Variations in H2O+/H2O ratios toward massive star-forming regions
Journal article, 2010
Early results from the Herschel Space Observatory revealed the water cation H2O+ to be an abundant ingredient of the interstellar medium. Here we present new observations of the H2O and H2O+ lines at 1113.3 and 1115.2 GHz using the Herschel Space Observatory toward a sample of high-mass star-forming regions to observationally study the relation between H2O and H2O+. Nine out of ten sources show absorption from H2O+ in a range of environments: the molecular clumps surrounding the forming and newly formed massive stars, bright high-velocity outflows associated with the massive protostars, and unrelated low-density clouds along the line of sight. Column densities per velocity component of H2O+ are found in the range of 10^12 to a few 10^13 cm^-2. The highest N(H2O+) column densities are found in the outflows of the sources. The ratios of H2O+/H2O are determined in a range from 0.01 to a few and are found to differ strongly between the observed environments with much lower ratios in the massive (proto)cluster envelopes (0.01-0.1) than in outflows and diffuse clouds. Remarkably, even for source components detected in H2O in emission, H2O+ is still seen in absorption. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.
ISM: molecules
ISM: clouds
submillimeter: ISM
stars: formation
Author
F. Wyrowski
Max Planck Society
F. F. S. van der Tak
University of Groningen
Netherlands Institute for Space Research (SRON)
F. Herpin
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
S. Bontemps
Laboratoire d'Astrophysique de Bordeaux
Institut National des Sciences de l'Univers
L. Chavarría
Laboratoire d'Astrophysique de Bordeaux
Institut National des Sciences de l'Univers
W. Frieswijk
University of Groningen
T. Jacq
Laboratoire d'Astrophysique de Bordeaux
Institut National des Sciences de l'Univers
M. Marseille
Netherlands Institute for Space Research (SRON)
R. Shipman
Netherlands Institute for Space Research (SRON)
E. F. van Dishoeck
Max Planck Society
Leiden University
A. O. Benz
Swiss Federal Institute of Technology in Zürich (ETH)
P. Caselli
University of Leeds
M. R. Hogerheijde
Leiden University
D. Johnstone
University of Victoria
National Research Council Canada
René Liseau
Chalmers, Department of Radio and Space Science, Radio Astronomy and Astrophysics
R. Bachiller
Spanish National Observatory (OAN)
M. Benedettini
University of Michigan
University of Rome Tor Vergata
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)
J. Braine
Institut National des Sciences de l'Univers
Laboratoire d'Astrophysique de Bordeaux
S. Bruderer
Swiss Federal Institute of Technology in Zürich (ETH)
J. Cernicharo
Centro de Astrobiologia (CAB)
C. Codella
University of Rome Tor Vergata
F. Daniel
Agencia Estatal Consejo Superior de Investigaciones Científicas (CSIC)
LERMA - Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique et Atmospheres
A. M. di Giorgio
University of Rome Tor Vergata
C. Dominik
Anton Pannekoek Institute for Astronomy
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
University of Rome Tor Vergata
J. R. Goicoechea
Centro de Astrobiologia (CAB)
T. de Graauw
Atacama Large Millimeter-submillimeter Array (ALMA)
F. Helmich
Netherlands Institute for Space Research (SRON)
G. J. Herczeg
Max Planck Society
J. K. Jorgensen
University of Copenhagen
L. Kristensen
Leiden University
B. Larsson
Stockholm University
D. Lis
California Institute of Technology (Caltech)
C. McCoey
University of Waterloo
G. J. Melnick
Harvard-Smithsonian Center for Astrophysics
B. Nisini
University of Rome Tor Vergata
Michael Olberg
Chalmers, Department of Radio and Space Science, Radio Astronomy and Astrophysics
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
Spanish National Observatory (OAN)
P. Saraceno
University of Rome Tor Vergata
M. Tafalla
Spanish National Observatory (OAN)
T. A. van Kempen
Harvard-Smithsonian Center for Astrophysics
R. Visser
Leiden University
S. F. Wampfler
Swiss Federal Institute of Technology in Zürich (ETH)
U. A. Yildiz
Leiden University
John H Black
Chalmers, Department of Radio and Space Science, Radio Astronomy and Astrophysics
E. Falgarone
LERMA - Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique et Atmospheres
M. Gerin
LERMA - Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique et Atmospheres
P. Roelfsema
Netherlands Institute for Space Research (SRON)
P. Dieleman
Netherlands Institute for Space Research (SRON)
D. Beintema
Netherlands Institute for Space Research (SRON)
A. de Jonge
Netherlands Institute for Space Research (SRON)
N. Whyborn
Atacama Large Millimeter-submillimeter Array (ALMA)
J. Stutzki
University of Cologne
V. Ossenkopf
University of Cologne
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 521 1 L34+- L34Subject Categories
Astronomy, Astrophysics and Cosmology
Roots
Basic sciences
DOI
10.1051/0004-6361/201015110