THE CIRCUMSTELLAR ENVIRONMENT OF IRAS-05338-0624

Millimeter continuum and spectral line observations with 10'', 30'', a nd 60'' resolution are used to characterize the structure and chemistr y of the gas around the young, embedded star, IRAS 05338-0624. On arcm inute scales, emission from dense gas tracers outline an isolated cond ensation centered on the IRAS source position. The condensation is cha racterized by a size of similar to 60'', a density of 2 x 10(5) cm(-3) , and a virial mass of 40 M(circle dot) . Interferometric CS J = 2-1 o bservations show two peaks, one toward the continuum peak and the othe r toward a position 14'' west and 8'' south. Single-dish maps of SO, C H3OH, and SiO show pronounced wing emission to the west of the IRAS so urce, which interferometer observations reveal to be a compact region of outflow activity. CS emission at redshifted and blueshifted velocit ies reveals a bipolar outflow oriented with a position angle of 45 deg rees, while SiO emission appears to be tracing a fast shock interactio n region at the CS red-lobe peak, 14'' west and 8'' south of the IRAS source. Finally, (HCO+)-C-13 emission traces clumps of quiescent gas t oward the IRAS source and adjacent to the blue lobe of the outflow. Co lumn densities and molecular fractional abundances are derived to expl ore the interaction between the surrounding condensation and the young stellar object. We fmd evidence for gas phase depletions within the o verall condensation in several gas tracers (GO, CS, HCN, SO) but not i n the region immediately around the young stellar object. Enhanced abu ndances of SO, CH,OH, and SiO (by factors of 4, >100, >1000, respectiv ely) are observed in the shocked gas; these enhancements may be explai ned in terms of a nondissociative shock liberating mantle materials th at contain some amount of refractory materials, a moderate velocity di ssociative shock in which only minor sputtering of Si occurs, or a sho ck that impacts surrounding material with a range of speeds.