[P-PS01] Outer Solar System Exploration Today, and Tomorrow

[PPS01-11] Investigations of Giant Planet Upper Atmospheres: Past, Present and Future

★Invited Papers

*James O Donoghue¹, Luke Moore², Chihiro Tao⁴, Go Murakami¹, Tom Stallard³, Henrik Melin³, Hajime Kita⁵ (1.JAXA Institute of Space and Astronautical Science, 2.Boston University, 3.University of Leicester, 4.National Institute Of Information And Communications Technology (NICT), 5.Tohoku University)

Keywords:Giant Planets, Jupiter, Upper atmosphere

The upper atmospheres of Giant Planets mark the transition region between weather layers and outer space. These are tenuous regions, making them highly sensitive to physical processes acting both from above and below. In this presentation, I will detail how we have investigated the upper atmospheres of the giant planets using telescopes and space probes, for example large ground-based observatories such as the Keck telescope, space-based observatories such as the Hubble Space Telescope and orbiters such as the Cassini spacecraft. I will discuss a study I led recently which involves observations of a planetary-scale 'heat wave' emanating from Jupiter's auroral region. This study used ground-based maps of Jupiter's upper atmosphere temperatures obtained via the emissions of the major upper-atmospheric ion, H₃⁺, one of the main probes of conditions in giant planet upper atmospheres. The heat wave appears to follow a solar wind compression of the Jovian magnetosphere, which is supported by a solar wind model and Juno spacecraft in-situ WAVES data. I will report on the particulars of this feature, including the features' velocity at several longitudes, and its implications for global energy circulation at Jupiter and other planets. At the end, I will then discuss the future direction of research in general for giant planet upper atmospheres, including the new possibilities afforded by the latest and next generation of observatories and space missions, such as the James Webb Space Telescope, European Extremely Large Telescope, and Jupiter Icy Moons Explorer (JUICE).