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Water in massive star-forming regions: HIFI observations of W3 IRS5

Chavarría, L. and Blake, G. A. and Lis, D. (2010) Water in massive star-forming regions: HIFI observations of W3 IRS5. Astronomy and Astrophysics, 521 . L37. ISSN 0004-6361.

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We present Herschel observations of the water molecule in the massive star-forming region W3 IRS5. The o-H_(2)^(17)O 1_(10)-1_(01), p-H_(2_^(18)O 1_(11)-0_(00), p-H_(2)O 2_(02)-1_(11), p-H_(2)O 1_(11)-0_(00), o-H_(2)O 2_(21)-2_(12), and o-H_(2)O 2_(12)-1_(01) lines, covering a frequency range from 552 up to 1669 GHz, have been detected at high spectral resolution with HIFI. The water lines in W3 IRS5 show well-defined high-velocity wings that indicate a clear contribution by outflows. Moreover, the systematically blue-shifted absorption in the H_(2)_O lines suggests expansion, presumably driven by the outflow. No infall signatures are detected. The p-H_(2)O 1_(11)-0_(00) and o-H_(2)O 2_(12)-1_(01) lines show absorption from the cold material (T ~ 10 K) in which the high-mass protostellar envelope is embedded. One-dimensional radiative transfer models are used to estimate water abundances and to further study the kinematics of the region. We show that the emission in the rare isotopologues comes directly from the inner parts of the envelope (T ≳ 100 K) where water ices in the dust mantles evaporate and the gas-phase abundance increases. The resulting jump in the water abundance (with a constant inner abundance of 10^(-4)) is needed to reproduce the o-H_(2)^(17)O 1_(10)-1_(01) and p-H_(2)^(18)O 1_(11)-0_(00) spectra in our models. We estimate water abundances of 10^(-8) to 10^(-9) in the outer parts of the envelope (T ≲ 100 K). The possibility of two protostellar objects contributing to the emission is discussed.

Item Type:Article
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Blake, G. A.0000-0003-0787-1610
Lis, D.0000-0002-0500-4700
Additional Information:© 2010 ESO. Received 31 May 2010; Accepted 20 July 2010; Published online 01 October 2010. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. HIFI has been designed and built by a consortium of institutes and university departments from across Europe, Canada, and the United States under the leadership of SRON Netherlands Institute for Space Research, Groningen, The Netherlands, and with major contributions from Germany, France, and the US. Consortium members are: Canada: CSA, U. Waterloo; France: CESR, LAB, LERMA, IRAM; Germany: KOSMA, MPIfR, MPS; Ireland, NUI Maynooth; Italy: ASI, IFSI-INAF, Osservatorio Astrofisico di Arcetri- INAF; Netherlands: SRON, TUD; Poland: CAMK, CBK; Spain: Observatorio Astronómico Nacional (IGN), Centro de Astrobiología (CSIC-INTA). Sweden: Chalmers University of Technology – MC2, RSS & GARD; Onsala Space Observatory; Swedish National Space Board, Stockholm University – Stockholm Observatory; Switzerland: ETH Zurich, FHNW; USA: Caltech, JPL, NHSC. HIPE is a joint development by the Herschel Science Ground Segment Consortium, consisting of ESA, the NASA Herschel Science Center, and the HIFI, PACS and SPIRE consortia. We also thank the French Space Agency CNES for financial support.
Funding AgencyGrant Number
Centre National d'Études Spatiales (CNES)UNSPECIFIED
Subject Keywords:stars: formation; stars: massive; ISM: molecules; ISM: abundances; dust, extinction; radio lines: ISM
Record Number:CaltechAUTHORS:20101213-112701463
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Official Citation:Water in massive star-forming regions: HIFI observations of W3 IRS5 L. Chavarría, F. Herpin, T. Jacq, J. Braine, S. Bontemps, A. Baudry, M. Marseille, F. van der Tak, B. Pietropaoli, F. Wyrowski, R. Shipman, W. Frieswijk, E. F. van Dishoeck, J. Cernicharo, R. Bachiller, M. Benedettini, A. O. Benz, E. Bergin, P. Bjerkeli, G. A. Blake, S. Bruderer, P. Caselli, C. Codella, F. Daniel, A. M. di Giorgio, C. Dominik, S. D. Doty, P. Encrenaz, M. Fich, A. Fuente, T. Giannini, J. R. Goicoechea, Th. de Graauw, P. Hartogh, F. Helmich, G. J. Herczeg, M. R. Hogerheijde, D. Johnstone, J. K. Jørgensen, L. E. Kristensen, B. Larsson, D. Lis, R. Liseau, C. McCoey, G. Melnick, B. Nisini, M. Olberg, B. Parise, J. C. Pearson, R. Plume, C. Risacher, J. Santiago-García, P. Saraceno, J. Stutzki, R. Szczerba, M. Tafalla, A. Tielens, T. A. van Kempen, R. Visser, S. F. Wampfler, J. Willem and U. A. Yıldız A&A 521 L37 (2010) DOI: 10.1051/0004-6361/201015113
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:21320
Deposited By: Jason Perez
Deposited On:20 Dec 2010 21:17
Last Modified:03 Oct 2019 02:22

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