Water abundance variations around high-mass protostars: HIFI observations of the DR21 region

WISH team

doi:10.1051/0004-6361/201014515

Water abundance variations around high-mass protostars: HIFI observations of the DR21 region

WISH team

Astrophysics and Planetary Science

30 Citations (Scopus)

Abstract

Context. Water is a key molecule in the star formation process, but its spatial distribution in star-forming regions is not well known. Aims. We study the distribution of dust continuum and H₂O and ¹³CO line emission in DR21, a luminous star-forming region with a powerful outflow and a compact H ii region. Methods. Herschel-HIFI spectra near 1100 GHz show narrow ¹³CO 10-9 emission and H₂O 1₁₁-0₀₀ absorption from the dense core and broad emission from the outflow in both lines. The H₂O line also shows absorption by a foreground cloud known from ground-based observations of low-J CO lines. Results. The dust continuum emission is extended over 36" FWHM, while the ¹³CO and H ₂O lines are confined to ≈ 24" or less. The foreground absorption appears to peak further North than the other components. Radiative transfer models indicate very low abundances of ∼2×10^-10 for H₂O and ∼8×10^-7 for ¹³CO in the dense core, and higher H₂O abundances of ∼4×10^-9 in the foreground cloud and ∼7×10^-7 in the outflow. Conclusions. The high H₂O abundance in the warm outflow is probably due to the evaporation of water-rich icy grain mantles, while the H₂O abundance is kept down by freeze-out in the dense core and by photodissociation in the foreground cloud.

Original language	English
Article number	L107
Journal	Astronomy and Astrophysics
Volume	518
Issue number	4
ISSN	0004-6361
DOIs	https://doi.org/10.1051/0004-6361/201014515
Publication status	Published - 15 Oct 2010

Keywords

astrochemistry
ISM: individual objects: DR21
ISM: molecules
stars: formation

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10.1051/0004-6361/201014515

Cite this

@article{0c51e9a7e57647ca90d4a272271e3ce3,

title = "Water abundance variations around high-mass protostars: HIFI observations of the DR21 region",

abstract = "Context. Water is a key molecule in the star formation process, but its spatial distribution in star-forming regions is not well known. Aims. We study the distribution of dust continuum and H2O and 13CO line emission in DR21, a luminous star-forming region with a powerful outflow and a compact H ii region. Methods. Herschel-HIFI spectra near 1100 GHz show narrow 13CO 10-9 emission and H2O 111-000 absorption from the dense core and broad emission from the outflow in both lines. The H2O line also shows absorption by a foreground cloud known from ground-based observations of low-J CO lines. Results. The dust continuum emission is extended over 36{"} FWHM, while the 13CO and H 2O lines are confined to ≈ 24{"} or less. The foreground absorption appears to peak further North than the other components. Radiative transfer models indicate very low abundances of ∼2×10-10 for H2O and ∼8×10-7 for 13CO in the dense core, and higher H2O abundances of ∼4×10-9 in the foreground cloud and ∼7×10-7 in the outflow. Conclusions. The high H2O abundance in the warm outflow is probably due to the evaporation of water-rich icy grain mantles, while the H2O abundance is kept down by freeze-out in the dense core and by photodissociation in the foreground cloud.",

keywords = "astrochemistry, ISM: individual objects: DR21, ISM: molecules, stars: formation",

author = "{Van Der Tak}, {F. F.S.} and Marseille, {M. G.} and F. Herpin and F. Wyrowski and A. Baudry and S. Bontemps and J. Braine and S. Doty and W. Frieswijk and G. Melnick and R. Shipman and {Van Dishoeck}, {E. F.} and Benz, {A. O.} and P. Caselli and M. Hogerheijde and D. Johnstone and R. Liseau and R. Bachiller and M. Benedettini and E. Bergin and P. Bjerkeli and G. Blake and S. Bruderer and J. Cernicharo and C. Codella and F. Daniel and {Di Giorgio}, {A. M.} and C. Dominik and P. Encrenaz and M. Fich and A. Fuente and T. Giannini and J. Goicoechea and {De Graauw}, Th and F. Helmich and G. Herczeg and J. J{\o}rgensen and L. Kristensen and B. Larsson and D. Lis and C. McCoey and D. Neufeld and B. Nisini and M. Olberg and B. Parise and J. Pearson and R. Plume and C. Risacher and J. Santiago and S. Wampfler and {WISH team}",

year = "2010",

month = oct,

day = "15",

doi = "10.1051/0004-6361/201014515",

language = "English",

volume = "518",

journal = "Astronomy and Astrophysics Supplement Series",

issn = "0004-6361",

publisher = "E D P Sciences",

number = "4",

}

TY - JOUR

T1 - Water abundance variations around high-mass protostars

T2 - HIFI observations of the DR21 region

AU - Van Der Tak, F. F.S.

AU - Marseille, M. G.

AU - Herpin, F.

AU - Wyrowski, F.

AU - Baudry, A.

AU - Bontemps, S.

AU - Braine, J.

AU - Doty, S.

AU - Frieswijk, W.

AU - Melnick, G.

AU - Shipman, R.

AU - Van Dishoeck, E. F.

AU - Benz, A. O.

AU - Caselli, P.

AU - Hogerheijde, M.

AU - Johnstone, D.

AU - Liseau, R.

AU - Bachiller, R.

AU - Benedettini, M.

AU - Bergin, E.

AU - Bjerkeli, P.

AU - Blake, G.

AU - Bruderer, S.

AU - Cernicharo, J.

AU - Codella, C.

AU - Daniel, F.

AU - Di Giorgio, A. M.

AU - Dominik, C.

AU - Encrenaz, P.

AU - Fich, M.

AU - Fuente, A.

AU - Giannini, T.

AU - Goicoechea, J.

AU - De Graauw, Th

AU - Helmich, F.

AU - Herczeg, G.

AU - Jørgensen, J.

AU - Kristensen, L.

AU - Larsson, B.

AU - Lis, D.

AU - McCoey, C.

AU - Neufeld, D.

AU - Nisini, B.

AU - Olberg, M.

AU - Parise, B.

AU - Pearson, J.

AU - Plume, R.

AU - Risacher, C.

AU - Santiago, J.

AU - Wampfler, S.

AU - WISH team

PY - 2010/10/15

Y1 - 2010/10/15

N2 - Context. Water is a key molecule in the star formation process, but its spatial distribution in star-forming regions is not well known. Aims. We study the distribution of dust continuum and H2O and 13CO line emission in DR21, a luminous star-forming region with a powerful outflow and a compact H ii region. Methods. Herschel-HIFI spectra near 1100 GHz show narrow 13CO 10-9 emission and H2O 111-000 absorption from the dense core and broad emission from the outflow in both lines. The H2O line also shows absorption by a foreground cloud known from ground-based observations of low-J CO lines. Results. The dust continuum emission is extended over 36" FWHM, while the 13CO and H 2O lines are confined to ≈ 24" or less. The foreground absorption appears to peak further North than the other components. Radiative transfer models indicate very low abundances of ∼2×10-10 for H2O and ∼8×10-7 for 13CO in the dense core, and higher H2O abundances of ∼4×10-9 in the foreground cloud and ∼7×10-7 in the outflow. Conclusions. The high H2O abundance in the warm outflow is probably due to the evaporation of water-rich icy grain mantles, while the H2O abundance is kept down by freeze-out in the dense core and by photodissociation in the foreground cloud.

AB - Context. Water is a key molecule in the star formation process, but its spatial distribution in star-forming regions is not well known. Aims. We study the distribution of dust continuum and H2O and 13CO line emission in DR21, a luminous star-forming region with a powerful outflow and a compact H ii region. Methods. Herschel-HIFI spectra near 1100 GHz show narrow 13CO 10-9 emission and H2O 111-000 absorption from the dense core and broad emission from the outflow in both lines. The H2O line also shows absorption by a foreground cloud known from ground-based observations of low-J CO lines. Results. The dust continuum emission is extended over 36" FWHM, while the 13CO and H 2O lines are confined to ≈ 24" or less. The foreground absorption appears to peak further North than the other components. Radiative transfer models indicate very low abundances of ∼2×10-10 for H2O and ∼8×10-7 for 13CO in the dense core, and higher H2O abundances of ∼4×10-9 in the foreground cloud and ∼7×10-7 in the outflow. Conclusions. The high H2O abundance in the warm outflow is probably due to the evaporation of water-rich icy grain mantles, while the H2O abundance is kept down by freeze-out in the dense core and by photodissociation in the foreground cloud.

KW - astrochemistry

KW - ISM: individual objects: DR21

KW - ISM: molecules

KW - stars: formation

UR - http://www.scopus.com/inward/record.url?scp=77957799846&partnerID=8YFLogxK

U2 - 10.1051/0004-6361/201014515

DO - 10.1051/0004-6361/201014515

M3 - Journal article

AN - SCOPUS:77957799846

SN - 0004-6361

VL - 518

JO - Astronomy and Astrophysics Supplement Series

JF - Astronomy and Astrophysics Supplement Series

IS - 4

M1 - L107

ER -

Water abundance variations around high-mass protostars: HIFI observations of the DR21 region

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Keywords

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