Oxygen Chemistry of Shocked Interstellar Clouds. III. Sulfur and Oxygen Species in Dense Clouds
Abstract
The chemical evolution of oxygen and sulfur species in shocked dense clouds is studied. Reaction rate constants for several important neutral reactions are examined, and revised values are suggested. The one-fluid magnetohydrodynamic shock structure and postshock chemical evolution are calculated for shocks of velocity v(s) = 10 km/s through clouds of initial number density n(0) = 100,000/cu cm and of molecule/atom ratios H2/H = 10, 1000, and 100,000 with most sulfur contained initially in molecules SO2 and SO. Abundances of SO2, SO, CS, and OCS remain near their preshock values, except in clouds containing substantial amounts of atomic hydrogen, where significant destruction of sulfur-oxygen species occurs. Abundances of shock-enhanced molecules HS and H2O are sensitive to the molecule/atom ratio. Nonthermal oxygen-hydrogen chemistry has a minor effect on oxygen-sulfur molecules in the case H2/H = 10.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 1988
- DOI:
- 10.1086/166013
- Bibcode:
- 1988ApJ...325..411L
- Keywords:
-
- Interstellar Chemistry;
- Interstellar Matter;
- Molecular Clouds;
- Oxygen;
- Sulfur;
- Chemical Evolution;
- Hydrogen Sulfide;
- Reaction Kinetics;
- Sulfur Oxides;
- Water;
- Astrophysics;
- ATOMIC PROCESSES;
- INTERSTELLAR: MATTER;
- MOLECULAR PROCESSES