VLA RECOMBINATION LINE OBSERVATIONS OF THE COMETARY H-II-REGION G34.3+0.2 - DYNAMICS AND PHYSICAL-PROPERTIES

We have observed the H93 alpha radio recombination line emission toward the cometary H II region G34.3+0.2 component C. A velocity gradient with a total extent of approximate to 35 km s(-1) is found in the H93 alpha line emission perpendicular to the symmetry axis of the cometary H II region. A smaller velocity gradient is found parallel to the symmetry axis. The moving star bow shock model and the champagne outflow model have been suggested to explain observations of G34.3+0.2C. Neither model adequately matches the available velocity data. G34.3+0.2 components A and B are found near G34.3+0.2C. The continuum spectral indices of components A and B are consistent with that expected for an ionized wind outflow. We suggest a qualitative model for the region where the ionizing star of the cometary H II region G34.3+0.2C photoevaporates material from a hot ultracompact molecular core found just to the east of the continuum emission. Interaction between the ionized gas of the cometary H II region and winds from components A and B may explain many of the current observations. We have also mapped the 6(16) --> 5(23) transition of H2O toward G34.3+0.2. We find strong H2O maser emission within a approximate to 50'' x 30'' region. Some of the H2O masers are projected onto sources of radio continuum emission, but others are found well separated from radio continuum emission.