Effects of Transient Stellar Emissions on Planetary Climates of Tidally Locked Exo-Earths
Space weather events in exoplanetary environments sourced from transient host star emissions, including stellar flares, coronal mass ejections, and stellar proton events, can substantially influence a planet's habitability and atmospheric evolution history. These time-dependent events may also...
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2025-01-01
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| Series: | The Astronomical Journal |
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| Online Access: | https://doi.org/10.3847/1538-3881/add33e |
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| author | Howard Chen Paolo De Luca Assaf Hochman Thaddeus D. Komacek |
| author_facet | Howard Chen Paolo De Luca Assaf Hochman Thaddeus D. Komacek |
| author_sort | Howard Chen |
| collection | DOAJ |
| description | Space weather events in exoplanetary environments sourced from transient host star emissions, including stellar flares, coronal mass ejections, and stellar proton events, can substantially influence a planet's habitability and atmospheric evolution history. These time-dependent events may also affect our ability to measure and interpret its properties by modulating reservoirs of key chemical compounds and changing the atmosphere’s brightness temperature. The majority of previous work focusing on photochemical effects, ground-level UV dosages, and consequences on observed spectra. Here, using three-dimensional general circulation models with interactive photochemistry, we simulate the climate and chemical impacts of stellar energetic particle events and periodic enhancements of UV photons. We use statistical methods to examine their effects on synchronously rotating TRAPPIST-1e-like planets on a range of spatiotemporal scales. We find that abrupt thermospheric cooling is associated with radiative cooling of NO and CO _2 , and middle-to-lower atmospheric warming is associated with elevated infrared absorbers such as N _2 O and H _2 O. In certain regimes, in particular for climates around moderately active stars, atmospheric temperature changes are strongly affected by O _3 variability. Cumulative effects are largely determined by the flare frequency and the instantaneous effects are dependent on the flare’s spectral shape and energy. In addition to effects on planetary climate and atmospheric chemistry, we find that intense flares can energize the middle atmosphere, causing enhancements in wind velocities up to 40 m s ^−1 in substellar nightsides between 30 and 50 km in altitude. Our results suggest that successive, more energetic eruptive events from younger stars may be a pivotal factor in determining the atmosphere dynamics of their planets. |
| format | Article |
| id | doaj-art-b2635122f79f4f58a3d44761fbc2d707 |
| institution | DOAJ |
| issn | 1538-3881 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astronomical Journal |
| spelling | doaj-art-b2635122f79f4f58a3d44761fbc2d7072025-08-20T03:21:50ZengIOP PublishingThe Astronomical Journal1538-38812025-01-0117014010.3847/1538-3881/add33eEffects of Transient Stellar Emissions on Planetary Climates of Tidally Locked Exo-EarthsHoward Chen0https://orcid.org/0000-0003-1995-1351Paolo De Luca1https://orcid.org/0000-0002-0416-4622Assaf Hochman2https://orcid.org/0000-0002-9881-1893Thaddeus D. Komacek3https://orcid.org/0000-0002-9258-5311Department of Aerospace, Physics, and Space Sciences, Florida Institute of Technology , Melbourne, FL 32901, USA ; hchen@fit.edu; Sellers Exoplanet Environments Collaboration (SEEC) , NASA Goddard Space Flight Center, Greenbelt, MD 20771, USABarcelona Supercomputing Center (BSC) , Barcelona, SpainFredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem , Jerusalem, IsraelDepartment of Physics (Atmospheric, Oceanic and Planetary Physics), University of Oxford , Oxford OX1 3PU, UK; Blue Marble Space Institute of Science , Seattle, WA 98104, USASpace weather events in exoplanetary environments sourced from transient host star emissions, including stellar flares, coronal mass ejections, and stellar proton events, can substantially influence a planet's habitability and atmospheric evolution history. These time-dependent events may also affect our ability to measure and interpret its properties by modulating reservoirs of key chemical compounds and changing the atmosphere’s brightness temperature. The majority of previous work focusing on photochemical effects, ground-level UV dosages, and consequences on observed spectra. Here, using three-dimensional general circulation models with interactive photochemistry, we simulate the climate and chemical impacts of stellar energetic particle events and periodic enhancements of UV photons. We use statistical methods to examine their effects on synchronously rotating TRAPPIST-1e-like planets on a range of spatiotemporal scales. We find that abrupt thermospheric cooling is associated with radiative cooling of NO and CO _2 , and middle-to-lower atmospheric warming is associated with elevated infrared absorbers such as N _2 O and H _2 O. In certain regimes, in particular for climates around moderately active stars, atmospheric temperature changes are strongly affected by O _3 variability. Cumulative effects are largely determined by the flare frequency and the instantaneous effects are dependent on the flare’s spectral shape and energy. In addition to effects on planetary climate and atmospheric chemistry, we find that intense flares can energize the middle atmosphere, causing enhancements in wind velocities up to 40 m s ^−1 in substellar nightsides between 30 and 50 km in altitude. Our results suggest that successive, more energetic eruptive events from younger stars may be a pivotal factor in determining the atmosphere dynamics of their planets.https://doi.org/10.3847/1538-3881/add33eExoplanet atmospheresExoplanet atmospheric variabilityStellar flaresPlanetary climates |
| spellingShingle | Howard Chen Paolo De Luca Assaf Hochman Thaddeus D. Komacek Effects of Transient Stellar Emissions on Planetary Climates of Tidally Locked Exo-Earths The Astronomical Journal Exoplanet atmospheres Exoplanet atmospheric variability Stellar flares Planetary climates |
| title | Effects of Transient Stellar Emissions on Planetary Climates of Tidally Locked Exo-Earths |
| title_full | Effects of Transient Stellar Emissions on Planetary Climates of Tidally Locked Exo-Earths |
| title_fullStr | Effects of Transient Stellar Emissions on Planetary Climates of Tidally Locked Exo-Earths |
| title_full_unstemmed | Effects of Transient Stellar Emissions on Planetary Climates of Tidally Locked Exo-Earths |
| title_short | Effects of Transient Stellar Emissions on Planetary Climates of Tidally Locked Exo-Earths |
| title_sort | effects of transient stellar emissions on planetary climates of tidally locked exo earths |
| topic | Exoplanet atmospheres Exoplanet atmospheric variability Stellar flares Planetary climates |
| url | https://doi.org/10.3847/1538-3881/add33e |
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