Journal Article

The molecular emissions and the infall motion in the high-mass young stellar object G8.68−0.37

Zhiyuan Ren, Yuefang Wu, Ming Zhu, Tie Liu, Ruisheng Peng, Shengli Qin and Lixin Li

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 422, issue 2, pages 1098-1108
Published in print May 2012 | ISSN: 0035-8711
Published online April 2012 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2012.20683.x
The molecular emissions and the infall motion in the high-mass young stellar object G8.68−0.37

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We present a multi-wavelength observational study towards the high-mass young stellar object G8.68−0.37. A single massive gas-and-dust core is observed in the (sub)millimetre continuum and molecular line emissions. We fitted the spectral energy distribution (SED) from the dust continuum emission. The best-fitting SED suggests the presence of two components with temperature of Td= 20 and 120 K, respectively. The core has a total mass of up to 1.5 × 103 M and a bolometric luminosity of 2.3 × 104 L. Both the mass and luminosity are dominated by the cold component (Td= 20 K). The molecular lines of C18O, C34S, DCN and thermally excited CH3OH are detected in this core. Prominent infall signatures are observed in the 12CO (1 − 0) and (2 − 1). We estimated an infall velocity of 0.45 km s−1 and a mass infall rate of 7 × 10−4 M yr−1. From the molecular lines, we have found a high DCN-to-HCN abundance ratio of 0.07. The overabundant DCN may originate from a significant deuteration in the previous cold pre-protostellar phase. And the DCN should now be rapidly sublimated from the grain mantles to maintain the overabundance in the gas phase.

Keywords: stars: formation; stars: pre-main sequence; ISM: individual object: G8.68−0.37; ISM: kinematics and dynamics; ISM: molecules

Journal Article.  7741 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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