Article

Impact of Clouds and Hazes on the Simulated JWST Transmission Spectra of Habitable Zone Planets in the TRAPPIST-1 System

Thomas J. FauchezGSFC Sellers Exoplanet Environments Collaboration, USAMartin TurbetLaboratoire de Méteorologie Dynamique, IPSL, Sorbonne Universités, UPMC Univ Paris 06, CNRS, 4 Place Jussieu, F-75005 Paris, FranceGeronimo L. VillanuevaGSFC Sellers Exoplanet Environments Collaboration, USAEric WolfLaboratory for Atmospheric and Space Physics, Department of Atmospheric and Oceanic Sciences, University of Colorado Boulder, Boulder, CO, USAGiada ArneyGSFC Sellers Exoplanet Environments Collaboration, USARavi KopparapuGSFC Sellers Exoplanet Environments Collaboration, USAAndrew LincowskiDepartment of Astronomy and Astrobiology Program, University of Washington, Box 351580, Seattle, WA 98195, USAAvi MandellGSFC Sellers Exoplanet Environments Collaboration, USAJulien de WitDepartment of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USADaria PidhorodetskaNASA Goddard Space Flight Center, Greenbelt, MD, USAShawn Domagal‐GoldmanGSFC Sellers Exoplanet Environments Collaboration, USAKevin B. StevensonJohns Hopkins APL, 1100 Johns Hopkins Rd., Laurel, MD 20723, USA

2019en

ABI

Abstract

Abstract The TRAPPIST-1 system, consisting of an ultracool host star having seven known Earth-sized planets, will be a prime target for atmospheric characterization with the James Webb Space Telescope ( JWST ). However, the detectability of atmospheric molecular species may be severely impacted by the presence of clouds and/or hazes. In this work, we perform 3D general circulation model (GCM) simulations with the LMD-G model supplemented by 1D photochemistry simulations at the terminator with the Atmos model to simulate several possible atmospheres for TRAPPIST-1e, 1f, and 1g: (1) modern Earth, (2) Archean Earth, and (3) CO 2 -rich atmospheres. The JWST synthetic transit spectra were computed using the GSFC Planetary Spectrum Generator. We find that the TRAPPIST-1e, 1f, and 1g atmospheres, with clouds and/or hazes, could be detected using JWST ’s NIRSpec Prism from the CO 2 absorption line at 4.3 μ m in less than 15 transits at 3 σ or less than 35 transits at 5 σ . However, our analysis suggests that other gases would require hundreds (or thousands) of transits to be detectable. We also find that H 2 O, mostly confined in the lower atmosphere, is very challenging to detect for these planets or similar systems if the planets’ atmospheres are not in a moist greenhouse state. This result demonstrates that the use of GCMs, self-consistently taking into account the effect of clouds and subsaturation, is crucial to evaluate the detectability of atmospheric molecules of interest, as well as for interpreting future detections in a more global (and thus robust and relevant) approach.

Identifiers

DOI: 10.3847/1538-4357/ab5862

Citations and references

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