Atmospheric evolution through outgassing and escape on young molten rocky exoplanets
- 1Kapteyn Astronomical Institute, University of Groningen
- 2Institute of Astronomy, University of Cambridge
- 3Netherlands eScience Center
Abstract
Context. The earliest rocky planet atmospheres were shaped by the competition between initial volatile inventories and atmospheric escape driven by stellar irradiation. On young magma ocean planets, volatile exchange between the atmosphere and the interior through in- and outgassing competes with atmospheric escape, controlling volatile retention and atmospheric evolution. Aims. We investigate how atmospheric escape and replenishment via outgassing during magma ocean crystallization shape rocky exoplanet atmospheres. Methods. We extended a coupled interior-atmosphere model to simulate rocky planet evolution during the magma ocean era by incorporating an energy-limited atmospheric escape module. Comparing self-consistent radiative-convective and prescribed-convective atmospheres, we quantified how atmospheric energy transport affects escape. We explored a wide range of orbital separations, escape efficiencies, oxidation states, and initial volatile inventories to identify regimes where sustained magma-ocean outgassing or escape dominates. We estimated atmospheric mass loss and compositions for young rocky planets around Sun-like and M dwarf stars over geologic timescales. Results. Atmospheric escape shortens magma ocean lifetimes by weakening greenhouse insulation and accelerating cooling, with radiative-convective atmospheres reducing solidification timescales compared to purely convective cases. Volatile dissolution into the magma ocean interacts with the escape of atmospheric species to chemically fractionate the planetary volatile budget over time by retaining more soluble species. For Earth-mass planets, atmospheres survive if mass-loss rates remain moderate (ṀEL ≈ 1010 g s−1). When atmospheric escape is included, the mantle redox state remains a key control on atmospheric composition: high oxygen fugacity (fO2) yields heavier H2O- and CO2-rich atmospheres, while low fO2 produces light H2- or CO-dominated atmospheres, consistent with previous studies. Orbital separation, initial volatile inventory, and stellar type produce diverse evolutionary pathways, from bare rocky planets to magma oceans with thick atmospheres, spanning compositions from H2- to SO2-dominated atmospheres.
Related
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- Hydrogen and Helium Dissolution, Outgassing, and Loss in Evolving Sub-Neptune Magma Oceans: Examining Demographic Features and Radius Evolution
- Hydrogen and Helium Dissolution, Outgassing, and Loss in Evolving Sub-Neptune Magma Oceans: Examining Demographic Features and Radius Evolution
- Effect of tidal gravity and planetary rotation on the retrieved atmospheric abundances of close-in exoplanets
BibTeX
@article{emma2026atmospheric,
title = {{Atmospheric evolution through outgassing and escape on young molten rocky exoplanets}},
author = {Postolec Emma and Lichtenberg Tim and Nicholls Harrison and Soucasse Laurent and van der Tak Floris},
journal = {Astronomy \& Astrophysics},
year = {2026},
month = oct,
doi = {10.1051/0004-6361/202659336},
url = {https://doi.org/10.1051/0004-6361/202659336},
note = {CC BY},
}
RIS
TY - JOUR
TI - Atmospheric evolution through outgassing and escape on young molten rocky exoplanets
AU - Postolec Emma
AU - Lichtenberg Tim
AU - Nicholls Harrison
AU - Soucasse Laurent
AU - van der Tak Floris
PY - 2026
DA - 2026/10/24
JO - Astronomy & Astrophysics
DO - 10.1051/0004-6361/202659336
UR - https://doi.org/10.1051/0004-6361/202659336
AB - Context. The earliest rocky planet atmospheres were shaped by the competition between initial volatile inventories and atmospheric escape driven by stellar irradiation. On young magma ocean planets, volatile exchange between the atmosphere and the interior through in- and outgassing competes with atmospheric escape, controlling volatile retention and atmospheric evolution. Aims. We investigate how atmospheric escape and replenishment via outgassing during magma ocean crystallization shape rocky exoplanet atmospheres. Methods. We extended a coupled interior-atmosphere model to simulate rocky planet evolution during the magma ocean era by incorporating an energy-limited atmospheric escape module. Comparing self-consistent radiative-convective and prescribed-convective atmospheres, we quantified how atmospheric energy transport affects escape. We explored a wide range of orbital separations, escape efficiencies, oxidation states, and initial volatile inventories to identify regimes where sustained magma-ocean outgassing or escape dominates. We estimated atmospheric mass loss and compositions for young rocky planets around Sun-like and M dwarf stars over geologic timescales. Results. Atmospheric escape shortens magma ocean lifetimes by weakening greenhouse insulation and accelerating cooling, with radiative-convective atmospheres reducing solidification timescales compared to purely convective cases. Volatile dissolution into the magma ocean interacts with the escape of atmospheric species to chemically fractionate the planetary volatile budget over time by retaining more soluble species. For Earth-mass planets, atmospheres survive if mass-loss rates remain moderate (ṀEL ≈ 1010 g s−1). When atmospheric escape is included, the mantle redox state remains a key control on atmospheric composition: high oxygen fugacity (fO2) yields heavier H2O- and CO2-rich atmospheres, while low fO2 produces light H2- or CO-dominated atmospheres, consistent with previous studies. Orbital separation, initial volatile inventory, and stellar type produce diverse evolutionary pathways, from bare rocky planets to magma oceans with thick atmospheres, spanning compositions from H2- to SO2-dominated atmospheres.
SN - 0004-6361
SN - 1432-0746
ER -