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Arxiv: The Thermal Structure and Composition of Jupiter's Great Red Spot From JWST/MIRI Published: 10/2/2024 1:54:49 PM Updated: 10/2/2024 1:54:49 PM

Paper abstract: Jupiter's Great Red Spot (GRS) was mapped by the James Webb Space Telescope(JWST)/Mid-Infrared Instrument (4.9-27.9 micron) in July and August 2022. Theseobservations took place alongside a suite of visual and infrared observationsfrom; Hubble, JWST/NIRCam, Very Large Telescope/VISIR and amateur observerswhich provided both spatial and temporal context across the jovian disc. Thestratospheric temperature structure retrieved using the NEMESIS softwarerevealed a series of hot-spots above the GRS. These could be the consequence ofGRS-induced wave activity. In the troposphere, the temperature structure wasused to derive the thermal wind structure of the GRS vortex. These winds wereonly consistent with the independently determined wind field by JWST/NIRCam at240 mbar if the altitude of the Hubble-derived winds were located around 1,200mbar, considerably deeper than previously assumed. No enhancement in ammoniawas found within the GRS but a link between elevated aerosol and phosphineabundances was observed within this region. North-south asymmetries wereobserved in the retrieved temperature, ammonia, phosphine and aerosolstructure, consistent with the GRS tilting in the north-south direction.Finally, a small storm was captured north-west of the GRS that displayed aconsiderable excess in retrieved phosphine abundance, suggestive of vigorousconvection. Despite this, no ammonia ice was detected in this region. Thenovelty of JWST required us to develop custom-made software to resolvechallenges in calibration of the data. This involved the derivation of the"FLT-5" wavelength calibration solution that has subsequently been integratedinto the standard calibration pipeline.