Observations of Hydrocarbons in the Stratospheres of Jupiter and Saturn Using Celeste

We are using Celeste, an infrared (5-25 μm) high-resolution (ΔR/R ~103-104) cryogenic ground-based grating spectrometer, at the McMath-Pierce Telescope of the National Solar Observatory at Kitt Peak, and at the NASA InfraRed Telescope Facility on top of Mauna Kea, to observe hydrocarbon line emission spectral features originating from the stratospheres of the planets Jupiter and Saturn. These observations are being performed in support of the Composite InfraRed Spectrometer (CIRS) instrument aboard the Cassini spacecraft on its mission past Jupiter and currently orbiting Saturn. Over the past few years we have recorded several ν4 lines of CH4 (1228.5 cm-1), the ν5 R(5) line of C2H2 (743.3 cm-1) and the ν9 RQ0 branch of C2H6 (822.3 cm-1) for Jupiter and Saturn on several occasions. We also have additional observations of the H2 S(1) emission line (587.0 cm-1) and several ν9 C2H4 lines (949.5 cm-1) for Jupiter. From these observations we have been able to infer molecular abundances for the given species at the pressure levels where their contribution functions are maximum (~1-10 mbar) that help constraint current photochemical models for the stratospheres of the planets. In particular we have been able to construct maps in longitude and latitude for Jupiter from the C2H2 and C2H6 data that compare favorably with the CIRS measurements, opening the door for further ground-based synoptic observations that could reflect seasonal abundance/temperature changes in the atmosphere of the planet. The current status of the observing campaign and recent modeling results will be presented.