Earth-like Exoplanets in Spin–Orbit Resonances: Climate Dynamics, 3D Atmospheric Chemistry, and Observational Signatures
Terrestrial exoplanets around M- and K-type stars are important targets for atmospheric characterization. Such planets are likely tidally locked with the order of spin–orbit resonances (SORs) depending on eccentricity. We explore the impact of SORs on 3D atmospheric dynamics and chemistry, employing...
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IOP Publishing
2025-01-01
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| Series: | The Planetary Science Journal |
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| Online Access: | https://doi.org/10.3847/PSJ/ad9565 |
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| author | Marrick Braam Paul I. Palmer Leen Decin Nathan J. Mayne James Manners Sarah Rugheimer |
| author_facet | Marrick Braam Paul I. Palmer Leen Decin Nathan J. Mayne James Manners Sarah Rugheimer |
| author_sort | Marrick Braam |
| collection | DOAJ |
| description | Terrestrial exoplanets around M- and K-type stars are important targets for atmospheric characterization. Such planets are likely tidally locked with the order of spin–orbit resonances (SORs) depending on eccentricity. We explore the impact of SORs on 3D atmospheric dynamics and chemistry, employing a 3D coupled climate-chemistry model to simulate Proxima Centauri b in 1:1 and 3:2 SORs. For a 1:1 SOR, Proxima Centauri b is in the Rhines rotator circulation regime with dominant zonal gradients (global mean surface temperature 229 K). An eccentric 3:2 SOR warms Proxima Centauri b to 262 K with gradients in the meridional direction. We show how a complex interplay between stellar radiation, orbit, atmospheric circulation, and (photo)chemistry determines the 3D ozone distribution. Spatial variations in ozone column densities align with the temperature distribution and are driven by stratospheric circulation mechanisms. Proxima Centauri b in a 3:2 SOR demonstrates additional atmospheric variability, including daytime–nighttime cycles in water vapor of +55% to −34% and ozone (±5.2%) column densities and periastron–apastron water vapor cycles of +17% to −10%. Synthetic emission spectra for the spectral range of the Large Interferometer For Exoplanets fluctuate by up to 36 ppm with the orbital phase angle for a 1:1 SOR due to 3D spatial and temporal asymmetries. The homogeneous atmosphere for the 3:2 SOR results in relatively constant emission spectra and provides an observational discriminant from the 1:1 SOR. Our work emphasizes the importance of understanding the 3D nature of exoplanet atmospheres and associated spectral variations to determine habitability and interpret atmospheric spectra. |
| format | Article |
| id | doaj-art-aa0ee193c90443b6aaa026f2d384ba3f |
| institution | DOAJ |
| issn | 2632-3338 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Planetary Science Journal |
| spelling | doaj-art-aa0ee193c90443b6aaa026f2d384ba3f2025-08-20T03:05:09ZengIOP PublishingThe Planetary Science Journal2632-33382025-01-0161510.3847/PSJ/ad9565Earth-like Exoplanets in Spin–Orbit Resonances: Climate Dynamics, 3D Atmospheric Chemistry, and Observational SignaturesMarrick Braam0https://orcid.org/0000-0002-9076-2361Paul I. Palmer1https://orcid.org/0000-0002-1487-0969Leen Decin2https://orcid.org/0000-0002-5342-8612Nathan J. Mayne3https://orcid.org/0000-0001-6707-4563James Manners4https://orcid.org/0000-0003-4402-6811Sarah Rugheimer5https://orcid.org/0000-0003-1620-7658School of GeoSciences, University of Edinburgh , Edinburgh, EH9 3FF, UK ; marrick.braam@unibe.ch; Centre for Exoplanet Science, University of Edinburgh , Edinburgh, EH9 3FD, UK; Institute of Astronomy , KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium; Center for Space and Habitability, University of Bern , Gesellschaftsstrasse 6, 3012 Bern, SwitzerlandSchool of GeoSciences, University of Edinburgh , Edinburgh, EH9 3FF, UK ; marrick.braam@unibe.ch; Centre for Exoplanet Science, University of Edinburgh , Edinburgh, EH9 3FD, UKInstitute of Astronomy , KU Leuven, Celestijnenlaan 200D, 3001 Leuven, BelgiumDepartment of Physics and Astronomy, Faculty of Environment Science and Economy, University of Exeter , Exeter EX4 4QL, UKMet Office , Fitzroy Road, Exeter EX1 3PB, UKDepartment of Physics and Astronomy, York University , 4700 Keele Street, Toronto, ON M3J 1P3, CanadaTerrestrial exoplanets around M- and K-type stars are important targets for atmospheric characterization. Such planets are likely tidally locked with the order of spin–orbit resonances (SORs) depending on eccentricity. We explore the impact of SORs on 3D atmospheric dynamics and chemistry, employing a 3D coupled climate-chemistry model to simulate Proxima Centauri b in 1:1 and 3:2 SORs. For a 1:1 SOR, Proxima Centauri b is in the Rhines rotator circulation regime with dominant zonal gradients (global mean surface temperature 229 K). An eccentric 3:2 SOR warms Proxima Centauri b to 262 K with gradients in the meridional direction. We show how a complex interplay between stellar radiation, orbit, atmospheric circulation, and (photo)chemistry determines the 3D ozone distribution. Spatial variations in ozone column densities align with the temperature distribution and are driven by stratospheric circulation mechanisms. Proxima Centauri b in a 3:2 SOR demonstrates additional atmospheric variability, including daytime–nighttime cycles in water vapor of +55% to −34% and ozone (±5.2%) column densities and periastron–apastron water vapor cycles of +17% to −10%. Synthetic emission spectra for the spectral range of the Large Interferometer For Exoplanets fluctuate by up to 36 ppm with the orbital phase angle for a 1:1 SOR due to 3D spatial and temporal asymmetries. The homogeneous atmosphere for the 3:2 SOR results in relatively constant emission spectra and provides an observational discriminant from the 1:1 SOR. Our work emphasizes the importance of understanding the 3D nature of exoplanet atmospheres and associated spectral variations to determine habitability and interpret atmospheric spectra.https://doi.org/10.3847/PSJ/ad9565Exoplanet atmospheresAtmospheric compositionAtmospheric dynamicsChemical kinetics |
| spellingShingle | Marrick Braam Paul I. Palmer Leen Decin Nathan J. Mayne James Manners Sarah Rugheimer Earth-like Exoplanets in Spin–Orbit Resonances: Climate Dynamics, 3D Atmospheric Chemistry, and Observational Signatures The Planetary Science Journal Exoplanet atmospheres Atmospheric composition Atmospheric dynamics Chemical kinetics |
| title | Earth-like Exoplanets in Spin–Orbit Resonances: Climate Dynamics, 3D Atmospheric Chemistry, and Observational Signatures |
| title_full | Earth-like Exoplanets in Spin–Orbit Resonances: Climate Dynamics, 3D Atmospheric Chemistry, and Observational Signatures |
| title_fullStr | Earth-like Exoplanets in Spin–Orbit Resonances: Climate Dynamics, 3D Atmospheric Chemistry, and Observational Signatures |
| title_full_unstemmed | Earth-like Exoplanets in Spin–Orbit Resonances: Climate Dynamics, 3D Atmospheric Chemistry, and Observational Signatures |
| title_short | Earth-like Exoplanets in Spin–Orbit Resonances: Climate Dynamics, 3D Atmospheric Chemistry, and Observational Signatures |
| title_sort | earth like exoplanets in spin orbit resonances climate dynamics 3d atmospheric chemistry and observational signatures |
| topic | Exoplanet atmospheres Atmospheric composition Atmospheric dynamics Chemical kinetics |
| url | https://doi.org/10.3847/PSJ/ad9565 |
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