Thermally-induced chemistry and the Jovian icy satellites: A laboratory study of the formation of sulfur oxyanions

Laboratory experiments have demonstrated that magnetospheric radiation in the Jovian system drives reaction chemistry in ices at temperatures relevant to Europa and other icy satellites. Here we present new results on thermally-induced reactions at 50-100 K in solid H₂O-SO₂ mixtures, reactions that take place without the need for a high-radiation environment. We find that H₂O and SO₂ react to produce sulfur oxyanions, such as bisulfite, that as much as 30% of the SO₂ can be consumed through this reaction, and that the products remain in the ice when the temperature is lowered, indicating that these reactions are irreversible. Our results suggest that thermally-induced reactions can alter the chemistry at temperatures relevant to the icy satellites in the Jovian system.