Enhanced C2H2 Absorption Within Jupiter's Southern Auroral Oval From Juno UVS Observations.

Reflected sunlight observations from the Ultraviolet Spectrograph (UVS) on the Juno spacecraft were used to study the distribution of acetylene (C2H2) at Jupiter's south pole. We find that the shape of the C2H2 absorption feature varies significantly across the polar region, and this can be used to infer spatial variability in the C2H2 abundance. There is a localized region of enhanced C2H2 absorption which coincides with the location of Jupiter's southern polar aurora; the C2H2 abundance poleward of the auroral oval is a factor of 3 higher than adjacent quiescent, non‐auroral longitudes. This builds on previous infrared studies, which found enhanced C2H2 abundances within the northern auroral oval. This suggests that Jupiter's upper‐atmosphere chemistry is being strongly influenced by the influx of charged auroral particles and demonstrates the necessity of developing ion‐neutral photochemical models of Jupiter's polar regions. Plain Language Summary: The Ultraviolet Spectrograph on the Juno mission to Jupiter measures ultraviolet sunlight that is reflected from the planet's upper atmosphere and these observations can be used to measure the abundances of different gases in the stratosphere. In this paper, we study the spatial distribution of the molecule acetylene at Jupiter's south pole. We find that there is a significant increase in the acetylene abundance at the location of Jupiter's southern aurora. This suggests that the charged particles that travel along magnetic field lines toward Jupiter's poles and produce bright auroral emission also have a strong influence on the chemistry of Jupiter's upper atmosphere. Key Points: Ultraviolet reflected sunlight observations from Juno Ultraviolet Spectrograph were used to study the distribution of C2H2 at Jupiter's south poleFrom the changes in the spectral shape, we infer enhanced C2H2 absorption within the southern auroral ovalJupiter's atmospheric chemistry at the poles is strongly influenced by the influx of charged auroral particles [ABSTRACT FROM AUTHOR]