Habitability from Tidally-Induced Tectonics

Abstract

The stability of Earth's climate on geological timescales is enabled by the carbon-silicate cycle that acts as a negative feedback mechanism stabilizing surface temperatures via the intake and outgas of atmospheric carbon. On Earth, this thermostat is enabled by plate tectonics that sequesters outgassed CO2 back into the mantle via weathering and subduction at convergent margins. Here we propose a separate tectonic mechanism -- vertical recycling -- that can serve as the vehicle for CO2 outgassing and sequestration over long timescales. The mechanism requires continuous tidal heating, which makes it particularly relevant to planets in the habitable zone of M stars. Dynamical models of this vertical recycling scenario and stability analysis show that temperate climates stable over Gy timescales are realized for a variety of initial conditions, even as the M star dims over time. The magnitude of equilibrium surface temperatures depends on the interplay of sea weathering and outgassing, which in turn depends on planetary carbon content, so that planets with lower carbon budgets are favoured for temperate conditions. Habitability of planets such as found in the Trappist-1 may be rooted in tidally-driven tectonics.

14 pages, 10 figures, Accepted in Astrophysical Journal

References in corpus (7)

• 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
• The Occurrence and Mass Distribution of Close-in Super-Earths, Neptunes, and Jupiters
• Inevitability of Plate Tectonics on Super-Earths
• Predictions of the atmospheric composition of GJ 1132b
• Tidal Limits to Planetary Habitability
• Secular Effects of Tidal Damping in Compact Planetary Systems

Cited by in corpus (12)

• Water vapour in the atmosphere of the habitable-zone eight Earth-mass planet K2-18 b
• Habitability of Exoplanet Waterworlds
• Habitability of Earth-like stagnant lid planets: Climate evolution and recovery from snowball states
• Carbon cycling and interior evolution of water-covered plate tectonics and stagnant lid planets
• The habitability of stagnant-lid Earths around dwarf stars
• Runaway climate cooling of ocean planets in the habitable zone: a consequence of seafloor weathering enhanced by melting of high-pressure ice
• Climate Diversity in the Solar-Like Habitable Zone due to Varying Background Gas Pressure
• Eta-Earth Revisited II: Deriving a Maximum Number of Earth-like Habitats in the Galactic Disk
• Thermal and orbital evolution of low-mass exoplanets
• Planet-Planet Tides in the TRAPPIST-1 System
• Tidally driven tectonic activity as a parameter in exoplanet habitability
• Diversity of Exoplanets