Effect of Methane Mixing Ratio on the Lightning Chemistry of Titan by.

Titan, the largest satellite of Saturn, is one of the smallest planetary bodies with a dense atmosphere. Its nitrogen atmosphere contains methane at various mixing ratios depending on the altitude. The presence of methane clouds and rain suggest the possibility of electrical activity in the lower atmosphere. Voyager 1 did not detected lightning in Titan's atmosphere. Here we examine the chemical effects of lightning in various Titan's simulated atmosphere composed of CH₄ in N₂ at various mixing ratios. Lightning discharges were simulated in the laboratory by a hot and dense plasma generated by a high power Nd-YAG laser, and the final products were separated and detected by GC-FTIR-MS. A total of 24 compounds that include saturated, unsaturated and aromatic hydrocarbons and nitriles were detected. We have estimated the freeze out temperatures of HCN and C₂H₂ in the lightning channel taking into account the experimental [HCN]/[H₂C₂] ratios as a function of methane.