Observations of weather and climate in giant planet upper atmospheres

Dr. James O'Donoghue
ISAS/JAXA Dept. of Solar System Sciences

At Jupiter and Saturn, magnetosphere-ionosphere coupling gives rise to intense auroral emissions and enormous energy deposition in the magnetic polar regions. At Jupiter, we found that temperatures decrease steadily from the auroral polar regions to the equator, indicating that the aurora act as a planet-wide heating source. On top of this, during a period of enhanced activity in Jupiter's auroral region, a high-temperature planetary-scale-sized structure was also observed to traveling toward the equator from the poles. This presentation reports on the particulars of this feature, including how it appears to be propagating away from the auroral region (as determined by estimates of the features' velocity at several longitudes) and its implications for global energy circulation at Jupiter and other planets. In general, these are our first glimpses into both climate and weather in Jupiter's upper atmosphere. I will also discuss our plans to follow-up on this study with new Keck data recorded in FY2022. At Saturn, the rings dominate the non-auroral conditions around the planet via a mechanism called 'ring rain'. Electrically charged material rains onto the planet, leaving a signal in the upper atmospheric emissions measured from ground-based telescopes like Keck. I will discuss how we will examine new JWST data, which has exquisite sensitivity, to learn more about the ring rain phenomenon, and show how it is important for determining the erosion rate, hence the lifetime, of Saturn's rings.

Via Zoom