The Dust Properties of Bubble HII Regions as seen by Herschel
  Because of their relatively simple morphology, "bubble" HII regions have been
instrumental to our understanding of star formation triggered by HII regions.
With the far-infrared (FIR) spectral coverage of the Herschel satellite, we can
access the wavelengths where these regions emit the majority of their energy
through their dust emission. At Herschel wavelengths 70 micron to 500 micron,
the emission associated with HII regions is dominated by the cool dust in their
photodissociation regions (PDRs). We find average dust temperatures of 26K
along the PDRs, with little variation between the HII regions in the sample,
while local filaments and infrared dark clouds average 19K and 15K
respectively. Higher temperatures lead to higher values of the Jeans mass,
which may affect future star formation. The mass of the material in the PDR,
collected through the expansion of the HII region, is between ~300 and ~10,000
Solar masses for the HII regions studied here. These masses are in rough
agreement with the expected masses swept up during the expansion of the \hii\
regions. Approximately 20% of the total FIR emission is from the direction of
the bubble central regions. This suggests that we are detecting emission from
the "near-side" and "far-side" PDRs along the line of sight and that bubbles
are three-dimensional structures. We find only weak support for a relationship
between dust temperature and beta, of a form similar to that caused by noise
and calibration uncertainties alone.
