NASA's Juno spacecraft recently passed by Io on March 1, one of Jupiter's four largest moons, at a distance of 51,500 km (32,030 miles), reported first by Universe Today.
The latest images captured by Juno provide the closest view of Io, which is the most volcanic moon in our Solar System since the New Horizons mission flew by the Jupiter system in 2006 en route to Pluto.
Pizza-shaped Moon
Despite the time-lapse, the moon still appears as pizza-shaped. The surface of Io is diverse and colorful, resulting from its numerous volcanic activities. The moon's surface also has hundreds of vents and calderas that create various geological features.
The volcanic plumes and lava flow across the moon's surface and appear in a range of colors, such as red, yellow, orange, and black.
Some lava rivers extend for hundreds of kilometers. Juno has completed 49 orbits of Jupiter in its extended mission and is scheduled to investigate several other moons of Jupiter.
The recent Io flyby was the third of nine flybys of the volcanic moon in the next year, with the first taking place in December 2022.
The next flyby of Io is scheduled for February 3, 2024, and is expected to be closer, at a distance of 1,500 kilometers (930 miles).
Juno's mission to investigate the gas giant and its moons has already yielded significant scientific discoveries, and further observations of Io and other moons are likely to provide additional insights into the formation and evolution of our Solar System.
Reddening of Chors Patera
Jason Perry, a specialist in Io observation who has worked with the Cassini, Galileo, and HiRISE imaging teams, noted that his initial impressions of these images indicate some minor variations from the New Horizons photographs.
"Surface changes are pretty subtle but there are at least two. The first is a small flow from the eastern end of East Girru. This was a hotspot first seen by New Horizons in the middle of a mini outburst. Still active according to Juno JIRAM," Perry wrote in a tweet.
"The other is a reddening of Chors Patera. Reddish material on Io indicates the presence of S3-S4, short-chained sulfur that have to be refreshed regularly through active, high-temperature volcanism."
The Jovian InfraRed Auroral Mapper (JIRAM) has both an imager and a spectrometer, which share the same telescope. According to Jason Perry, a member of the Juno team, the JIRAM data shows a reddening of Chors Patera, a bowl-shaped volcanic crater on Io.
This red material indicates the presence of short-chained sulfur that requires regular refreshment through high-temperature volcanism.
Juno's next encounter with Io will occur during Perijove 51 on May 16, 2023, at a distance of 35,000 kilometers.
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