Molecular outflows in the L1641 region of Orion

Little is known about the interaction between molecular outflows associated with young stellar objects and the parent molecular cloud that produced them. This is because (a) molecular outflows are a recently discovered phenomenon and, so, have not had their global properties studied in great detail and (b) molecular clouds have not been mapped to sufficiently high spatial resolution to resolve the interaction. This work addresses the interaction between molecular outflows and the L1641 molecular cloud by both identifying and mapping all the molecular outflows as well as the detailed structure of the cloud. Candidate molecular outflows were found from single point $\sp{12}$CO observations of young stellar objects identified from the IRAS survey data. The candidate sources were then mapped to confirm their molecular outflow nature. From these maps, molecular outflow characteristics such as their morphology, orientation, and energetics were determined. In addition, the Orion molecular cloud was mapped to compare directly with the molecular outflows. The molecular outflows identified were found to have rising infrared spectra, radio continuum emission that suggests a stellar wind or optically thick H sc II region, and molecular line strengths that indicate that they are embedded within a very dense environment. The lack of an optical counterpart for many molecular outflows suggests that they occur at the earliest stages of stellar evolution. The orientations of the molecular outflows appear to lie in no preferred direction and they have shapes that indicate that the molecular cloud is responsible for determining their direction and collimation. The energetics derived for the molecular outflows indicate that there is sufficient momentum available to the molecular cloud from the currently present molecular outflows to support the cloud against gravitational collapse. Remnant holes and adjacent multicomponent lines at some locations in the cloud suggest that past molecular outflows may have disrupted the cloud and are evacuating the region around the source