Multiple Jets from the High‐Mass (Proto)stellar Cluster AFGL 5142

Abstract

We present studies of a massive protocluster AFGL5142 in the J=2-1 transition of the CO isotopologues, SO, CH 3 OH and CH 3 CN lines, as well as continuum at 225 GHz and 8.4 GHz. The 225 GHz continuum emission reveals three prominent peaks MM-1, MM-2 and MM-3 with estimated circumstellar material of 3, 3, and 2 M ⊙ , respectively. MM-1 and MM-2 are associated with strong CH 3 CN emission with temperatures of 90 ± 20 and 250 ± 40 K, respectively, while both MM-1 and MM-3 are associated with faint continuum emission at 8.4 GHz. The heating implied by the temperature indicates that MM-1 and MM-2 cores contain embedded massive young stars. Additional dust continuum peaks MM-4 and MM-5 appear to be associated with H 2 O masers. With many continuum sources at cm and mm wavelengths, and those already identified in the infrared, this region is forming a cluster of stars.A total of 22 lines from 9 molecules are detected. The line strength varies remarkably in the region. The strong SO emission is found both in molecular outflows and cloud cores. CH 3 OH emission, on the contrary, is much weaker in molecular outflows, and is detected toward hot cores MM-1 and MM-2 only, but is absent in less massive and perhaps less evolved cores MM-3, MM-4 and MM-5. The modeling of the CH 3 CN spectra yields an abundance relative to H 2 of 1 × 10 −8 and 4 × 10 −8 for the MM-1 and MM-2 cores, respectively. With similar core mass, the higher temperature and CH 3 CN abundance in the MM-2 core suggest that it might be at a more evolved stage than the MM-1 core.

Infall and outflow within 400 AU from a high-mass protostar

“…Our higher angular resolution measurements allow us to identify MM-1 unambiguously as the driving source of the NW-SE oriented outflow, traced by H 2 O masers and radio continuum at radii <400AU and by CO emission at radii >2000 AU. Zhang et al (2007) derived a momentum rate of 2 × 10 −3 M yr −1 km s −1 , which agrees well with the momentum rate of the H 2 O maser outflow. We conclude that the ionized jet observed in the radio continuum emission and the molecular outflow probed by water masers can account for the acceleration of the large-scale CO outflow driven by MM-1.…”

“…(Goddi & Moscadelli 2006) and 8.4 GHz (Zhang et al 2007). Published maps used natural weighting of the uv-data and had an angular resolution ∼0.…”

“…H 2 O masers are concentrated in two clusters that are associated with the two components of the 8.4 GHz continuum: the one toward the SE has blue-shifted l.o.s. velocities with respect to the systemic velocity of the region (-1.1 km s −1 ; Zhang et al 2007); the other one located to the NW has redshifted l.o.s. velocities.…”

“…On larger scales, CO (2-1) line emission revealed a multiple system of outflows, that are oriented north-south, northeastsouthwest, and NW-SE (Zhang et al 2007). The poor angular resolution of the SMA (1-3 ) precluded a clear identification of the driving sources of outflows.…”

“…Observations with the Submillimeter Array (SMA) at 1.3 mm identified a high-mass protocluster containing five dusty mm cores and three CO outflows within a few arcseconds of each other (Zhang et al 2007). The focus of this Letter is the mm core MM-1, which shows hot-core chemistry, exhibits radio continuum emission from ionized gas, and powers water and methanol masers , hinting that it is likely the most massive object in the cluster.…”