Mid-infrared spectra and images of Jupiter's auroral regions during perijoves 11 - 15

Energetic charged particles from the Jovianmagnetosphere penetrate the atmosphere in the polar regions and deposit their energy into the neutral atmosphere to pressures as deep as the 1-mbar level (or approximately 150 km above the 1 bar level). The resulting precipitation, ion drag and joule heating warms the neutral stratosphere and modifies the hydrocarbon chemistry (e.g. Sinclair et al., 2017a, Icarus 292, 182-207, Sinclair et al., 2018, Icarus 300, 305-326). This coupling of the neutral stratosphere and the magnetosphere can be sensed by the mid-infrared emission of stratospheric CH₄, C₂H₂, C₂H₄and further hydrocarbon species. Mid-infrared measurements of Jupiter's auroral regions were performed near-contemporaneously with perijoves (PJ) 11-15 in order to sense the atmosphere-magnetosphere coupling at stratospheric altitudes, a region poorly sampled by Juno's instrumentation. High-spatial resolution 7.8-μm images of Jupiter's stratospheric CH₄emission were measured by Subaru-COMICS (Kataza et al., 2000, Optical and IR Telescope Instrumentation and Detectors, 4008 1144-1152) on March 31-April 1^st(PJ12), May 24-25^th(PJ13). The morphology of CH₄auroral emission will be compared with Juno and HST measurements of the ultraviolet auroral emission to explore the correlation of high UV color ratios, inferred to be driven by lateral Pedersen currents, with heating of the neutrals. High-spectral resolution IRTF-TEXES (Lacy et al., 2002, PASP 114, 153-168) measurements of CH₄, C₂H₂, C₂H₄emission were acquired on February 9-12 (PJ11) and July 11-16 (PJ14). A retrieval analysis will be conducted to derive three-dimensional maps (altitude, latitude, longitude) of temperature and hydrocarbon abundances at Jupiter's high latitudes. New constraints on the vertical profile of CH₄in Jupiter's auroral region (Clark et al., 2018, under review) will be adopted in this analysis to explore the effects on retrieved parameters. Both datasets will be compared with measurements supporting previous perijoves and the approach phase of Juno to Jupiter to explore the longer-term variability of the auroral stratosphere.