The Spectroscopic Analysis of Jupiter’s Great Red Spot using JWST/MIRI

<p dir="ltr">This thesis uses mid-infrared data from the James Webb Space Telescope Mid- InfraRed Instrument (JWST/MIRI), obtained in July and August 2022 to infer the thermal, chemical and dynamical structure of Jupiter’s Great Red Spot (GRS). This survey took place alongside a suite of visual and infrared observations from Hubble, JWST/NIRCam, VLT/VISIR and amateur observers. Due to the brightness of the target and the novelty of the observatory, bespoke calibration solutions were derived and published that have subsequently been integrated into the standard calibration pipeline for all users of JWST/MIRI. JWST/MIRI spectroscopy was inverted using the NEMESIS software to derive the 3D temperature, composition and aerosol structure of the GRS. The retrieved stratospheric temperature structure revealed a series of hot-spots above the GRS. These could be the consequence of GRS-induced wave activity. In the troposphere, the temperatures were used to derive the thermal wind structure of the GRS vortex. These winds were only consistent with the wind field determined by JWST/NIRCam at 240 mbar if the altitude of the Hubble-derived winds were located around 1,200 mbar, considerably deeper than previously assumed. No enhancement in ammonia was found within the GRS but a link between elevated aerosol and phosphine abundances was observed within this region. North-south asymmetries were observed in the retrieved temperature, ammonia, phosphine and aerosol structure, consistent with the GRS tilting in the north-south direction. Finally, a small storm was captured north-west of the GRS that displayed an excess in retrieved phosphine abundance, suggestive of vigorous convection. Despite this, no ammonia ice was detected in this region. I led the campaign to calibrate, model and analyse the JWST data. Work from this thesis is published in Argyriou et al. (2023), Fletcher et al. (2023b), Harkett et al. (2024), and King et al. (2023).</p>