Detectability of biosignatures in anoxic atmospheres with the James Webb Space Telescope: a TRAPPIST-1e case study
The James Webb Space Telescope (JWST) may be capable of finding biogenic gases in the atmospheres of habitable exoplanets around low-mass stars. Considerable attention has been given to the detectability of biogenic oxygen, which could be found using an ozone proxy, but ozone detection with JWST wil...
| Main Authors: | , , , |
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| Format: | Journal article |
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American Astronomical Society
2018
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| _version_ | 1797059610849312768 |
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| author | Krissansen-Totton, J Garland, R Irwin, P Catling, D |
| author_facet | Krissansen-Totton, J Garland, R Irwin, P Catling, D |
| author_sort | Krissansen-Totton, J |
| collection | OXFORD |
| description | The James Webb Space Telescope (JWST) may be capable of finding biogenic gases in the atmospheres of habitable exoplanets around low-mass stars. Considerable attention has been given to the detectability of biogenic oxygen, which could be found using an ozone proxy, but ozone detection with JWST will be extremely challenging, even for the most favorable targets. Here, we investigate the detectability of biosignatures in anoxic atmospheres analogous to those that likely existed on the early Earth. Arguably, such anoxic biosignatures could be more prevalent than oxygen biosignatures if life exists elsewhere. Specifically, we simulate JWST retrievals of TRAPPIST-1e to determine whether the methane plus carbon dioxide disequilibrium biosignature pair is detectable in transit transmission. We find that ~10 transits using the Near InfraRed Spectrograph prism instrument may be sufficient to detect carbon dioxide and constrain methane abundances sufficiently well to rule out known, nonbiological CH4 production scenarios to ~90% confidence. Furthermore, it might be possible to put an upper limit on carbon monoxide abundances that would help rule out nonbiological methane-production scenarios, assuming the surface biosphere would efficiently draw down atmospheric CO. Our results are relatively insensitive to high-altitude clouds and instrument noise floor assumptions, although stellar heterogeneity and variability may present challenges. |
| first_indexed | 2024-03-06T20:06:44Z |
| format | Journal article |
| id | oxford-uuid:29246a9d-53dc-4518-9ec9-270e4f403ff9 |
| institution | University of Oxford |
| last_indexed | 2024-03-06T20:06:44Z |
| publishDate | 2018 |
| publisher | American Astronomical Society |
| record_format | dspace |
| spelling | oxford-uuid:29246a9d-53dc-4518-9ec9-270e4f403ff92022-03-26T12:17:21ZDetectability of biosignatures in anoxic atmospheres with the James Webb Space Telescope: a TRAPPIST-1e case studyJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:29246a9d-53dc-4518-9ec9-270e4f403ff9Symplectic Elements at OxfordAmerican Astronomical Society2018Krissansen-Totton, JGarland, RIrwin, PCatling, DThe James Webb Space Telescope (JWST) may be capable of finding biogenic gases in the atmospheres of habitable exoplanets around low-mass stars. Considerable attention has been given to the detectability of biogenic oxygen, which could be found using an ozone proxy, but ozone detection with JWST will be extremely challenging, even for the most favorable targets. Here, we investigate the detectability of biosignatures in anoxic atmospheres analogous to those that likely existed on the early Earth. Arguably, such anoxic biosignatures could be more prevalent than oxygen biosignatures if life exists elsewhere. Specifically, we simulate JWST retrievals of TRAPPIST-1e to determine whether the methane plus carbon dioxide disequilibrium biosignature pair is detectable in transit transmission. We find that ~10 transits using the Near InfraRed Spectrograph prism instrument may be sufficient to detect carbon dioxide and constrain methane abundances sufficiently well to rule out known, nonbiological CH4 production scenarios to ~90% confidence. Furthermore, it might be possible to put an upper limit on carbon monoxide abundances that would help rule out nonbiological methane-production scenarios, assuming the surface biosphere would efficiently draw down atmospheric CO. Our results are relatively insensitive to high-altitude clouds and instrument noise floor assumptions, although stellar heterogeneity and variability may present challenges. |
| spellingShingle | Krissansen-Totton, J Garland, R Irwin, P Catling, D Detectability of biosignatures in anoxic atmospheres with the James Webb Space Telescope: a TRAPPIST-1e case study |
| title | Detectability of biosignatures in anoxic atmospheres with the James Webb Space Telescope: a TRAPPIST-1e case study |
| title_full | Detectability of biosignatures in anoxic atmospheres with the James Webb Space Telescope: a TRAPPIST-1e case study |
| title_fullStr | Detectability of biosignatures in anoxic atmospheres with the James Webb Space Telescope: a TRAPPIST-1e case study |
| title_full_unstemmed | Detectability of biosignatures in anoxic atmospheres with the James Webb Space Telescope: a TRAPPIST-1e case study |
| title_short | Detectability of biosignatures in anoxic atmospheres with the James Webb Space Telescope: a TRAPPIST-1e case study |
| title_sort | detectability of biosignatures in anoxic atmospheres with the james webb space telescope a trappist 1e case study |
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