Detectability of Biosignatures in Anoxic Atmospheres with the James Webb Space Telescope: A TRAPPIST-1e Case Study
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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 CH 4 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.
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Determining what the Archean atmosphere was made of and the influence of life could help distinguish biogenic gases in exoplanet atmospheres and find life elsewhere.
“So, determining what the Archean atmosphere was made of, and the influence of life, could help us distinguish biogenic gases in exoplanet atmospheres and so find life elsewhere (2, 250).”
From The Archean atmosphere (2020) · cites this paper as [250]
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Cites
Foreman-Mackey, D., Hogg, D. W., Lang, D., & Goodman, J. (2013) · Publications of the Astronomical Society of the Pacific · doi:10.1086/670067 · Cited by 13,362 · see citing works
The HITRAN 2008 molecular spectroscopic database
Rothman, L. S., Gordon, I. E., Barbe, A., Benner, D. C., Bernath, P. F., Birk, M., Boudon, V., Brown, L. R., Campargue, A., Champion, J. P., et al. (2009) · Journal of Quantitative Spectroscopy and Radiative Transfer · doi:10.1016/j.jqsrt.2009.02.013 · Cited by 3,339 · see citing works
MultiNest: an efficient and robust Bayesian inference tool for cosmology and particle physics
Feroz, F., Hobson, M., & Bridges, M. (2009) · Monthly Notices of the Royal Astronomical Society · doi:10.1111/j.1365-2966.2009.14548.x · Cited by 2,979 · see citing works
Terrestrial Gross Carbon Dioxide Uptake: Global Distribution and Covariation with Climate
Beer, C., Reichstein, M., Tomelleri, E., Ciais, P., Jung, M., Carvalhais, N., Rödenbeck, C., Arain, M. A., Baldocchi, D., Bonan, G. B., et al. (2010) · Science · doi:10.1126/science.1184984 · Cited by 2,841 · see citing works
corner.py: Scatterplot matrices in Python
Foreman-Mackey, D. T. (2016) · The Journal of Open Source Software · doi:10.21105/joss.00024 · Cited by 2,183 · see citing works
Soil microorganisms as controllers of atmospheric trace gases (H2, CO, CH4, OCS, N2O, and NO)
Conrad, R. (1996) · Microbiological Reviews · doi:10.1128/mr.60.4.609-640.1996 · Cited by 1,764 · see citing works
Feroz, F., & Hobson, M. (2008) · Monthly Notices of the Royal Astronomical Society · doi:10.1111/j.1365-2966.2007.12353.x · Cited by 1,679 · see citing works
Büchner, J., Georgakakis, A. E., Nandra, K., Hsu, L.-T., Rangel, C., Brightman, M., Merloni, A., Salvato, M., Donley, J. L., & Kocevski, D. D. (2014) · Astronomy and Astrophysics · doi:10.1051/0004-6361/201322971 · Cited by 1,654 · see citing works
Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
Gillon, M., Triaud, A. H. M. J., Demory, B.-O., Jehin, E., Agol, E., Deck, K. M., Lederer, S. M., de Wit, J., Burdanov, A., Ingalls, J. G., et al. (2017) · Nature · doi:10.1038/nature21360 · Cited by 1,555 · cited 1× · see citing works
“Barstow & Irwin (2016) applied these calculations specifically to the TRAPPIST-1 system (Gillon et al. 2017) and found that for modern-Earth-like atmospheres 30–60 transits would be necessary to reliably detect Earth-like O3 levels on 1b, 1c, and 1d.”
MultiNest: an efficient and robust Bayesian inference tool for cosmology and particle physicsPreprint
Feroz, F., Hobson, M., & Bridges, M. (2013) · Cited by 1,299 · see citing works
Lacis, A. A., & Oinas, V. (1991) · Journal of Geophysical Research: Atmospheres · doi:10.1029/90jd01945 · Cited by 1,051 · see citing works
The physiology and habitat of the last universal common ancestor
Weiss, M. C., Sousa, F. L., Mrnjavac, N., Neukirchen, S., Roettger, M., Nelson-Sathi, S., & Martin, W. F. (2016) · Nature Microbiology · doi:10.1038/nmicrobiol.2016.116 · Cited by 1,049 · see citing works
Atmospheric Radiation: Theoretical Basis
Goody, R. M., & Yung, Y. L. (1989) · Cited by 809 · see citing works
del Giorgio, P. A., & Duarte, C. M. (2002) · Nature · doi:10.1038/nature01165 · Cited by 597 · see citing works
The NEMESIS planetary atmosphere radiative transfer and retrieval tool
Irwin, P. G. J., Teanby, N. A., de Kok, R., Fletcher, L. N., Howett, C. J. A., Tsang, C. C. C., Wilson, C. F., Calcutt, S. B., Nixon, C. A., & Parrish, P. D. (2008) · Journal of Quantitative Spectroscopy and Radiative Transfer · doi:10.1016/j.jqsrt.2007.11.006 · Cited by 536 · see citing works
Self-citationBiosignatures from Earth-Like Planets Around M Dwarfs
Segura, A., Kasting, J. F., Meadows, V., Cohen, M., Scalo, J., Crisp, D., Butler, R. A. H., & Tinetti, G. (2005) · Astrobiology · doi:10.1089/ast.2005.5.706 · Cited by 524 · see citing works
Benneke, B., & Seager, S. (2012) · The Astrophysical Journal · doi:10.1088/0004-637x/753/2/100 · Cited by 430 · see citing works
Rackham, B. V., Apai, D., & Giampapa, M. S. (2018) · The Astrophysical Journal · doi:10.3847/1538-4357/aaa08c · Cited by 421 · see citing works
Climatic consequences of very high carbon dioxide levels in the earth’s early atmosphere
Kasting, J. F., & Ackerman, T. P. (1986) · Science · doi:10.1126/science.11539665 · Cited by 391 · see citing works
CHARACTERIZING TRANSITING EXOPLANET ATMOSPHERES WITH JWST
Greene, T. P., Line, M. R., Montero, C., Fortney, J. J., Lustig-Yaeger, J., & Luther, K. (2016) · The Astrophysical Journal · doi:10.3847/0004-637x/817/1/17 · Cited by 385 · see citing works
Ozone Concentrations and Ultraviolet Fluxes on Earth-Like Planets Around Other Stars
Segura, A., Krelove, K., Kasting, J. F., Sommerlatt, D., Meadows, V., Crisp, D., Cohen, M., & Mlawer, E. (2003) · Astrobiology · doi:10.1089/153110703322736024 · Cited by 379 · see citing works
How Earth's atmosphere evolved to an oxic state: A status report
Catling, D. C., & Claire, M. W. (2005) · Earth and Planetary Science Letters · doi:10.1016/j.epsl.2005.06.013 · Cited by 376 · see citing works
Self-citationTRANSITS OF EARTH-LIKE PLANETS
Kaltenegger, L., & Traub, W. A. (2009) · The Astrophysical Journal · doi:10.1088/0004-637x/698/1/519 · Cited by 353 · see citing works
PandExo: A Community Tool for Transiting Exoplanet Science withJWST&HST
Batalha, N. E., Mandell, A. M., Pontoppidan, K. M., et al. (2017) · Publications of the Astronomical Society of the Pacific · doi:10.1088/1538-3873/aa65b0 · Cited by 329 · see citing works
The cyanobacterial genome core and the origin of photosynthesis
Mulkidjanian, A. Y., Koonin, E. V., Makarova, K. S., Mekhedov, S. L., Sorokin, A. V., Wolf, Y. I., Dufresne, A., Partensky, F., Burd, H., Kaznadzey, D., et al. (2006) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.0605709103 · Cited by 325 · see citing works
A coupled atmosphere–ecosystem model of the early Archean Earth
KHARECHA, P., KASTING, J., & SIEFERT, J. (2005) · Geobiology · doi:10.1111/j.1472-4669.2005.00049.x · Cited by 321 · see citing works
ZAHNLE, K., CLAIRE, M., & CATLING, D. (2006) · Geobiology · doi:10.1111/j.1472-4669.2006.00085.x · Cited by 315 · see citing works
Self-citationCHARACTERIZING TRANSITING EXOPLANET ATMOSPHERES WITH JWST
Greene, T. P., Line, M. R., Montero, C., Fortney, J. J., Lustig‐Yaeger, J., & Luther, K. (2016) · eScholarship (California Digital Library) · Cited by 308 · see citing works
UV shielding of NH3and O2by organic hazes in the Archean atmosphere
Pavlov, A. A., Brown, L. L., & Kasting, J. F. (2001) · Journal of Geophysical Research Atmospheres · doi:10.1029/2000je001448 · Cited by 279 · see citing works
Zahnle, K. J. (1986) · Journal of Geophysical Research: Atmospheres · doi:10.1029/jd091id02p02819 · Cited by 276 · see citing works
The nature of the TRAPPIST-1 exoplanets.
Grimm, S., Demory, B., Gillon, M., Dorn, C., Agol, E., Burdanov, A., Delrez, L., Sestovic, M., Triaud, A., Turbet, M., et al. (2018) · Astronomy and Astrophysics · doi:10.1051/0004-6361/201732233 · Cited by 257 · see citing works
The cyanobacteria : molecular biology, genomics, and evolution
Herrero, A., & Flores, E. (2008) · Caister Academic Press eBooks · Cited by 252 · see citing works
Deeg, H. J., & Belmonte, J. (2018) · Springer eBooks · doi:10.1007/978-3-319-55333-7 · Cited by 249 · see citing works
Observing the Atmospheres of Known Temperate Earth-sized Planets with JWST
Morley, C., Kreidberg, L., Rustamkulov, Z., Robinson, T., & Fortney, J. (2017) · The Astrophysical Journal · doi:10.3847/1538-4357/aa927b · Cited by 244 · see citing works
Deming, D., Seager, S., Winn, J., Miller-Ricci, E., Clampin, M., Lindler, D., Greene, T., Charbonneau, D., Laughlin, G., Ricker, G., et al. (2009) · Publications of the Astronomical Society of the Pacific · doi:10.1086/605913 · Cited by 233 · see citing works
Exoplanet Biosignatures: A Framework for Their Assessment
Catling, D. C., Krissansen-Totton, J., Kiang, N. Y., Crisp, D., Robinson, T. D., DasSarma, S., Rushby, A. J., Del Genio, A., Bains, W., & Domagal-Goldman, S. (2018) · Astrobiology · doi:10.1089/ast.2017.1737 · Cited by 225 · see citing works
Self-citationAssessing the Habitability of the TRAPPIST-1 System Using a 3D Climate Model
Wolf, E. T. (2017) · The Astrophysical Journal Letters · doi:10.3847/2041-8213/aa693a · Cited by 209 · see citing works
Modeling climate diversity, tidal dynamics and the fate of volatiles on TRAPPIST-1 planets
Turbet, M., Bolmont, É., Leconte, J., Forget, F., Selsis, F., Tobie, G., Caldas, A., Naar, J., & Gillon, M. (2018) · Astronomy and Astrophysics · doi:10.1051/0004-6361/201731620 · Cited by 200 · see citing works
ABIOTIC OZONE AND OXYGEN IN ATMOSPHERES SIMILAR TO PREBIOTIC EARTH
Domagal-Goldman, S. D., Segura, A., Claire, M. W., Robinson, T. D., & Meadows, V. S. (2014) · The Astrophysical Journal · doi:10.1088/0004-637x/792/2/90 · Cited by 198 · see citing works
ABIOTIC O2LEVELS ON PLANETS AROUND F, G, K, AND M STARS: POSSIBLE FALSE POSITIVES FOR LIFE?
Harman, C. E., Schwieterman, E. W., Schottelkotte, J. C., & Kasting, J. F. (2015) · The Astrophysical Journal · doi:10.1088/0004-637x/812/2/137 · Cited by 195 · see citing works
High stellar FUV/NUV ratio and oxygen contents in the atmospheres of potentially habitable planets
Tian, F., France, K., Linsky, J. L., Mauas, P. J. D., & Vieytes, M. C. (2014) · Earth and Planetary Science Letters · doi:10.1016/j.epsl.2013.10.024 · Cited by 183 · see citing works
Habitable worlds with JWST: transit spectroscopy of the TRAPPIST-1 system?
Barstow, J. K., & Irwin, P. G. J. (2016) · Monthly Notices of the Royal Astronomical Society Letters · doi:10.1093/mnrasl/slw109 · Cited by 183 · see citing works
Self-citationEFFECT OF UV RADIATION ON THE SPECTRAL FINGERPRINTS OF EARTH-LIKE PLANETS ORBITING M STARS
Rugheimer, S., Kaltenegger, L., Segura, A., Linsky, J. L., & Mohanty, S. (2015) · The Astrophysical Journal · doi:10.1088/0004-637x/809/1/57 · Cited by 181 · see citing works
Benneke, B., & Seager, S. (2011) · DSpace@MIT (Massachusetts Institute of Technology) · Cited by 181 · see citing works
Disequilibrium biosignatures over Earth history and implications for detecting exoplanet life
Krissansen-Totton, J., Olson, S., & Catling, D. C. (2018) · Science Advances · doi:10.1126/sciadv.aao5747 · Cited by 177 · see citing works
Self-citationReflections on O <sub>2</sub> as a Biosignature in Exoplanetary Atmospheres
Meadows, V. S. (2017) · Astrobiology · doi:10.1089/ast.2016.1578 · Cited by 173 · see citing works
Arney, G., Meadows, V. S., Domagal-Goldman, S. D., Deming, D., Robinson, T. D., Mendoza, G. T., Wolf, E. T., & Schwieterman, E. W. (2017) · The Astrophysical Journal · doi:10.3847/1538-4357/836/1/49 · Cited by 165 · see citing works
Horizontal gene transfer constrains the timing of methanogen evolution
Wolfe, J. M., & Fournier, G. P. (2018) · Nature Ecology & Evolution · doi:10.1038/s41559-018-0513-7 · Cited by 160 · see citing works
Methane absorption coefficients for the jovian planets from laboratory, Huygens, and HST data
Karkoschka, E., & Tomasko, M. G. (2009) · Icarus · doi:10.1016/j.icarus.2009.07.044 · Cited by 152 · see citing works
The Habitability of Proxima Centauri b: Environmental States and Observational Discriminants
Meadows, V. S., Arney, G., Schwieterman, E. W., Lustig‐Yaeger, J., Lincowski, A., Robinson, T., Domagal-Goldman, S. D., Deitrick, R., Barnes, R. K., Fleming, D. P., et al. (2018) · Astrobiology · doi:10.1089/ast.2016.1589 · Cited by 150 · see citing works
Feng, Y. K., Robinson, T. D., Fortney, J. J., Lupu, R. E., Marley, M. S., Lewis, N. K., Macintosh, B., & Line, M. R. (2018) · The Astronomical Journal · doi:10.3847/1538-3881/aab95c · Cited by 138 · see citing works
On Detecting Biospheres from Chemical Thermodynamic Disequilibrium in Planetary Atmospheres
Krissansen-Totton, J., Bergsman, D. S., & Catling, D. C. (2016) · Astrobiology · doi:10.1089/ast.2015.1327 · Cited by 132 · see citing works
Self-citationTransit spectroscopy with James Webb Space Telescope: systematics, starspots and stitching
Barstow, J. K., Aigrain, S., Irwin, P. G. J., Kendrew, S., & Fletcher, L. N. (2015) · Monthly Notices of the Royal Astronomical Society · doi:10.1093/mnras/stv186 · Cited by 128 · see citing works
Self-citationOwen, T. (1980) · Astrophysics and space science library · doi:10.1007/978-94-009-9115-6_17 · Cited by 112 · see citing works
Schwieterman, E. W., Meadows, V. S., Domagal-Goldman, S. D., Deming, D., Arney, G. N., Luger, R., Harman, C. E., Misra, A., & Barnes, R. (2016) · The Astrophysical Journal Letters · doi:10.3847/2041-8205/819/1/l13 · Cited by 111 · see citing works
Hydrogen Consumption by Methanogens on the Early Earth
Kral, T. A., Brink, K. M., Miller, S. L., & McKay, C. P. (1998) · Origins of life and evolution of the biosphere · doi:10.1023/a:1006552412928 · Cited by 107 · see citing works
Strategies for Constraining the Atmospheres of Temperate Terrestrial Planets with JWST
Batalha, N. E., Lewis, N. K., Line, M. R., Valenti, J. A., & Stevenson, K. B. (2018) · The Astrophysical Journal Letters · doi:10.3847/2041-8213/aab896 · Cited by 105 · see citing works
A Coupled Ecosystem-Climate Model for Predicting the Methane Concentration in the Archean Atmosphere
Kasting, J. F., Pavlov, A. A., & Siefert, J. L. (2001) · Origins of Life and Evolution of Biospheres · doi:10.1023/a:1010600401718 · Cited by 100 · see citing works
Strategies for the Search for Life in the Universe
Papagiannis, M. D. (1980) · Astrophysics and space science library · doi:10.1007/978-94-009-9115-6 · Cited by 100 · see citing works
Abiotic Production of Methane in Terrestrial Planets
Guzmán-Marmolejo, A., Segura, A., & Escobar-Briones, E. (2013) · Astrobiology · doi:10.1089/ast.2012.0817 · Cited by 96 · see citing works
False Negatives for Remote Life Detection on Ocean-Bearing Planets: Lessons from the Early Earth
Reinhard, C. T., Olson, S. L., Schwieterman, E. W., & Lyons, T. W. (2017) · Astrobiology · doi:10.1089/ast.2016.1598 · Cited by 93 · see citing works
Common 0.1 bar tropopause in thick atmospheres set by pressure-dependent infrared transparency
Robinson, T. D., & Catling, D. C. (2013) · Nature Geoscience · doi:10.1038/ngeo2020 · Cited by 85 · see citing works
Self-citationCabrol, N. A. (2017) · Astrobiology · doi:10.1089/ast.2017.1756 · Cited by 85 · see citing works
Early 2017 observations of TRAPPIST-1 with Spitzer
Delrez, L., Gillon, M., Triaud, A., Demory, B., DeWit, J., Ingalls, J., Agol, E., Bolmont, É., Burdanov, A., Burgasser, A., et al. (2018) · Monthly Notices of the Royal Astronomical Society · doi:10.1093/mnras/sty051 · Cited by 83 · see citing works
Prospects for detecting oxygen, water, and chlorophyll on an exo-Earth
Brandt, T. D., & Spiegel, D. S. (2014) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.1407296111 · Cited by 66 · see citing works
Possible Bright Starspots on TRAPPIST-1
Morris, B. M., Agol, E., Davenport, J. R. A., & Hawley, S. L. (2018) · The Astrophysical Journal · doi:10.3847/1538-4357/aab6a5 · Cited by 64 · see citing works
Transient Sulfate Aerosols as a Signature of Exoplanet Volcanism
Misra, A., Krissansen‐Totton, J., Koehler, M. C., & Sholes, S. (2015) · Astrobiology · doi:10.1089/ast.2014.1204 · Cited by 62 · see citing works
Self-citationOman, L. D., Waugh, D. W., Pawson, S., et al. (2008) · Journal of the Atmospheric Sciences · doi:10.1175/2008jas2696.1 · Cited by 62 · see citing works
False Negatives for Remote Life Detection on Ocean-Bearing Planets: Lessons from the Early Earth.
Reinhard, C. T., Olson, S. L., Schwieterman, E. W., & Lyons, T. W. (2017) · eScholarship (California Digital Library) · Cited by 48 · see citing works
Bolcar, M. R., Feinberg, L. D., France, K. C., et al. (2016) · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · doi:10.1117/12.2230769 · Cited by 40 · see citing works
The Productivity of Oxygenic Photosynthesis around Cool, M Dwarf Stars
Lehmer, O., Catling, D. C., Parenteau, M. N., & Hoehler, T. M. (2018) · The Astrophysical Journal · doi:10.3847/1538-4357/aac104 · Cited by 39 · see citing works
Self-citationThe transit spectra of Earth and Jupiter
Irwin, P. G. J., Barstow, J. K., Bowles, N. E., Fletcher, L. N., Aigrain, S., & Lee, J.-M. (2014) · Icarus · doi:10.1016/j.icarus.2014.08.005 · Cited by 23 · see citing works
Self-citationNava-Sedeño, J. M., Ortiz-Cervantes, A., Segura, A., & Domagal-Goldman, S. D. (2016) · Astrobiology · doi:10.1089/ast.2015.1435 · Cited by 11 · see citing works
TRAPPIST-1e Has a Large Iron Core
Suissa, G., & Kipping, D. (2018) · Research Notes of the AAS · doi:10.3847/2515-5172/aac32f · Cited by 6 · see citing works
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- Authors
- Krissansen-Totton, J., Garland, R., Irwin, P., & Catling, D. C.
- Affiliations
- University of Oxford (GB)
- University of Washington (US)
- Venue
- The Astronomical Journal
- Publisher
- American Astronomical Society
- Published
- 2018-08-23
- Volume
- 156
- Issue
- 3
- Pages
- 114
- ISSN
- 0004-6256 (ISSN-L)
- 1538-3881
- OpenAlex
- W2888433204
- Cited by
- 145
- References
- 74
- Citations by year
- 2026: 4 · 2025: 14 · 2024: 19 · 2023: 23 · 2022: 21 · 2021: 18 · 2020: 34 · 2019: 12
- FWCI
- 8.59
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Licence
- Locations
- The Astronomical Journal (publishedVersion)
- arXiv (Cornell University) (submittedVersion)
- arXiv (Cornell University)
- Funders
- National Aeronautics and Space Administration (NNX15AR63H, NNA13AA93A)
- NASA Astrobiology Institute (NNA13AA93A)
- NASA Headquarters
- Science and Technology Facilities Council (ST/N00082X/1, ST/N000919/1, ST/K00106X/1)
- Topics
- Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Stellar, planetary, and galactic studies
- Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Space Science and Extraterrestrial Life
- Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Planetary Science and Exploration
- Keywords
- biosignatures, anoxic atmosphere, methane, carbon dioxide, carbon monoxide, TRAPPIST-1e, James Webb Space Telescope, exoplanet atmospheres, biogenic methane, habitable exoplanets, low-mass stars
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