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

Abstract

[1] 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 thermallyinduced reactions at 50-100 K in solid H 2 O-SO 2 mixtures, reactions that take place without the need for a high-radiation environment. We find that H 2 O and SO 2 react to produce sulfur oxyanions, such as bisulfite, that as much as 30% of the SO 2 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. Citation: Loeffler, M. J., and R. L. Hudson (2010), Thermally-induced chemistry and the Jovian icy satellites: A laboratory study of the formation of sulfur oxyanions, Geophys.

Thermal and energetic processing of astrophysical ice analogues rich in SO2

“…4. For the newly formed bands, we in fact measured a small initial value for the band areas (in agreement with the finding by Moore et al 2007 andLoeffler et al 2010) that we attribute to the thermal reactions induced by the water latent heat of condensation of water ice. When pure SO 2 ice is heated, its sublimation occurs at 120 K as evidenced by a drop in the relative absorption band area (Fig.…”

“…Positions of observed absorption peaks were measured (see Fig. 3) and compared with the position of absorption bands identified in the similar heating experiments of H 2 O:SO 2 icy mixtures performed by Moore et al (2007) and later by Loeffler et al (2010) on different ratios of the same mixture. Our finding for 1:1 and 3:1 mixtures are in excellent agreement with the results of Moore et al (2007).…”

Low-temperature thermal reactions between SO2 and H2O2 and their relevance to the jovian icy satellites

“…In our previous studies with H 2 O + SO 2 ices, we found that these thermal reactions occur in the solid state even at temperatures below 100 K (Loeffler and Hudson, 2010). We now find, in addition, that in the presence of H 2 O 2 the bisulfite is oxidized to form the sulfate (SO 2À 4 ) ion (Martin and Damschen, 1981 ): Fig.…”

Descent without Modification? The Thermal Chemistry of H2O2 on Europa and Other Icy Worlds

“…However, low-temperature thermal processes relevant to Europa have been studied much less frequently. In a recent paper, we described a thermally-driven chemical reaction that can occur at Europa temperatures even in the absence of external photons and ionizing radiation (Loeffler and Hudson, 2010 Thus, the results we reported can be regarded as "hidden chemistry" in that they are changes that will occur at depths greater than those which current instrumentation can probe.…”

“…Table 1 lists the four inorganic compounds we studied. Sulfur dioxide (SO 2 ) was selected since we already have data for it under other conditions (Loeffler and Hudson, 2010;Loeffler and Hudson, 2013), and hydrogen sulfide (H 2 S) was chosen as a possible precursor to SO 2 .…”