JWST Unveils 3D View of Scorching Planet Environment

Astronomers have produced the primary three-dimensional map of a planet exterior our photo voltaic system, revealing distinct temperature areas, together with one so scorching that water vapor breaks aside. The findings seem in Nature Astronomy, revealed October 28, 2025.

Led by researchers on the University of Maryland and Cornell University, the examine charts temperatures throughout WASP-18b, a large gasoline large categorised as an “ultra-hot Jupiter” positioned 400 light-years from Earth. The workforce utilized a way often called 3D eclipse mapping, additionally known as spectroscopic eclipse mapping, marking the primary time this method has been used to construct a full 3D temperature map. The work expands on a 2D eclipse map the group launched in 2023 utilizing extremely delicate observations from NASA’s James Webb Space Telescope (JWST).

“This technique is really the only one that can probe all three dimensions at once: latitude, longitude and altitude,” stated the paper’s co-lead creator Megan Weiner Mansfield, an assistant professor of astronomy at UMD. “This gives us a higher level of detail than we’ve ever had to study these celestial bodies.”

With this strategy, scientists can start charting atmospheric variations throughout many exoplanets observable by JWST, a lot as ground-based telescopes as soon as documented Jupiter’s Great Red Spot and its banded clouds.

“Eclipse mapping allows us to image exoplanets that we can’t see directly, because their host stars are too bright,” stated the paper’s co-lead creator Ryan Challener, a postdoctoral affiliate in Cornell University’s Department of Astronomy. “With this telescope and this new technique, we can start to understand exoplanets along the same lines as our solar system neighbors.”

Spotting exoplanets is troublesome as a result of they’re sometimes far dimmer than their stars, usually contributing lower than 1% of the entire mild. Eclipse mapping measures tiny variations in that mild because the planet strikes behind its star, alternately hiding and revealing completely different areas. By tying these small brightness adjustments to particular places on the planet and analyzing them in a number of colours, scientists can reconstruct temperatures throughout latitude, longitude, and altitude.

WASP-18b is effectively suited to this check as a result of it has concerning the mass of 10 Jupiters, completes an orbit in solely 23 hours, and reaches temperatures close to 5,000 levels Fahrenheit. Those properties present a relatively sturdy sign for the brand new mapping technique.

The workforce’s earlier 2D map used a single coloration of sunshine. For the 3D model, they reanalyzed the identical JWST information from the Near-Infrared Imager and Slitless Spectrograph (NIRISS) throughout many wavelengths. Each coloration probes completely different layers of WASP-18b’s environment and corresponds to a particular temperature and altitude. Combining these layers yields an in depth three-dimensional temperature construction.

“If you build a map at a wavelength that water absorbs, you’ll see the water deck in the atmosphere, whereas a wavelength that water does not absorb will probe deeper,” Challener defined. “If you put those together, you can get a 3D map of the temperatures in this atmosphere.”

The 3D evaluation identifies spectroscopically distinct zones on the planet’s everlasting dayside, which at all times faces the star as a result of the planet is tidally locked. A round scorching spot sits the place the star’s mild strikes most instantly, and winds seem too weak to unfold that warmth effectively. A cooler ring encircles the new heart close to the limb of the planet. Measurements additionally present lowered water vapor inside the scorching spot in contrast with the planet’s common.

“We’ve seen this happen on a population level, where you can see a cooler planet that has water and then a hotter planet that doesn’t have water,” Weiner Mansfield defined. “But this is the first time we’ve seen this be broken across one planet instead. It’s one atmosphere, but we see cooler regions that have water and hotter regions where the water’s being broken apart. That had been predicted by theory, but it’s really exciting to actually see this with real observations.”

Additional JWST observations may sharpen the spatial element in future 3D eclipse maps. Weiner Mansfield famous that the strategy opens new alternatives to check many “hot Jupiters,” which quantity within the lots of among the many greater than 6,000 confirmed exoplanets. She additionally goals to use 3D eclipse mapping to smaller, rocky worlds past gasoline giants like WASP-18b.

“It’s very exciting to finally have the tools to see and map out the temperatures of a different planet in this much detail. It’s set us up to possibly use the technique on other types of exoplanets. For example, if a planet doesn’t have an atmosphere, we can still use the technique to map the temperature of the surface itself to possibly understand its composition,” Mansfield stated. “Although WASP-18b was more predictable, I believe we will have the chance to see things that we could never have expected before.”

This analysis was supported by the James Webb Space Telescope’s Transiting Exoplanet Community Early Release Science Program.