Webb Telescope Spies Io’s Volcanic Activity and Sulfurous Atmosphere
By Sarah Stanley, Eos/AGU.
Excerpt: Trapped in a gravitational push and pull between Jupiter and other Jovian moons, Io is constantly being stretched and compressed. Heat generated by these contortions has melted pockets of the moon’s interior so much that Io is our solar system’s most volcanically active body. The James Webb Space Telescope (JWST) recently opened up new opportunities to get to know Io. Using data from its Near Infrared Spectrograph—which sees wavelengths corresponding to different compositions and temperatures—de Pater et al. have made new discoveries about Io’s volcanoes and atmosphere. The researchers first looked at Io in November 2022 and found an extremely energetic volcanic eruption in the vicinity of the lava flow field Kanehekili Fluctus. These observations revealed, for the first time, that some volcanoes on Io emit an excited form of sulfur monoxide gas, confirming the team’s 2-decade-old hypothesis. JWST also detected an increase in thermal emissions at the massive lava lake in Loki Patera, generated by the lake’s thick, solid surface crust sinking into the molten lava beneath. Nine months later, in August 2023, ...lava flows from the 2022 Kanehekili region’s eruption had spread to cover more than 4,300 square kilometers—about 4 times the area they covered in 2022. At Loki Patera, a new crust had formed and cooled, in keeping with the lake’s behavior over the past few decades....