Journal
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Volume 515, Issue 2, Pages 1982-1992Publisher
OXFORD UNIV PRESS
DOI: 10.1093/mnras/stac1869
Keywords
opacity; atmospheric effects; occultations; planets and satellites: atmospheres
Categories
Funding
- Trottier Excellence Grant
- Technologies for Exo-Planetary Science (TEPS) Undergraduate Fellowship
- Institute for Research on Exoplanets (iREx)
- McGill Space Institute (MSI)
- McGill Exoplanet Characterization Alliance (MEChA)
Ask authors/readers for more resources
The James Webb Space Telescope (JWST) will provide an opportunity to investigate the atmospheres of potentially habitable planets. This study explores the impact of aerosols and clouds on JWST's ability to observe deeper layers of exoplanetary atmospheres. The research finds that JWST would not be able to detect Earth-like stratospheric clouds in the TRAPPIST-1 system, but it would be able to detect them in the habitable zone of a white dwarf after only four transits.
The James Webb Space Telescope (JWST) will provide an opportunity to investigate the atmospheres of potentially habitable planets. Aerosols significantly mute molecular features in transit spectra because they prevent light from probing the deeper layers of the atmosphere. Earth occasionally has stratospheric/high tropospheric clouds at 15-20 km that could substantially limit the observable depth of the underlying atmosphere. We use solar occultations of Earth's atmosphere to create synthetic JWST transit spectra of Earth analogues orbiting dwarf stars. Unlike previous investigations, we consider both clear and cloudy sightlines from the SCISAT satellite. We find that the maximum difference in effective thickness of the atmosphere between a clear and globally cloudy atmosphere is 8.5 km at 2.28 mu m, with a resolution of 0.02 mu m. After incorporating the effects of refraction and Pandexo's noise modelling, we find that JWST would not be able to detect Earth-like stratospheric clouds if an exo-Earth was present in the TRAPPIST-1 system, as the cloud spectrum differs from the clear spectrum by a maximum of 10 ppm. These stratospheric clouds are also not robustly detected by TauREx when performing spectral retrieval for a cloudy TRAPPIST-1 planet. However, if an Earth-sized planet were to orbit in a white dwarf's habitable zone, then we predict that JWST's NIRSpec would be able to detect its stratospheric clouds after only four transits. We conclude that stratospheric clouds would not impede JWST transit spectroscopy or the detection of biosignatures for Earth-like atmospheres.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available