Protostars and Planets VI, Heidelberg, July 15-20, 2013

Poster 1B080

Probing the Complexity of the Infall Envelope around the W3(OH) Massive Star-Forming Region

Kuo, Wei-Ting ( Department of Physics and Institute of Astronomy, National Tsing Hua University)
Chen, Vivien ( Department of Physics and Institute of Astronomy, National Tsing Hua University)

Abstract:
We have observed emissions of HCO (1-0), C18O (1-0), and N2H+ (1-0) toward the W3(OH) massive star-forming region, which is in the course of developing a small OB stellar group, including an ultra-compact HII region,W3(OH), and at least six more HII regions. The HCO+ (1-0) spectra show the blue-skewed infall asymmetry in the circumcluster envelope, suggesting a large-scale ongoing collapse over 50\" (0.4 pc). The C18O (1-0) emission shows a velocity gradient (0.13 kms-1 arcsec-1) across the W3(OH) region, proposing possible rotation motions over 30\" (0.24 pc). The N2H+ (1-0) emission traces dense and quiescent gas in two filaments. As a first step to describe the infall motions, we utilize RATRAN (Hogerheijde & van der Tak 2000) to analyze our HCO+(1-0) data cube. For the rotation motions, we present a position-velocity diagram and our preliminary estimate gives that the specific angular momentum at 0.06 pc is 0.17 kms -1 pc ( 3.51 x 104 kms -1 AU).

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