Magma ocean evolution of the TRAPPIST-1 planets

Abstract

Recent observations of the potentially habitable planets TRAPPIST-1 e, f, and g suggest that they possess large water mass fractions of possibly several tens of wt% of water, even though the host star's activity should drive rapid atmospheric escape. These processes can photolyze water, generating free oxygen and possibly desiccating the planet. After the planets formed, their mantles were likely completely molten with volatiles dissolving and exsolving from the melt. In order to understand these planets and prepare for future observations, the magma ocean phase of these worlds must be understood. To simulate these planets, we have combined existing models of stellar evolution, atmospheric escape, tidal heating, radiogenic heating, magma ocean cooling, planetary radiation, and water-oxygen-iron geochemistry. We present MagmOc, a versatile magma ocean evolution model, validated against the rocky Super-Earth GJ 1132b and early Earth. We simulate the coupled magma ocean-atmospheric evolution of TRAPPIST-1 e, f, and g for a range of tidal and radiogenic heating rates, as well as initial water contents between 1 and 100 Earth oceans. We also reanalyze the structures of these planets and find they have water mass fractions of 0-0.23, 0.01-0.21, and 0.11-0.24 for planets e, f, and g, respectively. Our model does not make a strong prediction about the water and oxygen content of the atmosphere of TRAPPIST-1 e at the time of mantle solidification. In contrast, the model predicts that TRAPPIST-1 f and g would have a thick steam atmosphere with a small amount of oxygen at that stage. For all planets that we investigated, we find that only 3-5% of the initial water will be locked in the mantle after the magma ocean solidified.

Accepted for publication in Astrobiology, 24 pages, 9 figures, 7 tables

References in corpus (27)

• Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
• New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
• A terrestrial planet candidate in a temperate orbit around Proxima Centauri
• Habitable Zones Around Main-Sequence Stars: Dependence on Planetary Mass
• Extreme Water Loss and Abiotic O${}_2$ Buildup On Planets Throughout the Habitable Zones of M Dwarfs
• Tidal friction in close-in satellites and exoplanets. The Darwin theory re-visited
• Combining high-dispersion spectroscopy (HDS) with high contrast imaging (HCI): Probing rocky planets around our nearest neighbors
• Highly Siderophile Elements in the Earth's Mantle as a Clock for the Moon-forming Impact
• Revisited Mass-Radius relations for exoplanets below 120 Earth masses
• Observing transiting planets with JWST -- Prime targets and their synthetic spectral observations
• Predictions of the atmospheric composition of GJ 1132b
• Habitable Evaporated Cores: Transforming Mini-Neptunes into Super-Earths in the Habitable Zones of M Dwarfs
• A water budget dichotomy of rocky protoplanets from ${}^{26}$Al-heating
• Detectability of atmospheric features of Earth-like planets in the habitable zone around M dwarfs
• Obliquity-Driven Sculpting of Exoplanetary Systems
• Early 2017 observations of TRAPPIST-1 with $\text{Spitzer}$
• Linking the Climate and Thermal Phase Curve of 55 Cancri e
• Magma oceans and enhanced volcanism on TRAPPIST-1 planets due to induction heating
• What factors affect the duration and outgassing of the terrestrial magma ocean?
• Connecting the dots: A versatile model for the atmospheres of tidally locked Super-Earths
• The persistence of oceans on Earth-like planets: insights from the deep-water cycle
• Hydrogen isotopic evidence for early oxidation of silicate Earth
• The habitability of stagnant-lid Earths around dwarf stars
• Effect of mantle oxidation state and escape upon the evolution of Earth's magma ocean atmosphere
• Detectability of Life Using Oxygen on Pelagic Planets and Water Worlds
• Detecting Proxima b's atmosphere with JWST targeting CO2 at 15 micron using a high-pass spectral filtering technique
• Tides between the TRAPPIST-1 planets

Cited by in corpus (25)

• Retention of water in terrestrial magma oceans and carbon-rich early atmospheres
• Vertically resolved magma ocean-protoatmosphere evolution: H${}_2$, H${}_2$O, CO${}_2$, CH${}_4$, CO, O${}_2$, and N${}_2$ as primary absorbers
• Two temperate super-Earths transiting a nearby late-type M dwarf
• Convective outgassing efficiency in planetary magma oceans: insights from computational fluid dynamics
• Predictions for Observable Atmospheres of Trappist-1 Planets from a Fully Coupled Atmosphere-Interior Evolution Model
• The erosion of large primary atmospheres typically leaves behind substantial secondary atmospheres on temperate rocky planets
• An upper limit on late accretion and water delivery in the Trappist-1 exoplanet system
• Super-Earths and Earth-like Exoplanets
• Understanding planetary context to enable life detection on exoplanets and test the Copernican principle
• Implications of atmospheric nondetections for Trappist-1 inner planets on atmospheric retention prospects for outer planets
• Synergies between Venus & Exoplanetary Observations
• Low volcanic outgassing rates for a stagnant lid Archean Earth with graphite-saturated magmas
• Magma ocean evolution at arbitrary redox state
• Reduced late bombardment on rocky exoplanets around M-dwarfs
• Bioverse: The Habitable Zone Inner Edge Discontinuity as an Imprint of Runaway Greenhouse Climates on Exoplanet Demographics
• The sulphur species in hot rocky exoplanet atmospheres
• Blue marble, stagnant lid: Could dynamic topography avert a waterworld?
• The Abundance of Belatedly Habitable Planets and Ambiguities in Definitions of the Continuously Habitable Zone
• From CO${}_2$- to H${}_2$O-dominated atmospheres and back -- How mixed outgassing changes the volatile distribution in magma oceans around M dwarf stars
• Carbon Cycle Imbalances on Arid Terrestrial Planets with Implications for Venus
• Hidden water in magma ocean exoplanets
• Inversion of Hydrogen-rich Atmosphere and Water Content for GJ 486b
• The effect of a biosphere on the habitable timespan of stagnant-lid planets and implications for the atmospheric spectrum
• An Evolving Cosmic Shoreline and Sandbar Bounding the Rocky Airless Valley
• Simulated Effects of Radioactive Elements on Magnetic Evolution and Atmospheric Mass Loss of Earth-like Planets