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: clouds

stars: formation

submillimeter: ISM

ISM: molecules

Author

F. Wyrowski

Max Planck Institute

F. F. S. van der Tak

Netherlands Institute for Space Research (SRON)

University of Groningen

F. Herpin

Institut National des Sciences de l'Univers

Laboratoire d'Astrophysique de Bordeaux

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

Institut National des Sciences de l'Univers

Laboratoire d'Astrophysique de Bordeaux

M. Marseille

Netherlands Institute for Space Research (SRON)

R. Shipman

Netherlands Institute for Space Research (SRON)

E. F. van Dishoeck

Max Planck Institute

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

National Research Council Canada

University of Victoria

René Liseau

Chalmers, Department of Radio and Space Science, Radio Astronomy and Astrophysics

R. Bachiller

Observatorio Astronomico Nacional

M. Benedettini

University of Rome Tor Vergata

University of Michigan

E. A. Bergin

University of Michigan

Per Bjerkeli

Chalmers, Department of Radio and Space Science, Radio Astronomy and Astrophysics

G. A. Blake

Caltech Division of Geological and Planetary Sciences

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

Consejo Superior de Investigaciones Científicas

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

Observatorio Astronomico Nacional

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 Institute

J. K. Jorgensen

Köbenhavns Universitet

L. Kristensen

Leiden University

B. Larsson

Stockholm University

D. Lis

Caltech Division of Geological and Planetary Sciences

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 Institute

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

Observatorio Astronomico Nacional

P. Saraceno

University of Rome Tor Vergata

M. Tafalla

Observatorio Astronomico Nacional

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+- L34

Subject Categories

Astronomy, Astrophysics and Cosmology

Roots

Basic sciences

DOI

10.1051/0004-6361/201015110