Fig. 2: Time-evolution of TRAPPIST-1e, with Earth-like initial volatile inventories (no substantial primary atmosphere) from post-accretion magma ocean to present (8 Gyr).
Subplot (a) denotes the time-evolution of surface (orange) and mantle potential temperature (blue), (b) denotes the evolution of outgoing longwave radiation (OLR, blue), absorbed shortwave radiation (ASR, orange), and interior heatflow (green), and subplot (c) shows the evolution of the magma ocean solidification front from the core-mantle boundary to the surface. Subplot (d) shows solid mantle (orange) and magma ocean redox (blue) relative to the Fayalite-Quartz-Magnetite (FMQ) buffer, (e) shows the evolution of atmospheric composition including H2O, H2, CO2, CO, CH4, and O2. Subplot (f) denotes iron speciation in both the magma ocean and the solid silicate mantle—in this oxidizing Earth-analog case no metallic iron is produced. Subplot (g) shows both solid and fluid reservoirs of H; total dissolved hydrogen (purple) and hydrogen dissolved as H2O (blue-dotted) are essentially identical in this oxidized scenario where dissolved H2 is minimal. Subplot (h) denotes solid and fluid reservoirs of C and subplot (i) denotes solid and fluid reservoirs of free oxygen, including oxygen bound to ferric iron, atmospheric species, and O in volatiles dissolved in the melt (H2O, CO2) reservoirs, respectively. Vertical dashed black lines show the termination of the magma ocean, which takes ~4 × 107 years in this case. The short duration of the magma ocean is attributable to the small H inventory, which in turn means limited time for the hydrodynamic drag of C and O; substantial C and O inventories are retained post-magma ocean solidification, and subsequent habitability is not precluded. Note that we do not explicitly model mantle-atmosphere exchange after magma ocean solidification, only escape and stellar evolution.
