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Scientists are using NASA’s James Webb Space Telescope (JWST) to uncover the mysteries of the exoplanet TRAPPIST-1 e, one of seven Earth-sized worlds orbiting the red dwarf star TRAPPIST-1. Early results are painting intriguing possibilities about what its atmosphere and surface might be like — and whether it could support liquid water. These findings bring us a step closer to answering one of humanity’s biggest questions: Are we alone in the universe?
Why TRAPPIST-1 e is special.
Among the seven planets in the TRAPPIST-1 system, planet e stands out. It orbits at a distance from its star where temperatures may allow water to exist on the surface. However, this is only possible if the planet has an atmosphere. Without one, it would be a barren rock like Mercury.
Using Webb’s powerful NIRSpec (Near-Infrared Spectrograph) instrument, astronomers observed TRAPPIST-1 e as it transited its star. During these events, starlight filters through the planet’s potential atmosphere. By studying tiny dips in the spectrum of that light, scientists can identify the chemical fingerprints of gases present around the planet.
First results: No primary atmosphere.
After analyzing four planetary transits, researchers believe TRAPPIST-1 e no longer has its primary hydrogen-helium atmosphere. This makes sense because red dwarfs like TRAPPIST-1 emit strong flares that can strip light atmospheres away.
But all hope is not lost. Many planets, including Earth, later form secondary atmospheres made of heavier gases like carbon dioxide, nitrogen, and water vapor. Whether TRAPPIST-1 e developed such an atmosphere remains one of the most exciting open questions.
Fewer possibilities, but hope remains.
The data suggests that TRAPPIST-1 e is unlikely to have an atmosphere dominated by carbon dioxide, unlike Venus or Mars. Still, a moderate greenhouse effect could exist, keeping the planet warm enough to host liquid water.
Researchers theorize that if water exists, it may be:
- spread across a global ocean, or
- trapped on the sunlit side of the tidally locked planet, surrounded by ice.
Since TRAPPIST-1 planets always show the same face to their star (like the Moon does to Earth), one side could be perpetually lit while the other stays in darkness.
Innovative methods for deeper insights.
To sharpen results, Webb’s team is conducting 15 more observations. In a clever strategy, they are observing TRAPPIST-1 b and e transits back-to-back. Because planet b likely has no atmosphere, its signals can help scientists separate out noise caused by the star itself. Any additional signals seen during planet e’s transit could then be confidently linked to its atmosphere.
This method will provide one of the clearest windows yet into the habitability of Earth-sized exoplanets.
A new age of cosmic exploration.
“We are still in the early stages of learning what kind of amazing science we can do with Webb,” said Ana Glidden of MIT’s Kavli Institute. “It’s incredible to measure starlight around planets 40 light-years away and ask if life could be possible there. We’re in a new age of exploration.”
These observations were made by the DREAMS (Deep Reconnaissance of Exoplanet Atmospheres using Multi-instrument Spectroscopy) collaboration, part of the JWST Telescope Scientist Team.
The James Webb Space Telescope is the world’s most advanced space science observatory, operated by NASA, with partners ESA and CSA. Webb continues to explore the origins of our universe, exoplanets, and the search for life beyond Earth.