Removal of Titan's noble gases by their trapping in its haze

Abstract

Titan's haze, formed by photolysis of C ₂H ₂, C ₂H ₄ and HCN, was found experimentally to trap Ar, Kr and Xe with efficiencies of 3.5 × 10 ^-4, 1.9 × 10 ^-3 and 6.5 × 10 ^-2 [noble gas atom]/[carbon atom] in the polymer, respectively. The rate of aerosol formation and settling down of 3 × 10 ^-13 kg m ^-2 s ^-1, as inferred from our experiments on CH ₄ photolysis in the far UV [Podolak, M., Bar-Nun, A., 1979. Icarus 39, 272-276], is sufficient to reduce the mixing ratios of ³⁶Ar and ⁴⁰Ar to their low values of (2.8 ± 0.3) × 10 ^-7 and (4.3 ± 0.1) × 10 ^-3, respectively, and those of Kr and Xe to below the detection limit of 10 ^-8.