Icy molecule desorption in interstellar grain collisions

ABSTRACT Observations of gaseous complex organic molecules (COMs) in cold starless and prestellar cloud cores require efficient desorption the COMs their parent species from icy mantles on interstellar grains. With a simple astrochemical model, we investigate if mechanical removal ice fragments oblique collisions between grains two size bins (0.01 0.1 µm) can substantially affect COM abundances. Two grain collision velocities were considered – 10 50 m s−1, corresponding to realistic relative speeds arising ambipolar diffusion turbulence, respectively. From smaller grains, are assumed remove spherical cap with height equal 1/3 1 mantle thickness, We find that turbulence-induced elevate gas-phase abundances by several orders magnitude, reproducing observed within an order magnitude. Importantly, high attained for long time-scales up Myr rather low methanol abundance, common cores. The considering only assumptions, demonstrates concept must be tested more sophisticated approach.