Detecting Atmospheric CO2 Trends as Population-level Signatures for Long-term Stable Water Oceans and Biotic Activity on Temperate Terrestrial Exoplanets
Identifying key observables is essential for enhancing our knowledge of exoplanet habitability and biospheres, as well as improving future mission capabilities. While currently challenging, future observatories such as the Large Interferometer for Exoplanets (LIFE) will enable atmospheric observatio...
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2025-01-01
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| Online Access: | https://doi.org/10.3847/1538-4357/addc6e |
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| author | Janina Hansen Daniel Angerhausen Sascha P. Quanz Derek Vance Björn S. Konrad Emily O. Garvin Eleonora Alei Jens Kammerer Felix A. Dannert |
| author_facet | Janina Hansen Daniel Angerhausen Sascha P. Quanz Derek Vance Björn S. Konrad Emily O. Garvin Eleonora Alei Jens Kammerer Felix A. Dannert |
| author_sort | Janina Hansen |
| collection | DOAJ |
| description | Identifying key observables is essential for enhancing our knowledge of exoplanet habitability and biospheres, as well as improving future mission capabilities. While currently challenging, future observatories such as the Large Interferometer for Exoplanets (LIFE) will enable atmospheric observations of a diverse sample of temperate terrestrial worlds. Using thermal emission spectra that represent conventional predictions of atmospheric CO _2 variability across the habitable zone (HZ), we assess the ability of the LIFE mission—as a specific concept for a future space-based interferometer—to detect CO _2 trends indicative of the carbonate–silicate (Cb–Si) weathering feedback, a well-known habitability marker and potential biological tracer. Therefore, we explore the feasibility of differentiating between CO _2 trends in biotic and abiotic planet populations. We create synthetic exoplanet populations based on geochemistry-climate predictions and perform retrievals on simulated thermal emission observations. The results demonstrate the robust detection of population-level CO _2 trends in both biotic and abiotic scenarios for population sizes as small as 30 exo-Earth candidates (EECs) and the lowest assessed spectrum quality in terms of signal-to-noise ratio, S/N = 10, and spectral resolution, R = 50. However, biased CO _2 partial pressure constraints hinder accurate differentiation between biotic and abiotic trends. If these biases were corrected, accurate differentiation could be achieved for populations with ≥100 EECs. We conclude that LIFE can effectively enable population-level characterization of temperate terrestrial atmospheres and detect CO _2 trends driven by the Cb–Si cycle as habitability indicators. Nevertheless, the identified biases underscore the importance of testing atmospheric characterization performance against the broad diversity expected for planetary populations. |
| format | Article |
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| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal |
| spelling | doaj-art-ff173438bbfb437eb3e5de0d0c2e6db92025-08-20T03:39:31ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01988111610.3847/1538-4357/addc6eDetecting Atmospheric CO2 Trends as Population-level Signatures for Long-term Stable Water Oceans and Biotic Activity on Temperate Terrestrial ExoplanetsJanina Hansen0https://orcid.org/0009-0003-1247-8378Daniel Angerhausen1https://orcid.org/0000-0001-6138-8633Sascha P. Quanz2https://orcid.org/0000-0003-3829-7412Derek Vance3https://orcid.org/0000-0002-6140-6325Björn S. Konrad4https://orcid.org/0000-0002-9912-8340Emily O. Garvin5https://orcid.org/0000-0003-2530-9330Eleonora Alei6https://orcid.org/0000-0002-0006-1175Jens Kammerer7https://orcid.org/0000-0003-2769-0438Felix A. Dannert8https://orcid.org/0000-0002-5476-2663ETH Zurich , Institute for Particle Physics & Astrophysics, Wolfgang-Pauli-Str. 27, 8093 Zurich, Switzerland ; jahansen@phys.ethz.ch; National Centre of Competence in Research PlanetS , SwitzerlandETH Zurich , Institute for Particle Physics & Astrophysics, Wolfgang-Pauli-Str. 27, 8093 Zurich, Switzerland ; jahansen@phys.ethz.ch; National Centre of Competence in Research PlanetS , Switzerland; Blue Marble Space Institute of Science , Seattle, WA 98104, USA; SETI Institute , 189 N. Bernado Avenue, Mountain View, CA 94043, USAETH Zurich , Institute for Particle Physics & Astrophysics, Wolfgang-Pauli-Str. 27, 8093 Zurich, Switzerland ; jahansen@phys.ethz.ch; National Centre of Competence in Research PlanetS , Switzerland; ETH Zurich , Department of Earth and Planetary Sciences, Sonneggstrasse 5, 8092 Zurich, SwitzerlandETH Zurich , Institute of Geochemistry and Petrology, Department of Earth and Planetary Sciences, Clausiusstrasse 25, 8092 Zurich, SwitzerlandETH Zurich , Institute for Particle Physics & Astrophysics, Wolfgang-Pauli-Str. 27, 8093 Zurich, Switzerland ; jahansen@phys.ethz.ch; National Centre of Competence in Research PlanetS , SwitzerlandETH Zurich , Institute for Particle Physics & Astrophysics, Wolfgang-Pauli-Str. 27, 8093 Zurich, Switzerland ; jahansen@phys.ethz.ch; National Centre of Competence in Research PlanetS , SwitzerlandNASA Goddard Space Flight Center , 8800 Goddard Road, Greenbelt, MD 20771, USAEuropean Southern Observatory , Karl-Schwarzschild-Straße 2, 85748 Garching, GermanyETH Zurich , Institute for Particle Physics & Astrophysics, Wolfgang-Pauli-Str. 27, 8093 Zurich, Switzerland ; jahansen@phys.ethz.ch; National Centre of Competence in Research PlanetS , SwitzerlandIdentifying key observables is essential for enhancing our knowledge of exoplanet habitability and biospheres, as well as improving future mission capabilities. While currently challenging, future observatories such as the Large Interferometer for Exoplanets (LIFE) will enable atmospheric observations of a diverse sample of temperate terrestrial worlds. Using thermal emission spectra that represent conventional predictions of atmospheric CO _2 variability across the habitable zone (HZ), we assess the ability of the LIFE mission—as a specific concept for a future space-based interferometer—to detect CO _2 trends indicative of the carbonate–silicate (Cb–Si) weathering feedback, a well-known habitability marker and potential biological tracer. Therefore, we explore the feasibility of differentiating between CO _2 trends in biotic and abiotic planet populations. We create synthetic exoplanet populations based on geochemistry-climate predictions and perform retrievals on simulated thermal emission observations. The results demonstrate the robust detection of population-level CO _2 trends in both biotic and abiotic scenarios for population sizes as small as 30 exo-Earth candidates (EECs) and the lowest assessed spectrum quality in terms of signal-to-noise ratio, S/N = 10, and spectral resolution, R = 50. However, biased CO _2 partial pressure constraints hinder accurate differentiation between biotic and abiotic trends. If these biases were corrected, accurate differentiation could be achieved for populations with ≥100 EECs. We conclude that LIFE can effectively enable population-level characterization of temperate terrestrial atmospheres and detect CO _2 trends driven by the Cb–Si cycle as habitability indicators. Nevertheless, the identified biases underscore the importance of testing atmospheric characterization performance against the broad diversity expected for planetary populations.https://doi.org/10.3847/1538-4357/addc6eHabitable zoneExoplanet atmospheresBiosignaturesExoplanet atmospheric variabilityInfrared spectroscopySpace telescopes |
| spellingShingle | Janina Hansen Daniel Angerhausen Sascha P. Quanz Derek Vance Björn S. Konrad Emily O. Garvin Eleonora Alei Jens Kammerer Felix A. Dannert Detecting Atmospheric CO2 Trends as Population-level Signatures for Long-term Stable Water Oceans and Biotic Activity on Temperate Terrestrial Exoplanets The Astrophysical Journal Habitable zone Exoplanet atmospheres Biosignatures Exoplanet atmospheric variability Infrared spectroscopy Space telescopes |
| title | Detecting Atmospheric CO2 Trends as Population-level Signatures for Long-term Stable Water Oceans and Biotic Activity on Temperate Terrestrial Exoplanets |
| title_full | Detecting Atmospheric CO2 Trends as Population-level Signatures for Long-term Stable Water Oceans and Biotic Activity on Temperate Terrestrial Exoplanets |
| title_fullStr | Detecting Atmospheric CO2 Trends as Population-level Signatures for Long-term Stable Water Oceans and Biotic Activity on Temperate Terrestrial Exoplanets |
| title_full_unstemmed | Detecting Atmospheric CO2 Trends as Population-level Signatures for Long-term Stable Water Oceans and Biotic Activity on Temperate Terrestrial Exoplanets |
| title_short | Detecting Atmospheric CO2 Trends as Population-level Signatures for Long-term Stable Water Oceans and Biotic Activity on Temperate Terrestrial Exoplanets |
| title_sort | detecting atmospheric co2 trends as population level signatures for long term stable water oceans and biotic activity on temperate terrestrial exoplanets |
| topic | Habitable zone Exoplanet atmospheres Biosignatures Exoplanet atmospheric variability Infrared spectroscopy Space telescopes |
| url | https://doi.org/10.3847/1538-4357/addc6e |
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