EPoS Contribution
EPoS Contribution
Outflow detection in a 70 micron dark high-mass core

Siyi Feng
MPE, Garching bei München, DE
We observed a high-mass (> 40 Msol), low luminosity (<10 Lsol) 70 μm dark molecular core G28.34 S-A, using IRAM 30 m telescope, the NOEMA, and the SMA interferometer. We detected the spatially resolved SiO (2-1) line emission in this source at a linear resolution of ~0.1 pc, while both the 1.3 mm and 3.4 mm continuum image seem smooth and do not spatially resolve any sub-structures. The SiO emission exhibits two lobes which are West-East oriented and centred on the continuum. These lobes correspond to red-shifted and blue-shifted gas with velocities up to 40 km/s relative to the quiescent cloud. This indicates the presence of a strong bipolar outflow from this 70 μm dark core. Our SiO detection is consistent with ALMA archival data of SiO (5-4), whose high-velocity blue-shifted gas reveals a more compact lobe spatially closer to the dust center. We find that this outflow has a high momentum (~3 Msol km/s), high mechanical luminosity (~30.5 Lsol), and high mass entrainment rate (~10-5) Msol /yr), which infers that the central source may be in a transient evolutionary stage between the prestellar and the protostellar object. We also find that the low-velocity components (of Vlsr -5~Vlsr+3 km/s) have an extended, NW-SE oriented distribution. Our results indicate that star-forming activities have already begun in the 70 μm dark molecular core, and they also strongly suggest that molecular lines are advantageous over the traditional "infrared color" classification, in physically characterising the earliest evolutionary stages of high-mass star-forming regions.
H. Beuther, MPIA, DE
Q. Zhang, CfA, US
Z. Zhang, ESO, DE
K. Wang, ESO, DE
H. B, Liu, ESO, DE
K. Qiu, Nanjing U, CN
Suggested Session: Massive Star Formation