Understanding Jupiter’s polar Atmosphere & the Fate of the AeRosols (JAFAR)

Jupiter’s polar stratosphere exhibits unique chemical and dynamical processes that shape its atmospheric composition and structure. Hydrocarbon observations from multiple instruments (e.g., Voyager/IRIS, Cassini/CIRS, IRTF/TEXES, Juno/UVS, and JWST/MIRI) reveal abundance enhancements and strong latitudinal variations of C2 hydrocarbon species within the auroral regions. These enhancements are attributed to the influence of auroral energy deposition and possibly enhanced vertical mixing. IRTF/TEXES and JWST/MIRI observations also provide new constraints on the vertical structure of the polar atmosphere, suggesting that the methane homopause is located at higher altitudes in auroral regions than at lower latitudes. In addition, some observations indicate that Jupiter’s previously known aerosol layer is situated at higher altitudes in the polar regions (above about 20 mbar) compared to lower latitudes (around about 50 mbar). Magnetosphere–ionosphere–thermosphere coupling in Jupiter’s polar regions generates ionospheric winds with velocities of several km/s, which may propagate downward to the 0.1 mbar level, where neutral winds appear to be co-located with those measured at higher altitudes. Jupiter’s polar atmosphere thus constitutes a highly complex system in which magnetospheric forcing is strongly coupled with chemistry and dynamics from the ionosphere down to the tropopause. Understanding the distribution of hydrocarbons at high latitudes, and the extent to which they control the atmospheric radiative balance, is crucial for constraining upper-atmospheric dynamics. In this contribution, we provide a general overview of the physical and chemical processes governing Jupiter’s polar regions and present preliminary results from the JAFAR project, designed to investigate Jupiter’s polar atmosphere and the fate of aerosols, in preparation for the JUICE arrival in 2031.