Ground- and Space-Based Mid-Infrared Observations of S140: ISO Spectroscopy and MIRAC Spectral Imaging
Abstract
We have imaged the S140 H II region with the MIRAC2 CVF at wavelengths from 9.7 to 13.2 mu m, as well as with broadband filters at 12.5 and 20.6 mu m. With the broadband filters, we have discovered a previously undetected mid-infrared source just north of S140 IRS 2, and have detected a mid-infrared counterpart for the radio source S140 VLA 4. The three brightest mid-IR sources have 9.7 mu m silicate absorption, but the absorption depth varies from source to source. The shape of the rising, long-wavelength side of the absorption feature is also non-uniform. This non-uniformity in the spectral shape may be due to emission from the 11.2 mu m UIR feature that is not present toward all the sources. We examine the region for emission from the 12.8 mu m [Ne II] transition. We also compare the ISO-SWS spectrum toward S140 with our ground-based results. The SWS spectrum shows a rich spectrum of ice absorption features, including H_2O and CO_2 absorption, but no CO absorption features. We contrast the S140 SWS spectrum to that of NGC 6334 V, which has the same ZAMS spectral type as S140 but has a very different mid-infrared spectrum. We suggest that the differences may be attributed to different evolutionary states of the two sources.
- Publication:
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American Astronomical Society Meeting Abstracts #194
- Pub Date:
- May 1999
- Bibcode:
- 1999AAS...194.6804K