Where have all the interstellar silicon carbides gone?

The detection of the 11.3-micron emission feature characteristic Si--C stretch in carbon-rich evolved stars reveals that silicon carbide (SiC) dust grains are condensed outflows carbon stars. SiC could be a significant constituent interstellar since it is generally believed inject considerable amount into medium (ISM). presence ISM also supported by identification presolar stellar origin primitive meteorites. However, absorption has never been seen and oxidative destruction often invoked. In this work we quantitatively explore through oxidation based on molecular dynamics simulations density functional theory calculations. We find reaction an oxygen atom with molecules clusters exothermic cause CO-loss. Nevertheless, even if extrapolable to bulk dust, rate still considerably smaller than (currently believed) injection from Therefore, lack remains mystery. A possible solution may lie currently (which have overestimated) and/or size actually submicron size).