Physical constraints on the likelihood of life on exoplanets

Abstract

One of the most fundamental questions in exoplanetology is to determine whether a given planet is habitable. We estimate the relative likelihood of a planet's propensity towards habitability by considering key physical characteristics such as the role of temperature on ecological and evolutionary processes, and atmospheric losses via hydrodynamic escape and stellar wind erosion. From our analysis, we demonstrate that Earth-sized exoplanets in the habitable zone around M-dwarfs seemingly display much lower prospects of being habitable relative to Earth, owing to the higher incident ultraviolet fluxes and closer distances to the host star. We illustrate our results by specifically computing the likelihood (of supporting life) for the recently discovered exoplanets, Proxima b and TRAPPIST-1e, which we find to be several orders of magnitude smaller than that of Earth.

published in International Journal of Astrobiology; 31 pages; 3 figures

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Cited by in corpus (33)

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• Modeling Martian Atmospheric Losses over Time: Implications for Exoplanetary Climate Evolution and Habitability
• Interior Structures and Tidal Heating in the TRAPPIST-1 Planets
• Physical constraints for the evolution of life on exoplanets
• Effects of the stellar wind on the Ly-alpha transit of close-in planets
• The dehydration of water worlds via atmospheric losses
• The Effects of Magnetic Fields on Observational Signatures of Atmospheric Escape in Exoplanets: Double Tail Structures
• Subsurface Exolife
• Dependence of Biological Activity on the Surface Water Fraction of Planets
• Role of planetary obliquity in regulating atmospheric escape: G-dwarf vs. M-dwarf Earth-like exoplanets
• The Propitious Role of Solar Energetic Particles in the Origin of Life
• Predicting the Yield of Potential Venus Analogs from TESS and their Potential for Atmospheric Characterization
• Is Life Most Likely Around Sun-like Stars?
• Implications of tides for life on exoplanets
• Reduced Diversity of Life Around Proxima Centauri and TRAPPIST-1
• Role of stellar physics in regulating the critical steps for life
• Brown Dwarf Atmospheres as the Potentially Most Detectable and Abundant Sites for Life
• Land Fraction Diversity on Earth-like Planets and Implications for their Habitability
• Photosynthesis on Exoplanets and Exomoons from Reflected Light
• Electric sails are potentially more effective than light sails near most stars
• Does the evolution of complex life depend on the stellar spectral energy distribution?
• Multiverse Predictions for Habitability: The Number of Stars and their Properties
• Optimal Target Stars in the Search for Life
• Atmospheric escape in hot Jupiters under sub-Alfvénic interactions
• Prospects for Life on Temperate Planets Around Brown Dwarfs
• Multiverse Predictions for Habitability: Fraction of Planets that Develop Life
• A class of three-dimensional gyroviscous magnetohydrodynamic models
• Dead Zones of Classical Habitability in Stellar Binary Systems
• Theoretical Studies of Comets in the 55 Cancri System
• Chromospheric Activity in 55 Cancri: II. Theoretical Wave Studies versus Observations
• Habitability on local, Galactic and cosmological scales
• Artificial versus Biological Intelligence in the Cosmos: Clues from a Stochastic Analysis of the Drake Equation