The distribution of water in the high-mass star-forming region NGC 6334 I
ROLFFS, R.
Université de Cologne, Institut de Physique 1
Max-Planck-Institut für Radioastronomie [MPIFR]
Université de Cologne, Institut de Physique 1
Max-Planck-Institut für Radioastronomie [MPIFR]
CAUX, E.
Centre d'étude spatiale des rayonnements [CESR]
Centre d'étude spatiale des rayonnements [CESR]
Centre d'étude spatiale des rayonnements [CESR]
Centre d'étude spatiale des rayonnements [CESR]
GERIN, M.
Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique [LERMA]
Laboratoire de Radioastronomie [LRA]
Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique [LERMA]
Laboratoire de Radioastronomie [LRA]
HERBST, E.
Ohio State Univ, Dept Phys, Columbus, OH 43210 USA
Ohio State Univ, Dept Astron & Chem, Columbus, OH 43210 USA
Ohio State Univ, Dept Phys, Columbus, OH 43210 USA
Ohio State Univ, Dept Astron & Chem, Columbus, OH 43210 USA
OSSENKOPF, V.
Laboratoire Univers et Théories [LUTH (UMR_8102)]
SRON Netherlands Institute for Space Research [SRON]
Laboratoire Univers et Théories [LUTH (UMR_8102)]
SRON Netherlands Institute for Space Research [SRON]
VASTEL, C.
Centre d'étude spatiale des rayonnements [CESR]
Centre d'étude spatiale des rayonnements [CESR]
< Réduire
Centre d'étude spatiale des rayonnements [CESR]
Centre d'étude spatiale des rayonnements [CESR]
Langue
en
Article de revue
Ce document a été publié dans
Astronomy and Astrophysics - A&A. 2010-10, vol. 521, p. L28
EDP Sciences
Résumé en anglais
Aims: We present observations of twelve rotational transitions of H_216O, H_218O, and H_217O toward the massive star-forming region NGC 6334 I, carried out with Herschel/HIFI as part of the guaranteed time key program ...Lire la suite >
Aims: We present observations of twelve rotational transitions of H_216O, H_218O, and H_217O toward the massive star-forming region NGC 6334 I, carried out with Herschel/HIFI as part of the guaranteed time key program Chemical HErschel Surveys of Star forming regions (CHESS). We analyze these observations to obtain insights into physical processes in this region. Methods: We identify three main gas components (hot core, cold foreground, and outflow) in NGC 6334 I and derive the physical conditions in these components. Results: The hot core, identified by the emission in highly excited lines, shows a high excitation temperature of ~200 K, whereas water in the foreground component is predominantly in the ortho- and para- ground states. The abundance of water varies between 4 × 10-5 (outflow) and 10-8 (cold foreground gas). This variation is most likely due to the freeze-out of water molecules onto dust grains. The H_218O/H_217O abundance ratio is 3.2, which is consistent with the 18O/17O ratio determined from CO isotopologues. The ortho/para ratio in water appears to be relatively low (1.6±1) in the cold, quiescent gas, but close to the equilibrium value of three in the warmer outflow material (2.5±0.8). Herschel is an ESA space observatory with science instruments provided by European-led principal Investigator consortia and with important participation from NASA.Figures 1, 2 and 3 and Tables 2-4 (pages 5 to 6) are only available in electronic form at http://www.aanda.org< Réduire
Mots clés en anglais
stars: formation
ISM: molecules
stars: formation
Origine
Importé de halUnités de recherche