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Hydrides in young stellar objects: Radiation tracers in a protostar-disk-outflow system

Benz, A. O. and Blake, G. A. and Lis, D. (2010) Hydrides in young stellar objects: Radiation tracers in a protostar-disk-outflow system. Astronomy and Astrophysics, 521 . Art. No. L35. ISSN 0004-6361.

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Context. Hydrides of the most abundant heavier elements are fundamental molecules in cosmic chemistry. Some of them trace gas irradiated by UV or X-rays. Aims. We explore the abundances of major hydrides in W3 IRS5, a prototypical region of high-mass star formation. Methods. W3 IRS5 was observed by HIFI on the Herschel Space Observatory with deep integration (≃2500 s) in 8 spectral regions. Results. The target lines including CH, NH, H_3O^+, and the new molecules SH^+, H_2O^+, and OH^+ are detected. The H2O^+ and OH^+ J = 1−0 lines are found mostly in absorption, but also appear to exhibit weak emission (P-Cyg-like). Emission requires high density, thus originates most likely near the protostar. This is corroborated by the absence of line shifts relative to the young stellar object (YSO). In addition, H2O^+ and OH^+ also contain strong absorption components at a velocity shifted relative to W3 IRS5, which are attributed to foreground clouds. Conclusions. The molecular column densities derived from observations correlate well with the predictions of a model that assumes the main emission region is in outflow walls, heated and irradiated by protostellar UV radiation.

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 14 July 2010, Published online 01 October 2010. Herschel is an ESA space observatory with science instruments provided by a European-led Principal Investigator consortia and with important participation from NASA. Appendix (page 5) is only available in electronic form at We thank Michael Kaufman and Serena Viti for helpful comments on an early draft. This program is made possible thanks to the Swiss Herschel guaranteed time program. 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 Astronomico Nacional (IGN), Centro de Astrobiologia (CSICINT); Sweden: Chalmers University of Technology, Onsala Space Observatory, Swedish National Space Board, Stockholm University; Switzerland: ETH Zurich, FHNW; USA: Caltech, JPL, NHSC. The work on star formation at ETH Zurich is partially funded by the Swiss National Science Foundation (grant no. 200020-113556).
Funding AgencyGrant Number
Swiss National Science Foundation (SNSF)200020-113556
Subject Keywords:astrochemistry – line: identification – stars: formation – stars: massive – photon-dominated region – submillimeter: ISM
Record Number:CaltechAUTHORS:20101220-105943371
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Official Citation:Hydrides in young stellar objects: Radiation tracers in a protostar-disk-outflow system A. O. Benz, S. Bruderer, E. F. van Dishoeck, P. Stäuber, S. F. Wampfler, M. Melchior, C. Dedes, F. Wyrowski, S. D. Doty, F. van der Tak, W. Bächtold, A. Csillaghy, A. Megej, C. Monstein, M. Soldati, R. Bachiller, A. Baudry, M. Benedettini, E. Bergin, P. Bjerkeli, G. A. Blake, S. Bontemps, J. Braine, P. Caselli, J. Cernicharo, C. Codella, F. Daniel, A. M. di Giorgio, P. Dieleman, C. Dominik, P. Encrenaz, M. Fich, A. Fuente, T. Giannini, J. R. Goicoechea, Th. de Graauw, F. Helmich, G. J. Herczeg, F. Herpin, M. R. Hogerheijde, T. Jacq, W. Jellema, D. Johnstone, J. K. Jørgensen, L. E. Kristensen, B. Larsson, D. Lis, R. Liseau, M. Marseille, C. McCoey, G. Melnick, D. Neufeld, B. Nisini, M. Olberg, V. Ossenkopf, B. Parise, J. C. Pearson, R. Plume, C. Risacher, J. Santiago-García, P. Saraceno, R. Schieder, R. Shipman, J. Stutzki, M. Tafalla, A. G. G. M. Tielens, T. A. van Kempen, R. Visser and U. A. Yıldız A&A 521 L35 (2010) DOI: 10.1051/0004-6361/201015111
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:21435
Deposited By: Benjamin Perez
Deposited On:20 Dec 2010 19:33
Last Modified:03 Oct 2019 02:24

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