THE MOLECULAR CORES IN THE L1287, AFGL-5142, AND IRAS 20126+4104 REGIONS

The NH3 (J, K) = (1, 1) and (2,2) line emission was mapped toward three regions with molecular outflows, L1287, AFGL 5142, and IRAS 20126+4104, using the Effelsberg 100 m telescope. Additional (CO)-O-18 (J = 2 --> 1) and CS (J = 3 --> 2) observations of L1287 were carried out with the IRAM 30 m telescope. For the three regions, the high-density molecular core, as traced by the ammonia emission, peaks very close to the position of the proposed powering sources of the outflows. In AFGL 5142 we favor the radio continuum source proposed by Torrelles et al. (1992b) as the powering source of the outflow. The molecular cores best resolved by the telescope beam are elongated in a direction perpendicular to the outflow axis. The clearest elongation is seen in the most collimated outflow, that of L1287. For this source, a remarkable velocity gradient can be seen along the major axis of the high-density condensation, consistent with a rotation of the core. For L1287 and AFGL 5142 we find that the masses of the high-density cores are much higher than the masses of the outflows, indicating that the elongation of the cores cannot be a consequence of the interaction with the molecular outflow and that the cores can play an important role in the large-scale collimation of the bipolar molecular outflows. For all the cores the molecular gas is probably heated by an internal source. In particular, in L1287 we find a local heating of the molecular gas and line broadening toward the position of the ammonia peak, indicating a physical association of the high-density gas with the powering source of the outflow.