Evolution of Earth-like planetary atmospheres around M-dwarf stars: Assessing the atmospheres and biospheres with a coupled atmosphere biogeochemical model

Abstract

Earth-like planets orbiting M-dwarfs are prominent future targets when searching for life outside the solar system. We apply our newly developed Coupled Atmosphere Biogeochemistry model to investigate the coupling between the biosphere, geosphere and atmosphere to gain deeper insight into the atmospheric evolution of Earth-like planets orbiting M-dwarfs. Our main goal is to understand better atmospheric processes affecting biosignatures and climate on such worlds. Furthermore, this is the first study to our knowledge which applies an automated chemical pathway analysis quantifying the production and destruction pathways of O${}_2$ for an Earth-like planet with an Archean O${}_2$ abundance orbiting in the habitable zone of the M-dwarf AD Leo. Results suggest that the main production arises in the upper atmosphere from CO${}_2$ photolysis followed by catalytic HO${}_x$ reactions. The strongest destruction does not take place in the troposphere, as was the case in Gebauer et al. (2017) for an early-Earth analog planet around the Sun, but instead in the middle atmosphere where H${}_2$O photolysis is the strongest. This result was driven by the strong Lyman-$\alpha$-radiation output of AD Leo, which efficiently photolyzes H${}_2$O. Results further suggest that early Earth-like atmospheres of planets orbiting an M-dwarf like AD Leo are in absolute terms less destructive for atmospheric O${}_2$ than for early-Earth analog planets around the Sun despite higher concentrations of reduced gases such as e.g. H${}_2$, CH${}_4$ and CO. Hence the net primary productivity (NPP) required to produce the same amount of atmospheric O${}_2$ at the surface is reduced. This implies that a possible Great Oxidation event, analogous to that on Earth, would have occurred earlier in time in analog atmospheres around M-dwarfs.

arXiv comment40 pages, 22 figures, 2 tables, peer-review Version, final publication is available from Mary Ann Liebert, Inc., publishers http://doi.org/10.1089/ast.2017.1723

References in corpus (37)

• Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
• A terrestrial planet candidate in a temperate orbit around Proxima Centauri
• The NextGen Model Atmosphere grid for $3000\le \Teff \le 10000\K$
• Temperate Earth-sized planets transiting a nearby ultracool dwarf star
• Extreme Water Loss and Abiotic O${}_2$ Buildup On Planets Throughout the Habitable Zones of M Dwarfs
• Habitable planets around the star Gl 581?
• Biosignatures from Earth-Like Planets Around M Dwarfs
• Stabilizing Cloud Feedback Dramatically Expands the Habitable Zone of Tidally Locked Planets
• A Re-appraisal of the Habitability of Planets Around M Dwarf Stars
• The Habitability of Planets Orbiting M-dwarf Stars
• Photochemistry in Terrestrial Exoplanet Atmospheres I: Photochemistry Model and Benchmark Cases
• Spectral signatures of photosynthesis II: coevolution with other stars and the atmosphere on extrasolar worlds
• Strong Dependence of the Inner Edge of the Habitable Zone on Planetary Rotation Rate
• The MUSCLES Treasury Survey II: Intrinsic Lyman Alpha and Extreme Ultraviolet Spectra of K and M Dwarfs with Exoplanets
• The inner edge of the habitable zone for synchronously rotating planets around low-mass stars using general circulation models
• The MUSCLES Treasury Survey III: X-ray to Infrared Spectra of 11 M and K Stars Hosting Planets
• Assessing the Habitability of the TRAPPIST-1 System Using a 3D Climate Model
• Abiotic Ozone and Oxygen in Atmospheres Similar to Prebiotic Earth
• Habitable Moist Atmospheres On Terrestrial Planets Near the Inner Edge Of the Habitable Zone Around M-dwarfs
• Abiotic O${}_2$ Levels on Planets around F, G, K, and M Stars: Possible False Positives for Life?
• High Stellar FUV/NUV Ratio and Oxygen Contents in the Atmospheres of Potentially Habitable Planets
• N-body simulations of planetary accretion around M dwarf stars
• Effect of UV Radiation on the Spectral Fingerprints of Earth-like Planets Orbiting M dwarfs
• Predictions of the atmospheric composition of GJ 1132b
• UV Surface Environment of Earth-like Planets Orbiting FGKM Stars Through Geological Evolution
• The Surface UV Environment on Planets Orbiting M-Dwarfs: Implications for Prebiotic Chemistry & Need for Experimental Follow-Up
• Exploring the climate of Proxima B with the Met Office Unified Model
• The Response of Atmospheric Chemistry on Earthlike Planets around F, G and K Stars to Small Variations in Orbital Distance
• On the environment surrounding close-in exoplanets
• Time-resolved Ultraviolet Spectroscopy of the M-dwarf GJ 876 Exoplanetary System
• Atmospheric effects of stellar cosmic rays on Earth-like exoplanets orbiting M-dwarfs
• Biomarker Response to Galactic Cosmic Ray-Induced NOx and the Methane Greenhouse Effect in the Atmosphere of an Earthlike Planet Orbiting an M-Dwarf Star
• Sensitivity of Biosignatures on Earth-like Planets orbiting in the Habitable Zone of Cool M-Dwarf Stars to varying Stellar UV Radiation and Surface Biomass Emissions
• The HADES RV Programme with HARPS-N@TNG - GJ 3998: An early M-dwarf hosting a system of Super-Earths
• Potential Biosignatures in Super-Earth Atmospheres II. Photochemical Responses
• Evolution of Earth-like extrasolar planetary atmospheres: Assessing the atmospheres and biospheres of early Earth analog planets with a coupled atmosphere biogeochemical model
• Possible chromospheric activity cycles in AD Leo

Cited by in corpus (10)

• Detectability of atmospheric features of Earth-like planets in the habitable zone around M dwarfs
• Distinguishing between wet and dry atmospheres of TRAPPIST-1 e and f
• Consistently Simulating a Wide Range of Atmospheric Scenarios for K2-18b with a Flexible Radiative Transfer Module
• A New Model Suite to Determine the Influence of Cosmic Rays on (Exo)planetary Atmospheric Biosignatures -- Validation based on Modern Earth
• Possible Atmospheric Diversity of Low Mass Exoplanets, some Central Aspects
• Dynamics of the Great Oxidation Event from a 3D photochemical-climate model
• High-Resolution Spectral Discriminants of Ocean Loss for M Dwarf Terrestrial Exoplanets
• Influence of Biomass Emissions upon Habitability, Biosignatures and Detectability in Earth-like Atmospheres
• The effect of a biosphere on the habitable timespan of stagnant-lid planets and implications for the atmospheric spectrum
• Possible favored Great Oxidation Event scenario on exoplanets around M-Stars with the example of TRAPPIST-1e