains in hard/intense UV fields. In order to
separate the UIR feature from the continuum emission, we will take images
at 5.8 and 6.8um. These continuum images, plus the fourth CVF filter setting
at 14.8um, will allow us to determine the dust opacity, a crucial input
parameter for PDR models.