Abstract
In our CO J = 1 - 0 maps we identify an "eggplant-shaped", thin bipolar outflow shell which outlines the extended blue lobe of the massive bipolar outflow in the central region of Mon R2. The projected length and width of the shell are about 5.3 pc and 2.7 pc respectively, and the average projected thickness of the shell is 0.3 pc. This remarkably well-defined narrow shell along with the peculiar line profiles strongly favor outflow models with largely uitfilled lobes. A good fit of the shape of the shell by the recent simple outflow model of Shu et al. (1991) seems to suggest that the model may have grasped some essential elements of the real situation, although our consideration of the mass distribution confirms a conclusion of a previous study (Masson & Chernin 1992) that the model predicts too much mass at small polar angles (< 140).
