New Research Reveals Atmospheric Possibilities for TRAPPIST-1 b
Recent observations from the James Webb Space Telescope (JWST) have provided new insights into the atmospheric conditions of the exoplanet TRAPPIST-1 b. Data collected during the secondary eclipse at wavelengths of 12.8 and 15 microns indicates a notably bright dayside, suggesting a lack of atmosphere. This finding aligns with earlier one-dimensional atmospheric models that also pointed towards an absence of significant carbon dioxide-rich atmospheres.
As research continues, it becomes clear that only a limited range of potential atmospheric types have been thoroughly investigated thus far. The latest work includes a comprehensive thermal phase curve analysis of TRAPPIST-1 b at 15 microns, enabling scientists to delve deeper into the planet’s thermal structure. The team, led by Alice Maurel and Martin Turbet, focused on identifying atmospheric compositions that could generate emissions consistent with the secondary eclipse observations.
Utilizing both a one-dimensional radiative-convective model and a three-dimensional global climate model (GCM), the researchers simulated various atmospheric compositions and surface pressures. Their comparative analysis revealed several atmospheric families that are compatible with the observed eclipse data at a significance level of 2-sigma. Among these, some scenarios exhibited a flat phase curve, which could be dismissed based on current observations, while others maintained compatibility with the data, including thin nitrogen-carbon dioxide atmospheres and hazy carbon dioxide-rich atmospheres.
The researchers also highlighted critical three-dimensional effects that previous one-dimensional models could not predict, including atmospheric redistribution efficiency and potential atmospheric collapse. Their findings suggest that the existing observations of TRAPPIST-1 b are most consistent with an airless planet, although the possibility of a thin, CO2-poor residual atmosphere cannot be entirely ruled out.
The implications of this research are significant. It emphasizes the complexity of determining atmospheric conditions based on photometric data alone. As noted in the study, concluding the presence of an atmosphere from a solitary photometric measurement can be misleading. The research, comprising 26 pages and 24 figures, has been accepted for publication in the journal Astronomy and Astrophysics, underlining its contribution to the field of Earth and planetary astrophysics.
Scientists continue to explore the atmospheric dynamics of distant exoplanets, and findings like those from TRAPPIST-1 b serve as crucial steps in understanding planetary formation and habitability in the universe. The study is available on arXiv, with the submission dated September 2, 2025, under the identifier arXiv:2509.02120. Further details can be accessed via the provided DOI link.
