Searching for an Atmosphere

“The key question for TRAPPIST-1e is simple: if it has an atmosphere, it could be habitable,” said Ranjan, an assistant professor at LPL. “But first, we need to determine whether an atmosphere exists at all.”

Figure 1. Distant Exoplanet Shows Signs of Potential Life-Building Molecule, Scientists Urge Caution.

To investigate, researchers used the James Webb Space Telescope’s Near-Infrared Spectrograph (NIRSpec) to observe TRAPPIST-1e as it transited its host star. During a transit, starlight passes through any planetary atmosphere, allowing astronomers to detect absorbed wavelengths and infer the presence of specific chemicals. The more transits observed, the clearer the atmospheric signature becomes. Figure 1 shows Distant Exoplanet Shows Signs of Potential Life-Building Molecule, Scientists Urge Caution.

Analysis of four transits revealed hints of methane. However, interpreting the results requires caution because TRAPPIST-1e orbits an M dwarf—an ultracool red dwarf about one-tenth the size of the Sun. Unlike the Sun, this dim, cool star could influence observed signals, raising the question: is the methane from the planet or the star itself?

To investigate, Ranjan’s team ran simulations of TRAPPIST-1e with methane-rich atmospheres, evaluating the likelihood of each scenario. In the most probable case, the planet resembled Titan, Saturn’s methane-rich moon. Yet even this scenario remained highly unlikely.

“Based on our latest analysis, the previously reported hint of an atmosphere is more likely just noise from the host star,” Ranjan said. “This doesn’t rule out the possibility that TRAPPIST-1e has an atmosphere—we simply need more data.”

Advancing Tools and Techniques

Ranjan noted that while the James Webb Space Telescope is transforming exoplanet science, it wasn’t originally designed to study small, Earth-like worlds.

“It was built long before we even knew these planets existed, so it’s remarkable that it can study them at all,” he explained. “Only a handful of Earth-sized planets are within reach for any detailed atmospheric analysis.”

New insights may come from NASA’s upcoming Pandora mission, scheduled for launch in early 2026. Led by Daniel Apai, professor of astronomy and planetary sciences at the University of Arizona’s Steward Observatory, Pandora is a small satellite designed to study exoplanet atmospheres and their host stars. It will observe stars hosting potentially habitable planets before, during, and after transits.

Meanwhile, researchers are developing new observational strategies and analytical techniques. One promising approach is the dual transit method, which observes TRAPPIST-1e and the system’s innermost, airless planet, TRAPPIST-1b, crossing the star simultaneously.

“These observations will help us separate stellar activity from any atmospheric signals the planet may have,” Ranjan said.

Source: SciTECHDaily

Cite this article:

Priyadharshini S (2025), Possible Building Block of Life Spotted on Distant Exoplanet, but Scientists Advise Caution, AnaTechMaz, pp.634