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Session 21 - Massive Star Formation & Ultracompact HII Regions.
Oral session, Monday, January 13
Harbour B,

[21.05] H II Regions and Photodissociation Regions in NGC 6334

J. M. Jackson, K. E. Kraemer (Boston U.)

We present new VLA 3 cm continuum images of the southern portion of the H II region/molecular cloud complex NGC 6334. The radio continuum source G351.20+0.70, first discovered by Moran et al. (1990), is resolved into a 1 pc (2') diameter shell. In addition, we have discovered an unresolved radio counterpart to the near IR source NGC 6334 A-IRS 20, as well as three unresolved radio sources coincident with the FIR source NGC 6334 V.

The G351.20+0.70 radio shell is surrounded by [C II] 158 um emission, which in turn is surrounded by CO emission. Apparently, it is a classical photodissociation region, although the ionizing source or sources remain unidentified. A B0 ZAMS star is required to account for the observed radio flux.

The unresolved radio sources associated with IRS 20 and NGC 6334 V are consistent with Stromgren spheres surrounding B2 ZAMS stars in a region of fairly high electron density (n \sim 50,000 cm^-3). The inferred stellar luminosity, however, cannot account for the observed infrared luminosity. A cluster of lower mass stars may account for this discrepancy. Alternatively, the stars may be in a protostellar phase and derive most of their luminosity from accretion.

Program listing for Monday