Discovery of Outflows from Young Stellar Objects in BOK Globules

Results of a search for outflows associated with low-mass young stellar objects (YSOs) in a sample of 41 small Bok globules are presented. New outflows were found in 14 of the samples. Five globules were observed to be rotating, with velocity gradients in the range 0.1-0.7 km/s arcmin. The presence of an outflow was found to be correlated with the value of the IRAS-based spectral index (between 12 and 25 microns) of the YSOs. Outflows were not detected in most globules whose IRAS point sources had spectral indices consistent with T Tauri or older stars. It is inferred that outflows occur during a fairly early stage of the star formation process when the YSOs are still deeply embedded in gas and dust. It is argued that the good mechanical coupling observed to exist between the outflow and the ambient cloud supports the idea that outflows can be responsible for a variety of effects, including cloud support, dispersal, or the end of accretion onto the forming star.