Volume 517, July 2010
|Number of page(s)||4|
|Published online||04 August 2010|
Letter to the Editor
The NH2D/NH3 ratio toward pre-protostellar cores around the UC region in IRAS 20293+3952*
Departament d'Astronomia i Meteorologia (IEEC-UB), Institut de Ciències del Cosmos, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain e-mail: email@example.com
2 Institut de Ciències de l'Espai (CSIC-IEEC), Campus UAB, Facultat de Ciències, Torre C-5 parell, 08193 Bellaterra, Spain
3 Department of Physics and Astronomy, University College London, Grower Street, London WC1E 6BT, UK
4 Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, 02138, USA
5 Academia Sinica Institute of Astronomy and Astrophysics, Taipei, Taiwan
Accepted: 16 June 2010
Context. The deuterium fractionation, , has been proposed as an evolutionary indicator in pre-protostellar and protostellar cores of low-mass star-forming regions.
Aims. We investigate , with high angular resolution, in the cluster environment surrounding the UC region IRAS 20293+3952.
Methods. We performed high angular resolution observations with the IRAM Plateau de Bure Interferometer (PdBI) of the ortho-NH2D 111–101 line at 85.926 GHz and compared them with previously reported VLA NH3 data.
Results. We detected strong NH2D emission toward the pre-protostellar cores identified in NH3 and dust emission, all located in the vicinity of the UC region IRAS 20293+3952. We found high values of 0.1–0.8 in all the pre-protostellar cores and low values, < 0.1, associated with young stellar objects.
Conclusions. The high values of in pre-protostellar cores could be indicative of evolution, although outflow interactions and UV radiation could also play a role.
Key words: stars: formation / ISM: individual objects: IRAS 20293+3952 / ISM: clouds / ISM: molecules
© ESO, 2010
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