A planet orbiting a dim red star just 40 light-years away may be the most Earth-like world discovered so far. Scientists using the James Webb Space Telescope have identified signs that TRAPPIST-1e could host a nitrogen-rich atmosphere—one of the key ingredients for surface liquid water and, potentially, life.
While the data is still incomplete, early results show a promising deviation from the typical carbon dioxide-heavy environments seen on planets like Venus and Mars. This discovery marks one of the clearest advances yet in the search for habitable worlds beyond our solar system.
The planet in question, TRAPPIST-1e, belongs to a well-known system discovered in 2016 that captured scientific attention for hosting several rocky, Earth-sized planets. Located in the constellation Aquarius, the TRAPPIST-1 system is a compact planetary neighborhood orbiting an ultra-cool red dwarf star. Of its seven known exoplanets, a few—including TRAPPIST-1e—reside in the so-called habitable zone, the orbital sweet spot where temperatures could allow water to exist in liquid form.
This characteristic has made TRAPPIST-1 a focus of numerous observational campaigns over the past decade. But proximity to a red dwarf comes with challenges. These stars are prone to flares and high radiation, which can strip away planetary atmospheres. That’s why the latest data from JWST has raised such interest: TRAPPIST-1e seems to buck that trend.
Tentative Signs of a Stable, Nitrogen-Rich Atmosphere
TRAPPIST-1e’s atmosphere—or the potential for one—is at the heart of the new findings. A team of researchers led by Néstor Espinoza (Space Telescope Science Institute) and Natalie Allen (Johns Hopkins University) analyzed four planetary transits captured by the James Webb Space Telescope, searching for light filtered through a possible atmospheric layer. According to ScienceAlert, this complex process involved sifting through star-related interference and isolating spectral data tied specifically to the planet.
Initial results were inconclusive but suggestive. “We are seeing two possible explanations,” said astrophysicist Ryan MacDonald (University of St Andrews). “The most exciting possibility is that TRAPPIST-1e could have a so-called secondary atmosphere containing heavy gases like nitrogen.” Researchers also noted the lack of spectral features associated with thick carbon dioxide atmospheres, the kind common on Mars and Venus.
Instead, the data leaned toward a thinner atmosphere composed mostly of molecular nitrogen, possibly with trace amounts of carbon dioxide and methane—elements also present in Earth’s atmospheric makeup.
Proximity to a Red Dwarf Brings Challenges and Surprises
Red dwarf stars like TRAPPIST-1 are relatively cool and dim, which means their habitable zones lie much closer in than those around sun-like stars. That proximity raises a major concern: intense stellar flaring and radiation, known to erode or completely strip planetary atmospheres. Previous observations of TRAPPIST-1d, a neighboring planet in the same system, showed no signs of an atmosphere, possibly due to this very effect.
According to MIT astronomer Sara Seager, co-author on one of the research papers, “The evidence pointing away from Venus- and Mars-like atmospheres sharpens our focus on the scenarios still in play.” Her comment underlines the importance of distinguishing between planets that simply lie in the habitable zone and those that can actually retain the conditions for habitability.
TRAPPIST-1e’s slightly greater distance from its star may be providing just enough shielding to preserve some form of atmospheric envelope—an unexpected finding in a system where intense stellar activity is the norm.
Next Steps in the Search for Extraterrestrial Habitability
Although the data remains preliminary, the study represents the first attempt to identify specific atmospheric components on an Earth-sized exoplanet within a nearby star system. Interpreting the planetary spectra required careful correction for contamination caused by the red dwarf’s inherent variability, and even then, results were what researchers described as “frustratingly ambiguous.”
Yet, there’s momentum to build on. A second research team, led by Ana Glidden (MIT), has started interpreting the early spectroscopic data, laying the groundwork for future observations. These could confirm the presence of nitrogen and clarify whether TRAPPIST-1e truly hosts an atmosphere capable of supporting liquid water.
“We’re in a new age of exploration that’s very exciting to be a part of,” Glidden said. “It’s incredible to measure the details of starlight around Earth-sized planets 40 light-years away and learn what it might be like there, if life could be possible there.”