Vastel, C. and Caselli, P. and Ceccarelli, C. and Phillips, T. and Wiedner, M. C. and Peng, R. and Houde, M. and Dominik, C. (2006) The Distribution of Ortho-H_(2)D^(+)(1_(1,0)-1_(1,1)) in L1544: Tracing the Deuteration Factory in Prestellar Cores. Astrophysical Journal, 645 (2). pp. 1198-1211. ISSN 0004-637X http://resolver.caltech.edu/CaltechAUTHORS:20110728-152912536
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Prestellar cores are unique laboratories for studying the chemical and physical conditions preceding star formation. We observed the prestellar core L1544 in the fundamental transition of ortho-H_(2)D^(+)(1_(1,0)-1_(1,1)) at different positions over 100" and found a strong correlation between its abundance and the CO depletion factor. We also present a tentative detection of the fundamental transition of para-D_(2)H^+ (1_(1,0)-1_(0,1)) at the dust emission peak. Maps in N_(2)H^+, N_(2)D^+, HCO^+, and DCO^+ are used and interpreted with the aid of a spherically symmetric chemical model that predicts the column densities and abundances of these species as a function of radius. The correlation between the observed deuterium fractionation of H^(+)_3, N_(2)H^+, and HCO^+ and the observed integrated CO depletion factor across the core can be reproduced by this chemical model. In addition, a simpler model is used to study the H_(2)D^+ ortho-to-para ratio. We conclude that, in order to reproduce the observed ortho-H_(2)D^+ observations, the grain radius should be larger than 0.3 μm.
|Additional Information:||© 2006 American Astronomical Society. Received 2006 January 24; accepted 2006 March 17. The authors thank the staff of the CSO telescope for their support. C. V. is grateful to Malcom Walmsley and Guillaume Pineau des Forets for fruitful discussions and to Laurent Pagani for useful comments. P. C. acknowledges support fromthe MIUR grant "Dust Particles as Factors of Galactic Evolution." This research has been supported by NSF grant AST 05-40882 to the CSO. Facilities: CSO|
|Subject Keywords:||ISM: individual (L1544); ISM: molecules; radio lines: ISM|
|Official Citation:||The Distribution of Ortho-H2D+(11,0-11,1) in L1544: Tracing the Deuteration Factory in Prestellar Cores C. Vastel et al. 2006 ApJ 645 1198|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Jason Perez|
|Deposited On:||01 Aug 2011 14:48|
|Last Modified:||26 Dec 2012 13:25|
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