Statistical Geochemical Constraints on Present-day Water Outgassing as a Source of Secondary Atmospheres on the TRAPPIST-1 Exoplanets
The TRAPPIST-1 planetary system is observationally favorable for studying if planets orbiting M stars can retain atmospheres and host habitable conditions. Recent JWST secondary eclipse observations of TRAPPIST-1 c rule out a thick CO _2 atmosphere but do not rule out atmospheric water vapor or its...
Saved in:
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
|
| Series: | The Planetary Science Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/PSJ/add261 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1850123023895494656 |
|---|---|
| author | Trent B. Thomas Victoria S. Meadows Joshua Krissansen-Totton Megan T. Gialluca Nicholas F. Wogan David C. Catling |
| author_facet | Trent B. Thomas Victoria S. Meadows Joshua Krissansen-Totton Megan T. Gialluca Nicholas F. Wogan David C. Catling |
| author_sort | Trent B. Thomas |
| collection | DOAJ |
| description | The TRAPPIST-1 planetary system is observationally favorable for studying if planets orbiting M stars can retain atmospheres and host habitable conditions. Recent JWST secondary eclipse observations of TRAPPIST-1 c rule out a thick CO _2 atmosphere but do not rule out atmospheric water vapor or its photochemical product, oxygen. Given the high expected escape rate, maintenance of atmospheric water vapor would require a present-day water source, such as volcanic outgassing. Here, we simulate water outgassing on the TRAPPIST-1 planets over a broad phase space that is based on solar system terrestrial bodies. We then apply two filters based on observation and geochemistry that narrow this phase space and constrain the plausible outgassing scenarios. For all seven TRAPPIST-1 planets, we find that the water outgassing rate is most likely ∼0.03x Earth’s but has upper limits of ∼8x Earth’s. The allowed range also implies low, Mars-like magma emplacement rates and relatively dry, Earth-like mantles, although mantle water mass fractions up to 1 wt% are possible. We also present scenarios with magma emplacement rates similar to Mars, Earth, and Io, resulting in different preferred mantle water content and outgassing rates. We find that water outgassing rates are potentially high enough to balance water escape rates, providing a theoretical pathway for the TRAPPIST-1 planets to maintain surface water or water-vapor-containing atmospheres over long timescales. The bounds on outgassing rates and interior properties can be used in atmospheric chemistry and escape models to contextualize future observations of the TRAPPIST-1 planets, and may be applicable to other terrestrial exoplanets. |
| format | Article |
| id | doaj-art-4b9bfe01b9314878a2e91c750dea165c |
| institution | OA Journals |
| issn | 2632-3338 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Planetary Science Journal |
| spelling | doaj-art-4b9bfe01b9314878a2e91c750dea165c2025-08-20T02:34:42ZengIOP PublishingThe Planetary Science Journal2632-33382025-01-016512610.3847/PSJ/add261Statistical Geochemical Constraints on Present-day Water Outgassing as a Source of Secondary Atmospheres on the TRAPPIST-1 ExoplanetsTrent B. Thomas0https://orcid.org/0000-0003-2457-2890Victoria S. Meadows1https://orcid.org/0000-0002-1386-1710Joshua Krissansen-Totton2Megan T. Gialluca3https://orcid.org/0000-0002-2587-0841Nicholas F. Wogan4https://orcid.org/0000-0002-0413-3308David C. Catling5https://orcid.org/0000-0001-5646-120XDepartment of Earth and Space Sciences, University of Washington , Seattle, WA, USA; Astrobiology Program, University of Washington , Seattle, WA, USA; NASA Nexus for Exoplanet System Science, Virtual Planetary Laboratory, University of Washington , Seattle, WA, USAAstrobiology Program, University of Washington , Seattle, WA, USA; NASA Nexus for Exoplanet System Science, Virtual Planetary Laboratory, University of Washington , Seattle, WA, USA; Department of Astronomy, University of Washington , Seattle, WA, USADepartment of Earth and Space Sciences, University of Washington , Seattle, WA, USA; Astrobiology Program, University of Washington , Seattle, WA, USA; NASA Nexus for Exoplanet System Science, Virtual Planetary Laboratory, University of Washington , Seattle, WA, USAAstrobiology Program, University of Washington , Seattle, WA, USA; NASA Nexus for Exoplanet System Science, Virtual Planetary Laboratory, University of Washington , Seattle, WA, USA; Department of Astronomy, University of Washington , Seattle, WA, USANASA Nexus for Exoplanet System Science, Virtual Planetary Laboratory, University of Washington , Seattle, WA, USA; NASA Ames Research Center , Moffett Field, CA 94035, USADepartment of Earth and Space Sciences, University of Washington , Seattle, WA, USA; Astrobiology Program, University of Washington , Seattle, WA, USA; NASA Nexus for Exoplanet System Science, Virtual Planetary Laboratory, University of Washington , Seattle, WA, USAThe TRAPPIST-1 planetary system is observationally favorable for studying if planets orbiting M stars can retain atmospheres and host habitable conditions. Recent JWST secondary eclipse observations of TRAPPIST-1 c rule out a thick CO _2 atmosphere but do not rule out atmospheric water vapor or its photochemical product, oxygen. Given the high expected escape rate, maintenance of atmospheric water vapor would require a present-day water source, such as volcanic outgassing. Here, we simulate water outgassing on the TRAPPIST-1 planets over a broad phase space that is based on solar system terrestrial bodies. We then apply two filters based on observation and geochemistry that narrow this phase space and constrain the plausible outgassing scenarios. For all seven TRAPPIST-1 planets, we find that the water outgassing rate is most likely ∼0.03x Earth’s but has upper limits of ∼8x Earth’s. The allowed range also implies low, Mars-like magma emplacement rates and relatively dry, Earth-like mantles, although mantle water mass fractions up to 1 wt% are possible. We also present scenarios with magma emplacement rates similar to Mars, Earth, and Io, resulting in different preferred mantle water content and outgassing rates. We find that water outgassing rates are potentially high enough to balance water escape rates, providing a theoretical pathway for the TRAPPIST-1 planets to maintain surface water or water-vapor-containing atmospheres over long timescales. The bounds on outgassing rates and interior properties can be used in atmospheric chemistry and escape models to contextualize future observations of the TRAPPIST-1 planets, and may be applicable to other terrestrial exoplanets.https://doi.org/10.3847/PSJ/add261ExoplanetsExoplanet atmospheresPlanetary atmospheresPlanetary geologyPlanetary interiorPlanetary system evolution |
| spellingShingle | Trent B. Thomas Victoria S. Meadows Joshua Krissansen-Totton Megan T. Gialluca Nicholas F. Wogan David C. Catling Statistical Geochemical Constraints on Present-day Water Outgassing as a Source of Secondary Atmospheres on the TRAPPIST-1 Exoplanets The Planetary Science Journal Exoplanets Exoplanet atmospheres Planetary atmospheres Planetary geology Planetary interior Planetary system evolution |
| title | Statistical Geochemical Constraints on Present-day Water Outgassing as a Source of Secondary Atmospheres on the TRAPPIST-1 Exoplanets |
| title_full | Statistical Geochemical Constraints on Present-day Water Outgassing as a Source of Secondary Atmospheres on the TRAPPIST-1 Exoplanets |
| title_fullStr | Statistical Geochemical Constraints on Present-day Water Outgassing as a Source of Secondary Atmospheres on the TRAPPIST-1 Exoplanets |
| title_full_unstemmed | Statistical Geochemical Constraints on Present-day Water Outgassing as a Source of Secondary Atmospheres on the TRAPPIST-1 Exoplanets |
| title_short | Statistical Geochemical Constraints on Present-day Water Outgassing as a Source of Secondary Atmospheres on the TRAPPIST-1 Exoplanets |
| title_sort | statistical geochemical constraints on present day water outgassing as a source of secondary atmospheres on the trappist 1 exoplanets |
| topic | Exoplanets Exoplanet atmospheres Planetary atmospheres Planetary geology Planetary interior Planetary system evolution |
| url | https://doi.org/10.3847/PSJ/add261 |
| work_keys_str_mv | AT trentbthomas statisticalgeochemicalconstraintsonpresentdaywateroutgassingasasourceofsecondaryatmospheresonthetrappist1exoplanets AT victoriasmeadows statisticalgeochemicalconstraintsonpresentdaywateroutgassingasasourceofsecondaryatmospheresonthetrappist1exoplanets AT joshuakrissansentotton statisticalgeochemicalconstraintsonpresentdaywateroutgassingasasourceofsecondaryatmospheresonthetrappist1exoplanets AT megantgialluca statisticalgeochemicalconstraintsonpresentdaywateroutgassingasasourceofsecondaryatmospheresonthetrappist1exoplanets AT nicholasfwogan statisticalgeochemicalconstraintsonpresentdaywateroutgassingasasourceofsecondaryatmospheresonthetrappist1exoplanets AT davidccatling statisticalgeochemicalconstraintsonpresentdaywateroutgassingasasourceofsecondaryatmospheresonthetrappist1exoplanets |