2007A&A...470..269Z -
Astronomy and Astrophysics, volume 470, 269-279 (2007/7-4)
A jet-like outflow toward the high-mass (proto) stellar object IRAS 18566+0408.
ZHANG Q., SRIDHARAN T.K., HUNTER T.R., CHEN Y., BEUTHER H. and WYROWSKI F.
Abstract (from CDS):
Studies of high-mass protostellar objects reveal important information regarding the formation process of massive stars. We study the physical conditions in the dense core and molecular outflow associated with the high-mass protostellar candidate IRAS 18566+0408 at high angular resolution. We performed interferometric observations in the NH3(J,K)=(1,1), (2,2) and (3,3) inversion transitions, the SiO J=2-1 and HCN J=1-0 lines, and the 43 and 87GHz continuum emission using the VLA and OVRO. The 87GHz continuum emission reveals two continuum peaks MM-1 and MM-2 along a molecular ridge. The dominant peak MM-1 coincides with a compact emission feature at 43GHz, and arises mostly from the dust emission. For dust emissivity index β of 1.3, the masses in the dust peaks amount to 70M☉ for MM-1, and 27M☉ for MM-2. Assuming internal heating, the central luminosities of MM-1 and MM-2 are 6x104 and 8x103L☉, respectively. The SiO emission reveals a well collimated outflow emanating from MM-1. The jet-like outflow is also detected in NH3at velocities similar to the SiO emission. The outflow, with a mass of 27M☉, causes significant heating in the gas to temperatures of 70K, much higher than the temperature of ≲15K in the extended core. Compact (<3'') and narrow line (<1.5km/s) NH3(3,3) emission features are found associated with the outflow. They likely arise from weak population inversion in NH3similar to the maser emission. Toward MM-1, there is a compact NH3structure with a linewidth that increases from 5.5km/s FWHM measured at 3'' resolution to 8.7km/s measured at 1'' resolution. This linewidth is much larger than the FWHM of <2km/s in the entire core, and does not appear to originate from the outflow. This large linewidth may arise from rotation/infall, or relative motions of unresolved protostellar cores.
Abstract Copyright:
∼
Journal keyword(s):
ISM: kinematics and dynamics - ISM: H II regions - ISM: clouds - masers - ISM: jets and outflows - stars: formation
Nomenclature:
Fig.1, text: [ZSH2007] MM-N (Nos 1 to 2).
Simbad objects:
13
Full paper
View the references in ADS
To bookmark this query, right click on this link: simbad:2007A&A...470..269Z and select 'bookmark this link' or equivalent in the popup menu