Astronomers Created A 3D Map Of An Exoplanet We Can't See

The James Webb Space Telescope (JWST) helped astronomers to find and create a 2D model of an exoplanet in 2023. More recently, in 2025, that same exoplanet has gotten a revolutionary 3D mapping treatment, helping scientists to understand it as never before. It is a new technique that promises to open up an exciting future for space research.

Exoplanets are planets that exist outside of our solar system. This specific one is called WASP-18b and is 400 lightyears from Earth. Though exoplanets can be very difficult to see, the James Webb Space Telescope has helped with such discoveries. WASP-18b in particular is a gas giant with a 23-hour orbit, and its 5,000 degrees Fahrenheit temperature helped it be seen by the JWST.

Creating a 3D map of WASP-18b was a challenging effort that brought together a team of 36 researchers from institutions such as Cornell University, Arizona State University, the Austrian Academy of Sciences, the University of Montreal, and more. Their work was published in the Nature Astronomy journal in late 2025 under the title "Horizontal and vertical exoplanet thermal structure from a JWST spectroscopic eclipse map." Their process and findings can help us better understand what exists outside of our own solar system.

The power of the JWST was essential in this endeavor — this ultimate guide to the technology behind it and its capabilities gives a pretty good idea as to why. To turn the raw JWST data into a 3D map of this distant planet, the researchers used two different analysis techniques that look at how WASP-18b's light changed as it passed behind its star. One method, called Eigenspectra, analyzed each slice of color separately, providing more flexibility and allowing it to match the observed JWST signals much better. The second method, ThERESA, tries to fit everything at once using a full 3D model of the planet, which makes it more physically realistic but also harder to fine-tune, so it didn't capture some of the details seen in the data.

To overcome this, the Eigenspectra were the research team's focus with ThERESA being used mainly for confirmation. By watching how the planet's infrared light disappeared as it slipped behind its star, they reconstructed a three-dimensional picture of its atmosphere. The researchers grouped together regions of the planet based on similarly measured characteristics. They then used established atmospheric modeling tools to figure out how temperature changes with height and which chemicals are present in different parts of the planet.

The final result was a layered, region-by-region atmospheric profile, allowing scientists to reconstruct a 3D view of an exoplanet's atmosphere. The map revealed two distinct regions, with a hotter one facing the star it orbited and a cooler ring around the planet's edge.

The researchers refer to this technique as 3D eclipse mapping or as spectroscopic eclipse mapping. By combining the JWST and this technique, the researchers are hopeful that more exoplanets can be seen more clearly, as the James Webb's discoveries continue to challenge what we know about the universe.

As this technique could open up understanding more and more exoplanets, the research team sees this as an opportunity to understand these planets as a whole and how they individually vary. There are currently about 6,000 known exoplanets, so it is quite exciting to think about the possibility of 3D eclipse mapping being used on each of them to build a more thorough picture.

Looking to the future, the team already sees some improvements that can be made to the technique. With further observations of WASP-18b using the James Webb Space Telescope, the data can be further refined and expanded to create an even better 3D map. As the JWST makes new research possible, we can eagerly wait and see what future 3D mapping reveals about our universe.