The strength and evolution of stratospheric-auroral processes on Jupiter, as observed by IRTF-TEXES

Auroral processes on Jupiter are evident over a large range of wavelengths. Juno's JIRAM (Jovian Infrared Auroral Mapper) and UVS (Ultraviolet Spectrometer) instruments will observe Jupiter's auroral emission at near-infrared and ultraviolet wavelengths, highlighting the precipitation of charged particles in Jupiter's thermosphere. These observations can then be related to measurements by Juno's MAG (magnetometer), JADE (Jovian Auroral Distributions Experiment) and JEDI instruments (Jovian Energetic Particle Detector Instrument), which will prove a powerful tool in studying the interaction of Jupiter's atmosphere with the external magnetosphere. However, Juno's scientific payload does not include a mid-infrared instrument (5 - 15 microns) capable of sounding Jupiter's stratosphere in which a significant amount of energy associated with auroral processes is deposited. As demonstrated by Sinclair et al., 2016a (under review) from a retrieval analysis of Voyager-IRIS (Infrared Interferometer Spectrometer) observations in 1979, Cassini-CIRS (Composite Infrared Spectrometer) observations in 2001 and IRTF-TEXES (Texas Echelon Cross Echelle Spectrograph) observations in 2014, temperatures in the northern auroral region at 70°N, 180°W are elevated by up to approximately 20 K and 35 K at the 1-mbar and 10-ubar levels respectively, in comparison to quiescent longitudes (see attached Figure). However, the physical mechanisms responsible for modifications of the thermal structure and composition of the stratosphere in auroral regions are still not well understood. We hope to better understand the processes driving the auroral-stratosphere interaction on Jupiter by characterizing whether and by what magnitude the thermal structure and composition of the stratosphere evolve at Jupiter's high latitudes. In April 2016, we obtained IRTF-TEXES measurements of Jupiter's high-latitudes under similar conditions to those obtained in December 2014. We will perform a retrieval analysis to determine the vertical profiles of temperature, C2H2, C2H4 and C2H6. Results will be compared with those in December 2014 to determine the 3D evolution of the thermal structure and composition in proximity to the auroral regions: the attached Figure shows preliminary temperature results.