Variability of Ethane on Jupiter

Abundances and spatial distributions of ethane in Jupiter's stratosphere were obtained from ultrahigh-resolution (Λ/ΔΛ~106) spectra of individual C2H6 emission lines in the ν9 band near 12 μm. The accuracy of the retrieved C2H6 mole fractions was evaluated in the context of varying stratospheric temperature profiles and C2H6 altitude distributions. A twofold uncertainty in the accuracy of the obtained abundances is possible. A mean equatorial value for the C2H6 mole fraction of 2.8 ± 0.6 × 10t-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 CH4 and C2H2 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.