Water abundances in high-mass protostellar envelopes: Herschel observations with HIFI
Artikel i vetenskaplig tidskrift, 2010

Aims: We derive the dense core structure and the water abundance in four massive star-forming regions in the hope of understanding the earliest stages of massive star formation. Methods: We present Herschel/HIFI observations of the para-H_2O 1_11-0_00 and 2_02-1_11 and the para-H\_2^18O 1_11-0_00 transitions. The envelope contribution to the line profiles is separated from contributions by outflows and foreground clouds. The envelope contribution is modeled with Monte-Carlo radiative transfer codes for dust and molecular lines (MC3D and RATRAN), and the water abundance and the turbulent velocity width as free parameters. Results: While the outflows are mostly seen in emission in high-J lines, envelopes are seen in absorption in ground-state lines, which are almost saturated. The derived water abundances range from 5\times10^-10 to 4\times10^-8 in the outer envelopes. We detect cold clouds surrounding the protostar envelope, thanks to the very high quality of the Herschel/HIFI data and the unique ability of water to probe them. Several foreground clouds are also detected along the line of sight. Conclusions: The low H_2O abundances in massive dense cores are in accordance with the expectation that high densities and low temperatures lead to freeze-out of water on dust grains. The spread in abundance values is not clearly linked to physical properties of the sources.

Författare

M. G. Marseille

Netherlands Institute for Space Research (SRON)

F. F. S. van der Tak

Rijksuniversiteit Groningen

Netherlands Institute for Space Research (SRON)

F. Herpin

Laboratoire d'Astrophysique de Bordeaux

Institut National des Sciences de l'Univers

F. Wyrowski

Max Planck-institutet

L. Chavarría

Institut National des Sciences de l'Univers

Laboratoire d'Astrophysique de Bordeaux

B. Pietropaoli

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

Institut National des Sciences de l'Univers

Laboratoire d'Astrophysique de Bordeaux

J. Cernicharo

Centro de Astrobiologia (CAB)

T. Jacq

Osservatorio Astrofisico di Arcetri

W. Frieswijk

Netherlands Institute for Space Research (SRON)

R. Shipman

Netherlands Institute for Space Research (SRON)

E. F. van Dishoeck

Max Planck-institutet

Universiteit Leiden

R. Bachiller

Observatorio Astronamico Nacional (OAN-IGN)

M. Benedettini

Universita degli Studi di Roma Tor Vergata

A. O. Benz

Eidgenössische Technische Hochschule Zürich (ETH)

E. A. Bergin

University of Michigan

Per Bjerkeli

Chalmers, Institutionen för radio- och rymdvetenskap, Radioastronomi och astrofysik

G. A. Blake

Caltech Division of Geological and Planetary Sciences

J. Braine

Laboratoire d'Astrophysique de Bordeaux

Institut National des Sciences de l'Univers

S. Bruderer

Osservatorio Astrofisico di Arcetri

University of Leeds

P. Caselli

Institut National des Sciences de l'Univers

Caltech Division of Geological and Planetary Sciences

Laboratoire d'Astrophysique de Bordeaux

E. Caux

Institut National des Sciences de l'Univers

Université de Toulouse

C. Codella

Osservatorio Astrofisico di Arcetri

F. Daniel

Centro de Astrobiologia (CAB)

P. Dieleman

Netherlands Institute for Space Research (SRON)

A. M. di Giorgio

Universita degli Studi di Roma Tor Vergata

C. Dominik

Anton Pannekoek Institute for Astronomy

Radboud Universiteit

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 Astronamico Nacional (OAN-IGN)

T. Gaier

Jet Propulsion Laboratory, California Institute of Technology

T. Giannini

Osservatorio Astronomico di Roma

J. R. Goicoechea

Centro de Astrobiologia (CAB)

T. de Graauw

Netherlands Institute for Space Research (SRON)

F. Helmich

Netherlands Institute for Space Research (SRON)

G. J. Herczeg

Max Planck-institutet

M. R. Hogerheijde

Universiteit Leiden

B. Jackson

Netherlands Institute for Space Research (SRON)

H. Javadi

Jet Propulsion Laboratory, California Institute of Technology

W. Jellema

Netherlands Institute for Space Research (SRON)

D. Johnstone

National Research Council Canada

University of Victoria

J. K. Jorgensen

Köbenhavns Universitet

D. Kester

Netherlands Institute for Space Research (SRON)

L. Kristensen

Universiteit Leiden

B. Larsson

Stockholms universitet

W. Laauwen

Netherlands Institute for Space Research (SRON)

D. Lis

CalTech

René Liseau

Chalmers, Institutionen för radio- och rymdvetenskap, Radioastronomi och astrofysik

W. Luinge

Netherlands Institute for Space Research (SRON)

C. McCoey

Western University

University of Waterloo

A. Megej

Eidgenössische Technische Hochschule Zürich (ETH)

G. J. Melnick

Harvard-Smithsonian Center for Astrophysics

D. A. Neufeld

Johns Hopkins University

B. Nisini

Osservatorio Astronomico di Roma

Michael Olberg

Chalmers, Institutionen för radio- och rymdvetenskap, Nationella anläggningen för radioastronomi

B. Parise

Max Planck-institutet

J. C. Pearson

Jet Propulsion Laboratory, California Institute of Technology

R. Plume

University of Calgary

C. Risacher

Netherlands Institute for Space Research (SRON)

P. Roelfsema

Netherlands Institute for Space Research (SRON)

J. Santiago-García

Instituto de Radioastronomia Milimetrica

P. Saraceno

Universita degli Studi di Roma Tor Vergata

P. Siegel

Jet Propulsion Laboratory, California Institute of Technology

J. Stutzki

Universität zu Köln

M. Tafalla

Observatorio Astronamico Nacional (OAN-IGN)

T. A. van Kempen

Harvard-Smithsonian Center for Astrophysics

R. Visser

Universiteit Leiden

S. F. Wampfler

Eidgenössische Technische Hochschule Zürich (ETH)

U. A. Yildiz

Universiteit Leiden

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 521 1 L32+- L32

Ämneskategorier

Astronomi, astrofysik och kosmologi

Fundament

Grundläggande vetenskaper

DOI

10.1051/0004-6361/201015103

Mer information

Senast uppdaterat

2018-09-06