11.03.2026Meet a Scientist: Dr. Gabriele Cugno

[UZH Space]: You are one of a few people within Switzerland who work with data from the James
Webb Space Telescope (JWST), one of the most powerful space-based telescopes
ever built. How does a researcher actually gain access to JWST data, and what is
the process of applying for observing time?

[Dr. Gabriele Cugno]: Getting access to JWST data is a long and intense process. Astronomers submit detailed proposals explaining what we want to observe, why the science matters and is relevant to better understand the Universe and our place in it, and why JWST is uniquely suited for it. Then, panels of international experts review and rank the proposals, and only a small fraction (~1 every 13 or so) are approved, since demand far exceeds the available observing time. If selected, the proposal is reviewed by instrument experts, who help us adjusting the tiniest of details to make the observations exceptional and the program enters the observing queue. We don’t operate the telescope ourselves, but the data are delivered to us once the observations are completed. And from there the funny and exciting detective work begins!

Many people see the stunning images produced by JWST, but your work goes much deeper than the pictures. How do you transform raw telescope data into scientific discoveries?

The beautiful images are really just the tip of the iceberg. Behind the scenes, teams at Space Telescope Science Institute performed extraordinary calibration work in the first phases of the mission, and continue to update and improve data reduction tools. This allows to correct instrumental effects and transform raw signals into reliable scientific data. At this point, our job is to dig deeper using specialized analysis techniques. I developed a custom post-processing pipeline for JWST’s Mid-Infrared Instrument Medium Resolution Spectrograph that reveals extremely faint signals buried in the overwhelming glare of their host stars. This is like trying to spot a headlamp next to a lighthouse in a wavelength range where these techniques have never been employed. In my specific case, by carefully modelling and removing the starlight in young systems, we can reveal the subtle fingerprints of dust and gas disks around newborn planets and study how planetary and moon systems take shape.

Your research looks for moon-forming disks around distant planets. For people who are not astronomers: what exactly is a moon-forming disk, and why is it so exciting to detect one around an exoplanet?

A moon-forming disk, or a circumplanetary disk, is a disk of gas and dust surrounding a young planet during its formation, similar to the disk that once encircled Jupiter when its famous Galilean moons were born. The material inside them can assemble into moons, just as planets form around stars. Detecting one around a distant exoplanet is exciting because it lets us witness, in real time, the processes that shaped some components of our own Solar System. Circumplanetary disks also regulate how young giant planets accrete material, setting the thermal starting conditions that influence their atmospheres for millions of years. In short, by studying them we learn not only how moons form, but also how giant planets themselves come to life.

One of the methods you use is called "molecular mapping“. How does this method work, and what can it reveal about the environments where planets and moons form?

“Molecular mapping” is a technique that lets us identify specific molecules in regions that are otherwise impossible to see directly. Instruments onboard JWST are able to take images and for each pixel split the light into thousands of wavelengths, creating something that can be compared to a chemical barcode. Each molecule leaves a unique pattern of emission features, and by searching similarities between these patterns with theoretical models we can detect gases even when their signals are extremely faint. The condition is that these same molecules do not appear anywhere else in the image. This allows us to probe the composition, temperature, and abundances of the material surrounding young planets.

If we observe moon-forming disks around exoplanets, what can that tell us about the formation of moons in our own Solar System? Can we draw conclusions about how common systems like our own Solar System might be?

Indeed, moon-forming disks around distant planets are natural laboratories where we can test the origins of the Solar System. This is exactly the direction I believe the field should move toward, but it’s challenging. We need to observe many more circumplanetary disks before we can draw robust conclusions, which is why I’m leading several JWST programs targeting the full sample of known young planets with such disks. At the moment, however, we can only study planets that orbit far from their stars, unlike the compact architecture of our Solar System. A major leap will come with the Extremely Large Telescope, expected at the beginning of the next decade, which will allow us to probe moon-forming regions at Solar System scales. Even then, new challenges appear, since Earth’s atmosphere makes some key measurements much harder than from space, but I am optimistic we will find a way to overcome these limitations.

Looking ahead, what discoveries about planets, moons, or planetary systems are you personally most excited that JWST might help us uncover in the coming years?

What excites me most is that James Webb Space Telescope is finally allowing us to directly image and study mature planetary systems that resemble scaled versions of our own Solar System. Its incredible sensitivity lets us image planets as small as Saturn, and possibly even lighter ones, which was simply out of reach before. That’s a huge step toward understanding how typical (or unusual) our Solar System really is. Naturally, I’m especially excited about circumplanetary disks, which I see as one of the next great frontiers in astronomy. The strong interest from the community and major investments by observatories show how transformative this field could become. But if history has taught us anything, especially from Hubble Space Telescope, it’s that the biggest discoveries are often the ones we were not able to predict. Once we start exploring new territory, surprises are guaranteed. The next decade of JWST science is going to be a fantastic ride!

Interview: Dr. Jean-Noël Mettler (UZH Space) with Dr. Gabriele Cugno (Department of Astrophysics UZH)

Find out more about Dr. Gabriele Cugno: https://gcugno.github.io 

Links to his research:
https://iopscience.iop.org/article/10.3847/2041-8213/ad3cbc
https://science.nasa.gov/missions/webb/nasas-webb-telescope-studies-moon-forming-disk-around-massive-planet/