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Chemistry in Shocked Interstellar Gas

Published online by Cambridge University Press:  04 August 2017

George F. Mitchell
George F. Mitchell*
Affiliation:
Department of Astronomy, Saint Mary's University, Halifax, N. S., B3H 3C3 Canada

Abstract

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In its passage through the interstellar gas, a shock imposes massive and irreversible changes on the chemical composition of the gas. The synthesis of molecules from atoms and atomic ions can be highly efficient behind non-dissociative (i.e. slow) shocks. Results of kinetic calculations behind non-dissociative shocks are reviewed here, with emphasis given to the dependence of the postshock molecular composition on initial cloud properties. It is shown that a dense cloud shock can convert essentially all neutral atoms into various molecules. Even in diffuse and unshielded regions, a variety of molecules can attain a high abundance behind shocks. The suggestion that the widespread diffuse cloud species CH+ is shock synthesized is critically examined in the light of new calculations.

Type
Interstellar Medium
Information
Symposium - International Astronomical Union , Volume 120: Astrochemistry , 1987 , pp. 275 - 287
Copyright
Copyright © Reidel 1987 

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