Observations of CH 4, C 2H 6, and C 2H 2in the Stratosphere of Jupiter

We have performed high-resolution spectral observations at mid-infrared wavelengths of CH4(8.14 μm), C2H6(12.16 μm), and C2H2(13.45 μm) on Jupiter. These emission features probe the stratosphere of the planet and provide information on the carbon-based photochemical processes taking place in that region of the atmosphere. The observations were performed using our cryogenic echelle spectrometer CELESTE, in conjunction with the McMath-Pierce 1.5-m solar telescope between November 1994 and February 1995. We used the methane observations to derive the temperature profile of the jovian atmosphere in the 1-10 mbar region of the stratosphere. This profile was then used in conjunction with height-dependent mixing ratios of each hydrocarbon to determine global abundances for ethane and acetylene. The resulting mixing ratios are 3.9+1.9-1.3× 10-6for C2H6(5 mbar pressure level), and 2.3 ± 0.5 × 10-8for C2H2(8 mbar pressure level), where the quoted uncertainties are derived from model variations in the temperature profile which match the methane observation uncertainties.