MOLECULAR OUTFLOWS IN THE YOUNG OPEN CLUSTER IC 348

摘要

We present a wide-field survey of the young open cluster IC 348 for molecular H_2 outflows. Outflow activity is only found at its southwestern limit, where a new subcluster of embedded sources is in an early phase of its formation. If the IC 348 cluster had been built up by such subclusters forming at different times, this could explain the large age-spread that Herbig (1998) found for the IC 348 member stars. In addition to several compact groups of H_2 knots, our survey reveals a large north-south oriented outflow, and we identify the newly discovered far-infrared and millimeter object IC 348 MMS as its source. New deep images in the 1-0 S(1) line of molecular hydrogen trace the HH 211 jet and counterjet as highly collimated chains of knots, resembling the interferometric CO and SiO jets. This jet system appears rotated counterclockwise by about 3° with respect to the prominent H_2 bow shocks. Furthermore, we resolve HH 211-mm as a double pointlike source in the millimeter continuum.