JWST discovers new options in Saturn’s ambiance

This set of nonetheless photographs from an animation reveals the darkish, bead-like options embedded in vivid halos that the house telescope captured.
Credit: NASA/ESA/CSA/Stallard et al 2025

A research of Saturn’s atmospheric construction utilizing information from the James Webb Space Telescope (JWST) has revealed advanced and mysterious options unseen earlier than on any planet. The outcomes had been introduced final week by Tom Stallard of Northumbria University, on the EPSC-DPS2025 Joint Meeting in Helsinki and was revealed in Geophysical Research Letters.

“This opportunity to use JWST was the first time we have ever been able to make such detailed near-infrared observations of Saturn’s aurora and upper atmosphere. The results came as a complete surprise,” mentioned Stallard in a press release.

“We anticipated seeing emissions in broad bands at the various levels. Instead, we’ve seen fine-scaled patterns of beads and stars that, despite being separated by huge distances in altitude, may somehow be interconnected — and may also be linked to the famous hexagon deeper in Saturn’s clouds. These features were completely unexpected and, at present, are completely unexplained.”

The worldwide workforce of researchers, comprising 23 scientists from establishments throughout England, the United States, and France, made the discoveries throughout a steady 10-hour commentary interval on November 29, 2024, as JWST tracked Saturn’s rotation.

The workforce targeted on detecting infrared emissions by a positively charged molecular type of hydrogen, H3⁺, which performs a key position in reactions in Saturn’s ambiance. Because it does, it will possibly present helpful insights into the chemical and bodily processes at work. JWST’s Near Infrared Spectrograph allowed the workforce to look at H₃⁺ ions from the ionosphere, 680 miles (1,100 kilometers) above what scientists think about Saturn’s floor. The telescope and its devices additionally concurrently monitored methane molecules within the underlying stratosphere, at an altitude of 370 miles (600 km).

In the electrically charged plasma of the ionosphere, the workforce noticed a collection of darkish, bead-like options embedded in vivid auroral halos. These constructions remained steady over hours however appeared to float slowly over longer durations.

Approximately 310 miles (500 km) decrease, in Saturn’s stratosphere, the workforce found an uneven star-shaped characteristic. This uncommon construction prolonged out from Saturn’s north pole. Only 4 of the star’s six arms had been seen, with two mysteriously lacking, making a lopsided sample.

“Saturn’s upper atmosphere has proven incredibly difficult to study with missions and telescope facilities to date due to the extremely weak emissions from this region,” mentioned Stallard. “JWST’s incredible sensitivity has revolutionized our ability to observe these atmospheric layers, revealing structures that are completely unlike anything we’ve seen before on any planet.”

The workforce mapped the precise places of the options and located that they overlaid the identical area of Saturn at totally different ranges, with the star’s arms showing to emanate from positions immediately above the factors of the storm-cloud-level hexagon. This means that the processes which can be driving the patterns could affect a column stretching proper by means of Saturn’s ambiance.

“We think that the dark beads may result from complex interactions between Saturn’s magnetosphere and its rotating atmosphere, potentially providing new insights into the energy exchange that drives Saturn’s aurora. The asymmetric star pattern suggests previously unknown atmospheric processes operating in Saturn’s stratosphere, possibly linked to the hexagonal storm pattern observed deeper in Saturn’s atmosphere,” mentioned Stallard.

“Tantalizingly, the darkest beads in the ionosphere appear to line up with the strongest star-arm in the stratosphere, but it’s not clear at this point whether they are actually linked or whether it’s just a coincidence.”

While each options may have vital implications for understanding atmospheric dynamics on fuel big planets, extra work is required to supply explanations for the underlying causes.

The workforce hopes that extra time could also be granted in future to hold out follow-up observations of Saturn with JWST to additional discover the options. With the planet at its equinox (which means the rings now tilt at a shallow angle from our viewpoint), which happens roughly each 15 Earth years, the constructions could change dramatically as Saturn’s orientation to the Sun shifts and the northern hemisphere strikes into autumn.

“Since neither atmospheric layer can be observed using ground-based telescopes, the need for JWST follow-up observations during this key time of seasonal change on Saturn is pressing,” Stallard added.