Elemental composition, solubility, and optical properties of Titan's organic haze

Abstract It is found that solid organic material produced by electrical discharge in a simulated Titan atmosphere (10% CH4, 90% N2) has an elemental composition corresponding to C11H11N2. Immersion in liquid ethane followed by filtration indicates that the organic solid is insoluble in ethane and, it is supposed, in methane. An upper limit is placed on the soluble fraction of 0.03% by mass. When the mixing ratio of CH4 is varied from 10 to 100% it is found that the organic solid produced becomes progressively darker in the ultraviolet and violet (0.2–0.4 μm) compared to the visible and near-infrared (0.4–0.75 μm). The optical properties are variable by more than a factor of 2 between experiments. Sedimentation of solid haze material on the surface of Titan represents a comparatively small loss for carbon. For nitrogen, however, the loss rate of 108 N atoms cm−2s−1 in haze material is greater than 10% of the total production of N in the upper atmosphere.

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