Water in massive star-forming regions: HIFI observations of W3 IRS5
Journal article, 2010
We present Herschel observations of the water molecule in the massive star-forming region W3 IRS5. The o-H\_2^17O 1_10-1_01, p-H\_2^18O 1_11-0_00, p-H_2O 2_02-1_11, p-H_2O 1_11-0_00, o-H_2O 2_21-2_12, and o-H_2O 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_2O lines suggests expansion, presumably driven by the outflow. No infall signatures are detected. The p-H_2O 1_11-0_00 and o-H_2O 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 \gsim 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\_2^17O 1_10-1_01 and p-H\_2^18O 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 \lsim 100 K). The possibility of two protostellar objects contributing to the emission is discussed. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.
Author
L. Chavarría
Institut National des Sciences de l'Univers
Laboratoire d'Astrophysique de Bordeaux
F. Herpin
Laboratoire d'Astrophysique de Bordeaux
Institut National des Sciences de l'Univers
T. Jacq
Institut National des Sciences de l'Univers
Laboratoire d'Astrophysique de Bordeaux
J. Braine
Laboratoire d'Astrophysique de Bordeaux
Institut National des Sciences de l'Univers
S. Bontemps
Laboratoire d'Astrophysique de Bordeaux
Institut National des Sciences de l'Univers
A. Baudry
Laboratoire d'Astrophysique de Bordeaux
Institut National des Sciences de l'Univers
M. Marseille
Netherlands Institute for Space Research (SRON)
F. F. S. van der Tak
University of Groningen
Netherlands Institute for Space Research (SRON)
B. Pietropaoli
Institut National des Sciences de l'Univers
Ecole des Mines de Nantes
Laboratoire d'Astrophysique de Bordeaux
F. Wyrowski
Max Planck Society
R. Shipman
Netherlands Institute for Space Research (SRON)
W. Frieswijk
Netherlands Institute for Space Research (SRON)
E. F. van Dishoeck
Leiden University
Max Planck Society
J. Cernicharo
Centro de Astrobiologia (CAB)
R. Bachiller
Spanish National Observatory (OAN)
M. Benedettini
Istituto di Fisica dello Spazio Interplanetario, Rome
A. O. Benz
Swiss Federal Institute of Technology in Zürich (ETH)
E. A. Bergin
University of Michigan
Per Bjerkeli
Chalmers, Department of Radio and Space Science, Radio Astronomy and Astrophysics
G. A. Blake
California Institute of Technology (Caltech)
S. Bruderer
Swiss Federal Institute of Technology in Zürich (ETH)
P. Caselli
University of Leeds
Arcetri Astrophysical Observatory
C. Codella
Arcetri Astrophysical Observatory
F. Daniel
Centro de Astrobiologia (CAB)
A. M. di Giorgio
Istituto di Fisica dello Spazio Interplanetario, Rome
C. Dominik
Anton Pannekoek Institute for Astronomy
Radboud University
S. Doty
Denison University
P. Encrenaz
LERMA - Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique et Atmospheres
M. Fich
University of Waterloo
A. Fuente
Spanish National Observatory (OAN)
T. Giannini
Osservatorio Astronomico di Roma
J. R. Goicoechea
Centro de Astrobiologia (CAB)
T. de Graauw
Netherlands Institute for Space Research (SRON)
P. Hartogh
MPI für Sonnensystemforschung
F. Helmich
Netherlands Institute for Space Research (SRON)
G. J. Herczeg
Max Planck Society
M. R. Hogerheijde
Leiden University
D. Johnstone
University of Victoria
National Research Council Canada
J. K. Jorgensen
University of Copenhagen
L. Kristensen
Leiden University
B. Larsson
Stockholm University
D. Lis
California Institute of Technology (Caltech)
René Liseau
Chalmers, Department of Radio and Space Science, Radio Astronomy and Astrophysics
C. McCoey
Western University
University of Waterloo
G. J. Melnick
Harvard-Smithsonian Center for Astrophysics
B. Nisini
Osservatorio Astronomico di Roma
Michael Olberg
Chalmers, Department of Radio and Space Science, National Facility for Radio Astronomy
B. Parise
Max Planck Society
J. C. Pearson
Jet Propulsion Laboratory, California Institute of Technology
R. Plume
University of Calgary
C. Risacher
Netherlands Institute for Space Research (SRON)
J. Santiago-García
Institut de Radioastronomie Millimétrique (IRAM)
P. Saraceno
Istituto di Fisica dello Spazio Interplanetario, Rome
J. Stutzki
University of Cologne
R. Szczerba
Polish Academy of Sciences
M. Tafalla
Spanish National Observatory (OAN)
A. Tielens
Leiden University
T. A. van Kempen
Harvard-Smithsonian Center for Astrophysics
R. Visser
Leiden University
S. F. Wampfler
Swiss Federal Institute of Technology in Zürich (ETH)
J. Willem
Netherlands Institute for Space Research (SRON)
U. A. Yildiz
Leiden University
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 521 1 L37+- L37Subject Categories
Astronomy, Astrophysics and Cosmology
Roots
Basic sciences
DOI
10.1051/0004-6361/201015113