Webb Telescope Reveals Explosive Aurora Activity on Jupiter.

 

NASA’s James Webb Space Telescope captured vivid new details of Jupiter’s auroras on Dec. 25, 2023, using its NIRCam at 3.36 microns. The observations revealed that H₃⁺ emissions—produced by high-energy electrons striking molecular hydrogen—are far more variable than previously thought.

NASA’s James Webb Space Telescope has captured extraordinary new details of Jupiter’s auroras, revealing these massive light shows to be far more dynamic and powerful than ever observed. The auroras on our solar system’s largest planet are hundreds of times brighter than those seen on Earth.

Auroras occur when high-energy particles enter a planet’s atmosphere near its magnetic poles and collide with gas atoms or molecules, creating glowing displays. On Earth, these are the Northern and Southern Lights, driven by solar storms that energize atmospheric gases into brilliant shades of red, green, and purple.

But Jupiter’s auroras are in a league of their own. Not only are they colossal in scale, but they also carry vastly more energy. In addition to solar wind particles, Jupiter’s powerful magnetic field captures charged material ejected by its volcanic moon Io. These particles are accelerated to high speeds and slam into Jupiter’s upper atmosphere, causing it to glow intensely.

Webb’s NIRCam captured Jupiter’s auroras at 3.36 microns on Dec. 25, 2023, revealing unexpectedly variable H₃⁺ emissions caused by high-energy electrons striking molecular hydrogen. A reference image of Jupiter shows the aurora’s location.

Now, Webb’s cutting-edge sensitivity has allowed astronomers to observe these auroras in unprecedented detail. Using the Near-Infrared Camera (NIRCam), a team led by Jonathan Nichols of the University of Leicester captured fast-changing auroral features on December 25, 2023.

“What a Christmas present it was – it just blew me away!” said Nichols.

“We expected the auroras to fade in and out slowly, maybe over 15 minutes. Instead, the whole region was fizzing and popping with light, changing by the second.”

The researchers focused on emissions from the trihydrogen cation (H₃⁺), a molecule formed in auroral activity. They discovered that this emission varies much more quickly than previously known, offering new clues into how Jupiter’s upper atmosphere is heated and cooled.

Adding to the mystery, simultaneous ultraviolet images taken by NASA’s Hubble Space Telescope did not match Webb’s near-infrared data.

“Bizarrely, the brightest light seen by Webb had no counterpart in Hubble’s images,” Nichols noted.

“To explain this, we’d need high amounts of low-energy particles hitting the atmosphere – something we didn’t think was possible. We’re still trying to understand it.”

The team plans to follow up with more Webb observations, and compare them with data from NASA’s Juno spacecraft to better understand the unusual emissions and what they reveal about Jupiter’s space environment.

These groundbreaking findings were published today in Nature Communications.

The James Webb Space Telescope, the world’s premier space science observatory, is an international mission led by NASA with the European Space Agency (ESA) and the Canadian Space Agency (CSA). Webb continues to reshape our understanding of the universe, from the secrets of our solar system to the farthest reaches of space.