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dc.creator Butner, H. M.
dc.creator Charnley, S. B.
dc.creator Ceccarelli, C.
dc.creator Rodgers, S. D.
dc.creator Pardo Carrión, Juan Ramón
dc.creator Parise, B.
dc.creator Cernicharo, José
dc.creator Davis, G. R.
dc.date 2007-12-28T13:05:31Z
dc.date 2007-12-28T13:05:31Z
dc.date 2007-04-20
dc.date.accessioned 2017-01-31T00:59:35Z
dc.date.available 2017-01-31T00:59:35Z
dc.identifier The Astrophysical Journal, 659: L137–L140 (2007)
dc.identifier 1538-4357
dc.identifier http://hdl.handle.net/10261/2640
dc.identifier 10.1086/517883
dc.identifier.uri http://dspace.mediu.edu.my:8181/xmlui/handle/10261/2640
dc.description We report the discovery of doubly deuterated water (D2O, heavy water) in the interstellar medium. Using the James Clerk Maxwell Telescope and the Caltech Submillimeter Observatory 10 m telescope, we detected the 1_10–1_01 transition of para-D2O at 316.7998 GHz in both absorption and emission toward the protostellar binary system IRAS 16293-2422. Assuming that the D2O exists primarily in the warm regions where water ices have been evaporated (i.e., in a "hot corino" environment), we determine a total column density of N(D2O) of 1.0x10^13 cm^-2 and a fractional abundance of D2O/H2 = 1.7x10^-10. The derived column density ratios for IRAS 16293-2422 are D2O/HDO = 1.7x10^-3 and D2O/H2O = 5x10^-5 for the hot corino gas. Steady state models of water ice formation, either in the gas phase or on grains, predict D2O/HDO ratios that are about 4 times larger than that derived from our observations. For water formation on grain surfaces to be a viable explanation, a larger H2O abundance than that measured in IRAS 16293-2422 is required. Alternatively, the observed D2O/HDO ratio could be indicative of gas-phase water chemistry prior to a chemical steady state being attained, such as would have occurred during the formation of this source. Future observations with the Herschel Space Observatory satellite will be important for settling this issue.
dc.description The CSO is funded by the NSF through grant AST 22-09008. This work was supported by the NASA Goddard Center for Astrobiology and, through Cooperative Agreement NCC2-1412, by NASA’s Long Term Space Astrophysics Program. J. R. Pardo and J. Cernicharo thank the Spanish MEC for funding support under grant AYA2003-02785 and the Madrid Community Government under grant S-0505 ESP-0237 (ASTROCAM).
dc.description Peer reviewed
dc.format 103233 bytes
dc.format application/pdf
dc.language eng
dc.publisher American Astronomical Society
dc.publisher University of Chicago Press
dc.rights openAccess
dc.subject Astrochemistry
dc.subject ISM: individual (IRAS 16293-2422)
dc.subject ISM: molecules
dc.subject Stars: formation
dc.title Discovery of Interstellar Heavy Water
dc.type Artículo


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