Ref - Atmospheric Reconnaissance of TRAPPIST-1 b with JWST/NIRISS: Evidence for Strong Stellar Contamination in the Transmission Spectra,
https://iopscience.iop.org/article/10.3847/2041-8213/acf7c4, 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.