Understanding how and when outflows ``turn on'', how long the outflow phase lasts, and the outflow driving mechanism, are critical to understanding the entire star formation process. We are pursuing an ongoing project to relate the evolutionary stages of IRAS sources in the Mon OB1 dark cloud to the morphology and energetics of outflows associated with some of these sources in order to test current models of the outflow driving mechanism and investigate the onset and length of the outflow phase of early stellar evolution. We are refining prior evolutionary classifications (Margulis, Lada, & Young 1989, ApJ, 345, 906) of IRAS sources in Mon OB1 through HiRes processing of IRAS data, and submillimeter continuum mapping of these sources. We present new, fully-sampled, CO J=2->1 and J=1->0 maps of outflows in this cloud, which were obtained using the on-the-fly mapping technique at the NRAO 12 m telescope(1) on Kitt Peak. These observations yield detailed information on outflow structure, kinematics, and excitation conditions, and allow for more accurate estimates of outflow parameters than the original survey of outflows in this cloud (Margulis, Lada, & Snell 1988, ApJ, 333, 316). Low-intensity, very high velocity, gas at T_R(*<100) mK suggests bipolarity in two sources previously reported to be monopolar. G. A. W.-C. was supported by a National Research Council Fellowship for part of this work, and is currently supported by a U. C. President's Fellowship and NASA grant NASA/GRO NAG5-3349. (1) The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.
American Astronomical Society Meeting Abstracts
- Pub Date:
- December 1996