Herschel/HIFI detections of hydrides towards AFGL 2591 Envelope emission versus tenuous cloud absorption
Journal article, 2010
The Heterodyne Instrument for the Far Infrared (HIFI) onboard the Herschel Space Observatory allows the first observations of light diatomic molecules at high spectral resolution and in multiple transitions. Here, we report deep integrations using HIFI in different lines of hydrides towards the high-mass star forming region AFGL 2591. Detected are CH, CH+, NH, OH+, H2O+, while NH+ and SH+ have not been detected. All molecules except for CH and CH+ are seen in absorption with low excitation temperatures and at velocities different from the systemic velocity of the protostellar envelope. Surprisingly, the CH(J(F,P) = 3/2(2),(-) - 1/2(1,+)) and CH+(J = 1-0, J = 2-1) lines are detected in emission at the systemic velocity. We can assign the absorption features to a foreground cloud and an outflow lobe, while the CH and CH+ emission stems from the envelope. The observed abundance and excitation of CH and CH+ can be explained in the scenario of FUV irradiated outflow walls, where a cavity etched out by the outflow allows protostellar FUV photons to irradiate and heat the envelope at larger distances driving the chemical reactions that produce these molecules.
ISM: individual objects: AFGL 2591
ISM: molecules
stars: formation
astrochemistry
Author
S. Bruderer
Swiss Federal Institute of Technology in Zürich (ETH)
A. O. Benz
University of Applied Sciences and Arts Northwestern Switzerland
E. F. van Dishoeck
Leiden University
M. Melchior
University of Applied Sciences and Arts Northwestern Switzerland
S. Doty
Denison University
F. F. S. van der Tak
University of Groningen
P. Stauber
Swiss Federal Institute of Technology in Zürich (ETH)
S. F. Wampfler
University of Bern
C. Dedes
Swiss Federal Institute of Technology in Zürich (ETH)
U. A. Yildiz
Jet Propulsion Laboratory, California Institute of Technology
L. Pagani
Sorbonne University
T. Giannini
Osservatorio Astronomico di Roma
T. de Graauw
Leiden University
N. Whyborn
Cherenkov Telescope Array
D. Teyssier
European Space Agency (ESA)
W. Jellema
Netherlands Institute for Space Research (SRON)
R. Shipman
Netherlands Institute for Space Research (SRON)
R. Schieder
University of Cologne
N. Honingh
University of Cologne
E. Caux
Paul Sabatier University
W. Bachtold
Swiss Federal Institute of Technology in Zürich (ETH)
A. Csillaghy
University of Applied Sciences and Arts Northwestern Switzerland
C. Monstein
Istituto Ricerche Solari Locarno
R. Bachiller
Spanish National Observatory (OAN)
A. Baudry
University of Bordeaux
M. Benedettini
Istituto nazionale di astrofisica (INAF)
E. A. Bergin
University of Michigan
Per Bjerkeli
Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics
G. A. Blake
California Institute of Technology (Caltech)
S. Bontemps
University of Bordeaux
J. Braine
University of Bordeaux
P. Caselli
Max Planck Institute for Extraterrestrial Physics
J. Cernicharo
CSIC - Instituto de Fisica Fundamental (IFF)
C. Codella
Arcetri Astrophysical Observatory
F. Daniel
Grenoble Alpes University
A. M. di Giorgio
Istituto nazionale di astrofisica (INAF)
C. Dominik
Sterrenkundig Instituut Anton Pannekoek
P. Encrenaz
Paris Observatory
M. Fich
University of Waterloo
A. Fuente
Spanish National Observatory (OAN)
J. R. Goicoechea
CSIC - Instituto de Fisica Fundamental (IFF)
F. Helmich
University of Groningen
G. J. Herczeg
Peking University
F. Herpin
University of Bordeaux
M. R. Hogerheijde
University of Amsterdam
T. Jacq
University of Bordeaux
D. Johnstone
University of Victoria
J. K. Jorgensen
University of Copenhagen
L. Kristensen
Niels Bohr Institute
B. Larsson
Stockholm University
D. Lis
Jet Propulsion Laboratory, California Institute of Technology
René Liseau
Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics
M. Marseille
Centre National d'Etudes Spatiales (CNES)
C. McCoey
University of Waterloo
G. J. Melnick
Harvard-Smithsonian Center for Astrophysics
D. A. Neufeld
Johns Hopkins University
B. Nisini
Osservatorio Astronomico di Roma
Michael Olberg
Chalmers, Earth and Space Sciences, Onsala Space Observatory
B. Parise
Max-Planck Institute for Radio Astronomy
J. C. Pearson
Jet Propulsion Laboratory, California Institute of Technology
R. Plume
University of Calgary
C. Risacher
Institut de Radioastronomie Millimétrique (IRAM)
J. Santiago-García
Instituto de Radioastronomía Milimétrica
P. Saraceno
Istituto nazionale di astrofisica (INAF)
M. Tafalla
Spanish National Observatory (OAN)
T. A. van Kempen
Netherlands Institute for Space Research (SRON)
R. Visser
European Southern Observatory (ESO)
F. Wyrowski
Max-Planck Institute for Radio Astronomy
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 521 1 L44Subject Categories
Astronomy, Astrophysics and Cosmology
DOI
10.1051/0004-6361/201015098