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Description
We study the production of SiO in the gas phase of molecular outflows, through the sputtering of Si-bearing material in grains. The sputtering is driven by neutral particle impact on charged grains in C-type shocks, at the speed corresponding to ambipolar diffusion. Shock speeds in the range 10<v_s_<40km/s and preshock densities 10^4^<n_H_<10^7^cm^-3^ have been investigated. Sputtering of Si-bearing material in both the cores and the mantles of the grains is considered. We find that, for v_s_ of approximately 25km/s and n_H_ of the order 10^5^cm^-3^, column densities of SiO similar to those observed in molecular out flow regions can be generated by either mechanism. Impact by particles heavier than helium dominates the core-sputtering process for shock velocities of this order. The profiles of rotational transitions of SiO are computed and compared with observations of molecular outflows.
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