This TRAPPIST-1 exoplanet seems to have no atmosphere — the truth may hide in its star, James Webb Space Telescope reveals

Ref - Atmospheric Reconnaissance of TRAPPIST-1 b with JWST/NIRISS: Evidence for Strong Stellar Contamination in the Transmission Spectra,, 22-Sep-2023.

"...Accounting for stellar contamination, our analyses confidently reject clear H2-rich atmospheres for TRAPPIST-1 b. However, the current SOSS observations cannot confirm whether TRAPPIST-1 b is a bare rock or if it has a thin and/or high-mean-molecular-mass atmosphere, although the latter scenario has been rejected for certain compositions by secondary eclipse observations with JWST/MIRI (Greene et al. 2023; Ih et al. 2023). As TRAPPIST-1 b is the planet in the system most likely to have lost its atmosphere (Krissansen-Totton 2023), a lack of atmosphere would not suggest that the outer planets are bare rocks and thus should not discourage future observations of the TRAPPIST-1 system. Assessing the presence of an atmosphere on the habitable-zone and outer TRAPPIST-1 planets is currently only possible with transmission spectroscopy. Given the lack of stellar model fidelity, additional theoretical work (e.g., Witzke et al. 2022; Rackham et al. 2023) and/or observations of the host star (e.g., Berardo et al. 2023) are necessary to provide better constraints on the contribution of stellar contamination to future transmission spectra.”

My note, TRAPPIST-1 b may indeed be a *bare rock* and if the other TRAPPIST-1 system exoplanets are similar (little or no atmospheres), that would pose challenges for astrobiology.
Some of the other TRAPPIST-1 system exoplanets likely have no atmospheres too as previously reported.

“TRAPPIST-1 c likely has an incredibly thin atmosphere, or no atmosphere at all. New data from NASA's James Webb Space Telescope (JWST) shows that the atmosphere of a rocky exoplanet in the TRAPPIST-1 system is either non-existent or incredibly thin, making it unfavorable for hosting life as we know it..."Our results are consistent with the planet being a bare rock with no atmosphere, or the planet having a really thin CO2 atmosphere (thinner than on Earth or even Mars) with no clouds," James Webb Space Telescope spies on rocky TRAPPIST-1 exoplanet, finds bad news for life,


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