Trend Analysis for Atmospheric Hydrocarbon Partitioning Using Continuous Thermodynamics

The partitioning of atmospheric hydrocarbons into vapor and condensed phases when the species count is large is considered using the formalism of continuous thermodynamics. The vapor saturation pressures and condensate species distribution are parameterized using the species normal boiling temperatures. Qualitative trends in activity coefficient values and phase equilibrium behavior that are relevant to the outer planets and Titan are discussed in terms of a much simplified perspective on these aspects of partitioning. The trends found are generally consistent with those from other published atmospheric model results.