These bright (hot) “heat rings” are a common phenomenon and indicate active lava lakes. Jupiter Infrared Auroral Mapper (JIRAM) instrument aboard NASA’s Juno spacecraft.
Visible, infrared and temperature maps of Loki Patera and Dazhbog Patera. Image courtesy of Mura others., doi: 10.1038/s43247-024-01486-5.
Io is the innermost of Jupiter’s four Galilean moons and the fourth largest moon in the solar system.
Apart from Earth, it is the only known place in the solar system with volcanoes that spew hot lava like Earth’s.
Io has over 400 active volcanoes, which are caused by tidal heating due to gravity from Jupiter and the other Jovian moons.
There are many theories about the types of volcanic eruptions on the Moon, but little data to support them.
NASA’s Juno spacecraft will pass by Io in May and October 2023, coming within about 35,000 km (21,700 miles) and 13,000 km (8,100 miles), respectively.
Among Juno’s observational instruments giving a closer look at the fascinating moon was JIRAM.
JIRAM is designed to capture infrared light emitted from deep within Jupiter, studying the weather layer 50 to 70 km (30 to 45 miles) below Jupiter’s cloud tops.
However, during Juno’s long mission, the mission team also used the instrument to study moons such as Io, Europa, Ganymede, and Callisto.
JIRAM images of Io showed the presence of bright rings surrounding the base of many hotspots.
“The high spatial resolution of JIRAM’s infrared images, combined with Juno’s favorable position during the flyby, revealed that Io’s entire surface is covered by lava lakes in caldera-like formations,” said Dr Alessandro Mura, a researcher at the National Institute for Astrophysics in Rome and Juno co-investigator.
“In the area of Io’s surface where we have the most complete data, we estimate that about 3% of it is covered by one of these lava lakes. Calderas are large depressions that form when volcanoes erupt and collapse.”
This image taken by NASA’s Galileo spacecraft shows volcanic eruptions on Io. Image credit: NASA/JPL/University of Arizona.
JIRAM’s flyby data will not only reveal Io’s rich lava reserves, but also provide a glimpse into what’s going on beneath the surface.
Infrared images of some of Io’s lava lakes show a thin circular layer of lava at the boundary between the central crust that covers most of the lake and the lake walls.
The lack of lava flows above or beyond the lake’s edge suggests melt circulation, demonstrating a balance between the melt erupted into the lava lake and that circulated back into the subsurface system.
“We now know what the most frequent volcanic activity on Io is: huge lava lakes with magma rising and falling,” Dr Mura said.
“The lava crust collapses against the lake wall, forming the typical lava rings seen in Hawaiian lava lakes.”
“The walls are thought to be hundreds of metres high, which explains why magma is not typically observed spilling out of pateras – bowl-shaped formations formed by volcanic activity – and moving across the lunar surface.”
JIRAM data suggests that the surfaces of these Io hotspots consist largely of a rocky crust that periodically moves up and down as one continuous surface due to central upwelling of magma.
In this hypothesis, friction between the crust and the lake wall would prevent it from sliding, causing it to deform and eventually break away, exposing the lava just below the surface.
Another hypothesis, which remains valid, is that magma wells up in the middle of the lake, spreading out and forming a crust that sinks along the lake’s edge, exposing the lava.
“We’re just beginning to look at the results from JIRAM’s approach to Io in December 2023 and February 2024,” said Juno principal investigator Dr. Scott Bolton from the Southwest Research Institute.
“These observations reveal fascinating new information about Io’s volcanic activity.”
“When we combine these new results with Juno’s long-term campaign to monitor and map Io’s never-before-seen north and south pole volcanoes, JIRAM is poised to become one of the most valuable tools for learning about the workings of this tormented world.”
of Investigation result Published in a journal Nature Communications.
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A. Mura others2024. Io’s hot ring as seen by Juno/JIRAM. Community Global Environment 5, 340; doi: 10.1038/s43247-024-01486-5
Source: www.sci.news
