Related Experiment Video
Updated: Jul 19, 2025
13:27
Exploring the Effects of Atmospheric Forcings on Evaporation: Experimental Integration of the Atmospheric Boundary Layer and Shallow Subsurface
Published on: June 8, 2015
8.8K
A cool runaway greenhouse without surface magma ocean.
Franck Selsis1, Jérémy Leconte2, Martin Turbet2,3
1Laboratoire d'astrophysique de Bordeaux, University of Bordeaux, CNRS, Pessac, France. franck.selsis@u-bordeaux.fr.
Nature
|August 9, 2023
Summary
Pure steam atmospheres on planets are shaped by radiative layers, not just convection. This means surface magma oceans are less likely than previously thought, impacting exoplanet habitability assessments.
Area of Science:
- Planetary Science
- Climate Modeling
- Astrophysics
Background:
- Previous models assumed fully convective steam atmospheres, predicting surface magma oceans.
- These assumptions were based on Earth-like water content and high insolation or impact scenarios.
Purpose of the Study:
- To investigate the thermal structure of pure steam atmospheres using a consistent climate model.
- To reassess the conditions necessary for surface magma ocean formation and planetary crust solidification.
Main Methods:
- Utilized a consistent climate model to simulate pure steam atmospheres.
- Analyzed the impact of radiative layers, stellar spectrum, and internal heat flow on thermal structure.
- Compared model predictions with previous assumptions of adiabatic structures.
Main Results:
- Steam atmospheres are predominantly shaped by radiative layers, making their thermal structure dependent on stellar spectrum and internal heat.
- Surface temperatures are cooler without imposed adiabatic profiles; significant insolation is needed to melt Earth's crust.
- Surface magma oceans are unlikely around cooler stars, and Venus's surface may solidify before its steam atmosphere escapes.
Conclusions:
- Rethinks the formation of surface magma oceans and the evolution of steam atmospheres on terrestrial planets.
- Highlights the need for improved opacity measurements for accurate modeling of exoplanet atmospheres.
- Impacts understanding of exoplanet mass-radius relationships and habitability, particularly for systems like TRAPPIST-1.
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