The following document lists the file abstract/ASCHULTZ_HHSHOCKS.abs
from catalogue VI/111.
A plain copy of the file
(without headers/trailers) may be downloaded.
Herbig-Haro objects are emission nebulae formed when outflow from a YSO impacts on ambient matter, setting up shocks in both the outflowing and ambient material. The exact nature of these shocks is still poorly understood, particularly the relationship between the shocked atomic and molecular gas. One of the chief problems is that the shocked atomic and molecular gas seem to be coincident, despite the fact that the shocks which excite the atomic gas should dissociate the molecules. Although several explanations have been proposed, the question remains unresolved. An important clue in the resolution of the puzzle lies in the observations of shocked molecular hydrogen. Observations of hydrogen lines arising from widely varying upper energy states can map the temperature structure of the cooling shock, and therefore identify the type of shock. Unfortunately, the molecular hydrogen lines readily available from the ground are either very faint, or else span a very narrow range of upper energy states. If we are to understand these shocks through the molecular hydrogen emission we must have observations from a greater range of lines. The most important of these "missing" lines lie in the ISO wavelength range. We propose to use the CAM to image some of these lines. The ISO observations will be compared to ground-based 2um images in order to map the temperature structure and extent of the shocked gas.