Ultracompact HII regions are the earliest manifestations of O stars as they approach the main sequence. As such, they are key signposts of massive star formation. The VLA has led the way in studies of the number and nature of these objects. However, a significant remaining mystery, the "lifetime problem", hints at how little we really understand. The number of UCHII regions greatly exceeds the number we would expect based on their dynamical lifetimes and the OB star formation rate. An understanding of this paradox and of the physics underlying it has been hampered by our inability to study the detailed kinematics of the regions.
The University of Texas mid-IR spectrograph, TEXES, operates in the 5-20 micron region with a resolution of 3 km/s. We have observed the detailed kinematics of UCHII regions with TEXES by mapping the 12.8 micron line of NeII. These maps provide a unique window into the internal velocity structure of the regions. We will discuss the UCHII region results and highlights of other new and exciting results from high-resolution spectroscopy in the mid-IR.
Friday, 08 Nov 2002
11:00am
Array Operations Center Auditorium
Local Host: Claire Chandler