Was Venus Ever Habitable? Constraints from a Coupled Interior-Atmosphere-Redox Evolution Model

Abstract

Venus's past climate evolution is uncertain. General circulation model simulations permit a habitable climate as late as ~0.7 Ga, and there is suggestive-albeit inconclusive-evidence for previous liquid water from surface geomorphology and mineralogy. However, it is unclear whether a habitable past can be reconciled with Venus's inferred atmospheric evolution. In particular, the lack of leftover atmospheric oxygen argues against recent water loss. Here, we apply a fully coupled model of Venus's atmospheric-interior-climate evolution from post-accretion magma ocean to present. The model self-consistently tracks C-, H-, and O-bearing volatiles and surface climate through the entirety of Venus's history. Atmospheric escape, mantle convection, melt production, outgassing, deep water cycling, and carbon cycling are explicitly coupled to climate and redox evolution. Plate tectonic and stagnant lid histories are considered. Using this coupled model, we conclude that both a habitable Venusian past and one where Venus never possessed liquid surface water can be reconciled with known constraints. Specifically, either scenario can reproduce bulk atmospheric composition, inferred surface heat flow, and observed ${}^{40}$Ar and ${}^4$He. Moreover, the model suggests that Venus could have been habitable with a ~100 m global ocean as late as 1 Ga, without violating any known constraints. In fact, if diffusion-limited water loss is throttled by a cool, CO${}_2$-dominated upper atmosphere, then a habitable past is tentatively favored by our model. This escape throttling makes it difficult to simultaneously recover negligible water vapor and ~90 bar CO${}_2$ in the modern atmosphere without temporarily sequestering carbon in the interior via silicate weathering to enhance H escape.

Complete text 27 pages (main text 16 pages), including 9 figures and 7 supplementary figures

References in corpus (17)

• Was Venus the First Habitable World of our Solar System?
• The Extreme Ultraviolet and X-Ray Sun in Time: High-Energy Evolutionary Tracks of a Solar-Like Star
• The Detectability and Characterization of the TRAPPIST-1 Exoplanet Atmospheres with JWST
• Abiotic oxygen-dominated atmospheres on terrestrial habitable zone planets
• Geodynamics and Rate of Volcanism on Massive Earth-like Planets
• Predictions of the atmospheric composition of GJ 1132b
• What factors affect the duration and outgassing of the terrestrial magma ocean?
• The Role of N2 as a Geo-Biosignature for the Detection and Characterization of Earth-like Habitats
• Escape and fractionation of volatiles and noble gases from Mars-sized planetary embryos and growing protoplanets
• Re-analysis of the 267-GHz ALMA observations of Venus: No statistically significant detection of phosphine
• Abundant atmospheric methane from volcanism on terrestrial planets is unlikely and strengthens the case for methane as a biosignature
• The persistence of oceans on Earth-like planets: insights from the deep-water cycle
• Oxygen False Positives on Habitable Zone Planets Around Sun-Like Stars
• Complications in the ALMA Detection of Phosphine at Venus
• Observing Isotopologue Bands in Terrestrial Exoplanet Atmospheres with the James Webb Space Telescope---Implications for Identifying Past Atmospheric and Ocean Loss
• Beyond runaway: initiation of the post-runaway greenhouse state on rocky exoplanets
• A mirage of the cosmic shoreline: Venus-like clouds as a statistical false positive for exoplanet atmospheric erosion

Cited by in corpus (13)

• The long-term evolution of the atmosphere of Venus: processes and feedback mechanisms
• 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
• Implications of atmospheric nondetections for Trappist-1 inner planets on atmospheric retention prospects for outer planets
• Synergies between Venus & Exoplanetary Observations
• Bioverse: The Habitable Zone Inner Edge Discontinuity as an Imprint of Runaway Greenhouse Climates on Exoplanet Demographics
• Interior Controls on the Habitability of Rocky Planets
• Atmospheric carbon depletion as a tracer of water oceans and biomass on temperate terrestrial exoplanets
• Blue marble, stagnant lid: Could dynamic topography avert a waterworld?
• The origin of Earth's mantle nitrogen: primordial or early biogeochemical cycling?
• AGNI: A radiative-convective model for lava planet atmospheres
• Carbon Cycle Imbalances on Arid Terrestrial Planets with Implications for Venus
• Evolution and Observable Properties of Rocky Planet Atmospheres