NASA's Juno Sees Fresh Lava Flows at Zal Patera

This black-and-white visible wavelength (450-1,100 nm) image of Io's surface was taken by the Stellar Reference Unit (SRU) aboard NASA's Juno spacecraft during a close flyby of the volcanic moon on Dec. 30, 2023.

The image was taken from a distance of about 932 miles (1,500 kilometers) over the night side of Io in a region dimly illuminated by Jupiter-shine. It is Juno's highest resolution image of Io, at about half- to three-quarters of a mile (895 to 1,230 meters) per pixel. The image covers the Zal Montes-Patera complex (the two mountains and large dark patera at the center of the image) and the western portion of the Tonatiuh eruptive center (at left edge of left image and top edge of right image). The left panel is the raw SRU image, and the right panel shows the image projected onto the surface of Io with north up.

The image reveals fresh new lava flows at Zal Patera (the large dark patera between the two mountains) with possible jets of sulfur dioxide gas at the flow fronts. The SRU's sensitivity at near-infrared wavelengths enabled detection of thermal emission signatures from multiple active lava breakouts in Zal Patera and at the base of South Zal Mons (the lower mountain in the image at right). An unprecedented elongated, curved emission feature is observed to the west of South Zal Mons and is suspected to be an active lava channel.

The image also captures the first high-resolution view of Tonatiuh's geomorphology. The SRU observes a fresh (dark) crenulated lava flow at Tonatiuh (left edge of left image and top edge of right image), showing that this volcano's flows are consistent with an insulated Promethean-style compound flow field. The lava flow is 98 by 11 miles (158 by 18 kilometers).

The SRU collects images of star fields to provide star positions used for attitude determination. Designed for low-light conditions, the camera has proved itself a valuable science tool, discovering shallow lightning in Jupiter's atmosphere, imaging the planet's enigmatic ring system, finding hints of recent surface activity on Europa, and now providing a view of Io's volcanoes in action.

More information about Juno is at https://www.nasa.gov/juno and https://missionjuno.swri.edu.