Solar XUV and ENA-driven water loss from early Venus' steam atmosphere

Abstract

The influence of the hydrogen hydrodynamic upper atmosphere escape, driven by the solar soft X-ray and extreme ultraviolet radiation (XUV) flux, on an expected magma ocean outgassed steam atmosphere of early Venus is studied. By assuming that the young Sun was either a weak or moderate active young G star, we estimated the water loss from a hydrogen dominated thermosphere due to the absorption of the solar XUV flux and the precipitation of solar wind produced energetic hydrogen atoms (ENAs). The production of ENAs and their interaction with the hydrodynamic extended upper atmosphere, including collision-related feedback processes, have been calculated by means of Monte Carlo models. ENAs that collide in the upper atmosphere deposit their energy and heat the surrounding gas mainly above the main XUV energy deposition layer. It is shown that precipitating ENAs modify the thermal structure of the upper atmosphere, but the enhancement of the thermal escape rates caused by these energetic hydrogen atoms is negligible. Our results also indicate that the majority of oxygen arising from dissociated H${}_2$O molecules is left behind during the first 100 Myr. It is thus suggested that the main part of the remaining oxygen has been absorbed by crustal oxidation.

6 figures and 2 tables

References in corpus (10)

• Atmospheric Escape from Hot Jupiters
• Extreme Water Loss and Abiotic O${}_2$ Buildup On Planets Throughout the Habitable Zones of M Dwarfs
• The Extreme Ultraviolet and X-Ray Sun in Time: High-Energy Evolutionary Tracks of a Solar-Like Star
• Stellar Winds on the Main-Sequence II: the Evolution of Rotation and Winds
• Heating efficiency in hydrogen-dominated upper atmospheres
• Stellar Winds on the Main-Sequence I: Wind Model
• A search for flares and mass ejections on young late-type stars in the open cluster Blanco-1
• Extreme hydrodynamic atmospheric loss near the critical thermal escape regime
• Impact inducted surface heating by planetesimals on early Mars
• Asymmetries in Mars' Exosphere: Implications for X-ray and ENA Imaging

Cited by in corpus (19)

• Venusian Habitable Climate Scenarios: Modeling Venus through time and applications to slowly rotating Venus-Like Exoplanets
• Day-night cloud asymmetry prevents early oceans on Venus but not on Earth
• The High-Energy Radiation Environment Around a 10 Gyr M Dwarf: Habitable at Last?
• 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
• Hydrodynamic escape of water vapor atmospheres near very active stars
• Predictions for Observable Atmospheres of Trappist-1 Planets from a Fully Coupled Atmosphere-Interior Evolution Model
• Dry Late Accretion inferred from Venus' coupled atmosphere and internal evolution
• The erosion of large primary atmospheres typically leaves behind substantial secondary atmospheres on temperate rocky planets
• Observing Isotopologue Bands in Terrestrial Exoplanet Atmospheres with the James Webb Space Telescope---Implications for Identifying Past Atmospheric and Ocean Loss
• The Fundamental Connections Between the Solar System and Exoplanetary Science
• Implications of atmospheric nondetections for Trappist-1 inner planets on atmospheric retention prospects for outer planets
• Transit Ly-$\alpha$ signatures of terrestrial planets in the habitable zones of M dwarfs
• Heating and ionization by non-thermal electrons in the upper atmospheres of water-rich exoplanets
• Evolution of the Earth's Polar Outflow From Mid-Archean to Present
• Modification of the radioactive heat budget of Earth-like exoplanets by the loss of primordial atmospheres
• Detecting Stellar Coronal Mass Ejections via Coronal Dimming in the Extreme Ultraviolet
• Takeout and Delivery: Erasing the Dusty Signature of Late-stage Terrestrial Planet Formation
• Inversion of Hydrogen-rich Atmosphere and Water Content for GJ 486b