Astronomers Disappointed as Trappist-1 d Exoplanet Lacks Earthlike Atmosphere

In the ongoing search for signs of life beyond Earth, astronomers have faced a setback in their examination of the Trappist-1 planetary system. A new study published on August 15, 2025, in The Astrophysical Journal has found that the third planet in the system, known as Trappist-1 d, does not appear to have an Earthlike atmosphere.

Researchers had previously identified the Trappist-1 system as a promising candidate for hosting potentially habitable exoplanets. The system, located about 40 light-years from Earth, consists of seven rocky planets orbiting a cool red dwarf star. However, the latest findings suggest that these types of stars may be too volatile to support the kind of atmosphere necessary for life as we know it.

The study's lead author, Caroline Piaulet-Ghorayeb, a postdoctoral researcher at the University of Chicago, explains that the starlight passing through Trappist-1 d's atmosphere did not show the presence of essential atmospheric molecules like water or carbon dioxide. This lack of an Earthlike atmosphere has dimmed astronomers' hopes for finding life on the planet.

Despite the disappointing results, Piaulet-Ghorayeb and her team have not completely ruled out the possibility of an atmosphere on Trappist-1 d. They suggest that alternative observation methods may still yield clues about the planet's atmospheric composition. However, the researchers acknowledge that the search for habitable exoplanets may need to shift focus to planets orbiting brighter stars, which may be more conducive to supporting life.

Astronomer Jacob Bean, who advises Piaulet-Ghorayeb but was not involved in the study, emphasizes the importance of continuing the search for extraterrestrial life, even in the face of setbacks. "If we go look, sometimes we come up disappointed," he says. "But if we hadn't looked, we wouldn't know. And it's always better to know."