The DCN / HCN abundance ratio in hot molecular coresJ
نویسندگان
چکیده
We have observed the 3-2 transitions of DCN and HC 15 N in a number of hot molecular cores previously surveyed by us with the interesting result that the DCN/HCN ratio is low, a few times 10 ?3 , in the hot cores. The abundance ratio of DCN/HCN is derived bothòn-core' andòo-core' and, in general is larger at thèoo-core' positions. Comparision with chemical models of these sources indicates that DCN liberated from evaporated ices can be destroyed rapidly in the hot gas by reaction with atomic hydrogen, which works to reset the the initial DCN/HCN ratio in the ice to the gas-phase atomic D/H ratio. The low DCN/HCN abundance ratio we measure can be reached in less than 10 4 years, consistent with previous estimates of the core ages, if the activation energy of the reaction is less than 500 K.
منابع مشابه
The DCN / HCN abundance ratio in hot molecular cores
We have observed the 3-2 transitions of DCN and HC 15 N in a number of hot molecular cores previously surveyed by us with the interesting result that the DCN/HCN ratio is low, a few times 10 −3 , in the hot cores. The abundance ratio of DCN/HCN is derived both 'on-core' and 'off-core' and, in general is larger at the 'off-core' positions. Comparision with chemical models of these sources indica...
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