To investigate their dust properties, we have imaged three sites of massive
star formation in the giant H II region/star-forming cloud NGC 6334 with t
he MIRAC2 instrument. We obtained high-resolution (1 ") continuum images at
12.5 and 20.6 mu m toward each region, which were compared with observatio
ns of the radio and near-infrared (near-IR) continuum emission. Both compac
t sources and extended emission were found at all three star-forming sites.
The detected sources span a wide range of evolutionary states in this high
ly complex star-forming cloud. The infrared sources near NGC 6334 I were re
solved into at least four subsources. One such source is substantially cold
er, denser, and more optically thick than the other mid-IR sources in the r
egion and may be at the earliest stages of stellar formation. Another may b
e a torus or disk of dust and gas surrounding an embedded B star. NGC 6334
I was also imaged at additional wavelengths (8.8, 9.8, and 11.7 mu m) to se
arch for silicate absorption. Only at the H II region is there a deep silic
ate absorption feature from foreground dust. Toward the NGC 6334 IV, warm d
ust is associated with both the inner portions of the massive molecular tor
us or disk and with the bipolar continuum lobes. A compact mid-IR source, a
ssociated with the near-IR and radio source [HHS87] IRS 20, is cooler and m
ore optically thick than the dust emission associated with the H II region.
Toward NGC 6334 V, four embedded sources were found, including one previou
sly unidentified object. This newly identified compact object, associated w
ith a dust temperature peak and a radio source, is probably in a more advan
ced stage of star formation than the other compact mid-IR sources in NCC 63
34.