Variability of ethane on Jupiter

Abundances and spatial distributions of ethane in Jupiter's stratosphere were obtained from ultrahigh-resolution ( Λ/ΔΛ ∼ 10 ⁶) spectra of individual C ₂H ₆ emission lines in the ν₉ band near 12 μm. The accuracy of the retrieved C ₂H ₆ mole fractions was evaluated in the context of varying stratospheric temperature profiles and C ₂H ₆ altitude distributions. A twofold uncertainty in the accuracy of the obtained abundances is possible. A mean equatorial value for the C ₂H ₆ mole fraction of 2.8 ± 0.6 × 10 ^t-6 was retrieved. Significant variability in the ethane line emission and retrieved mole fractions was found near the footprint of Io's flux tube and within the auroral regions. An increase in the ethane emission and abundance is obtained near the south polar region, relative to equatorial and northern latitudes. A significant decrease in ethane emission and abundance was observed in April 1983 near the known "hot spot" at 180° long (System III, 1965) and 60°N lat, where enhanced CH ₄ and C ₂H ₂ emission was previously observed. We suggest that these observed phenomena are caused by a modification of local stratospheric chemistry, possibly by higher order effects of charged particles precipitating along magnetic field lines.