The Jovian aurorae are hundreds of times brighter than those seen on Earth, says a team of astronomers by University of Leicester’s Dr. Jonathan Nichols.
These observations of Jupiter’s aurorae were captured with Webb’s Near-InfraRed Camera (NIRCam) on December 25, 2023. Image credit: NASA / ESA / CSA / STScI / Ricardo Hueso, UPV / Imke de Pater, UC Berkeley / Thierry Fouchet, Observatory of Paris / Leigh Fletcher, University of Leicester / Michael H. Wong, UC Berkeley / Joseph DePasquale, STScI / J. Nichols, University of Leicester / M. Zamani, ESA & Webb.
The aurorae are created when high-energy particles enter a planet’s atmosphere near its magnetic poles and collide with atoms of gas.
Not only are the aurorae on Jupiter huge in size, they are also hundreds of times more energetic than aurorae on Earth.
Here, aurorae are caused by solar storms — when charged particles rain down on the upper atmosphere, excite gases and cause them to glow colors of red, green and purple.
Meanwhile, Jupiter has an additional source for its aurorae — the strong magnetic field of the gas giant grabs charged particles from its surroundings.
This includes not only the charged particles within the solar wind but also the particles thrown into space by its volcanic moon Io.
Io’s volcanoes spew particles that, remarkably, escape the moon’s gravity and orbit Jupiter.
A barrage of charged particles unleashed by the Sun during solar storms also reaches the planet.
Jupiter’s large and powerful magnetic field captures charged particles and accelerates them to tremendous speeds.
These speedy particles slam into the planet’s atmosphere at high energies, which excites the gas and causes it to glow.
Now, the unique capabilities of the NASA/ESA/CSA James Webb Space Telescope are providing new insights into the Jovian aurorae.
The telescope’s sensitivity allows astronomers to increase the shutter speed in order to capture fast-varying auroral features.
The new data were captured with Webb’s Near-InfraRed Camera (NIRCam) on Christmas Day 2023.
“What a Christmas present it was – it just blew me away!” Dr. Nichols said.
“We wanted to see how quickly the aurorae change, expecting it to fade in and out ponderously, perhaps over a quarter of an hour or so.”
“Instead we observed the whole auroral region fizzing and popping with light, sometimes varying by the second.”
The astronomers found that the emission from the trihydrogen ion, known as H3+, is far more variable than previously believed.
The observations will help develop scientists’ understanding of how Jupiter’s upper atmosphere is heated and cooled.
The authors also uncovered some unexplained observations in their data.
“What made these observations even more special is that we also took pictures simultaneously in the ultraviolet with the NASA/ESA Hubble Space Telescope,” Dr. Nichols said.
“Bizarrely, the brightest light observed by Webb had no real counterpart in Hubble’s pictures. This has left us scratching our heads.”
“In order to cause the combination of brightness seen by both Webb and Hubble, we need to have an apparently impossible combination of high quantities of very low energy particles hitting the atmosphere — like a tempest of drizzle! We still don’t understand how this happens.”
The study was published in the journal Nature Communications.
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J.D. Nichols et al. 2025. Dynamic infrared aurora on Jupiter. Nat Commun 16, 3907; doi: 10.1038/s41467-025-58984-z
