Loss and fractionation of noble gas isotopes and moderately volatile elements from planetary embryos and early Venus, Earth and Mars

Abstract

Here we discuss the current state of knowledge on how atmospheric escape processes can fractionate noble gas isotopes and moderately volatile rock-forming elements that populate primordial atmospheres, magma ocean related environments, and catastrophically outgassed steam atmospheres. Variations of isotopes and volatile elements in different planetary reservoirs keep information about atmospheric escape, composition and even the source of accreting material. We summarize our knowledge on atmospheric isotope ratios and discuss the latest evidence that proto-Venus and Earth captured small H${}_2$-dominated primordial atmospheres that were lost by EUV-driven hydrodynamic escape after the disk dispersed. All relevant thermal and non-thermal atmospheric escape processes that can fractionate various isotopes and volatile elements are discussed. Erosion of early atmospheres, crust and mantle by large planetary impactors are also addressed. Further, we discuss how moderately volatile elements such as the radioactive heat producing element ${}^{40}$K and other rock-forming elements such as Mg can also be outgassed and lost from magma oceans that originate on large planetary embryos and accreting planets. Outgassed elements escape from planetary embryos with masses that are $\ge$\,M${}_{\mathrm{Moon}}$ directly, or due to hydrodynamic drag of escaping H atoms originating from primordial- or steam atmospheres at more massive embryos. We discuss how these processes affect the final elemental composition and ratios such as K/U, Fe/Mg of early planets and their building blocks. Finally, we review modeling efforts that constrain the early evolution of Venus, Earth and Mars by reproducing their measured present day atmospheric ${}^{36}$Ar/${}^{38}$Ar, ${}^{20}$Ne/${}^{22}$Ne noble gas isotope ratios and the role of isotopes on the loss of water and its connection to the redox state on early Mars.

65 pages, 17 figures. This is a preprint of an article published in Space Science Reviews. The final authenticated version can be found online at: https://doi.org/10.1007/s11214-020-00701-x

References in corpus (28)

• The origins and concentrations of water, carbon, nitrogen and noble gases on Earth
• Radar evidence of subglacial liquid water on Mars
• Planetary Candidates Observed by Kepler VI: Planet Sample from Q1-Q16 (47 Months)
• Constraints on the mass of a habitable planet with water of nebular origin
• Atmospheric Mass Loss During Planet Formation: The Importance of Planetesimal Impacts
• Outgassing History and Escape of the Martian Atmosphere and Water Inventory
• Heating efficiency in hydrogen-dominated upper atmospheres
• Evolution of Water Reservoirs on Mars: Constraints from Hydrogen Isotopes in Martian Meteorites
• A giant impact as the likely origin of different twins in the Kepler-107 exoplanet system
• Aeronomical constraints to the minimum mass and maximum radius of hot low-mass planets
• Impact splash chondrule formation during planetesimal recycling
• A Collisional Origin to Earth's Non-chondritic Composition?
• What factors affect the duration and outgassing of the terrestrial magma ocean?
• Extreme hydrodynamic losses of Earth-like atmospheres in the habitable zones of very active stars
• Thermodynamics of Element Volatility and its Application to Planetary Processes
• A Lower Limit of Atmospheric Pressure on Early Mars Inferred from Nitrogen and Argon Isotopic Compositions
• Escape and fractionation of volatiles and noble gases from Mars-sized planetary embryos and growing protoplanets
• Hydrodynamic simulations of captured protoatmospheres around Earth-like planets
• An Overabundance of Low-density Neptune-like Planets
• Extreme hydrodynamic atmospheric loss near the critical thermal escape regime
• Collisional stripping of planetary crusts
• Hydrogen isotopic evidence for early oxidation of silicate Earth
• Formation of Venus, Earth and Mars: Constrained by isotopes
• Anoxic Atmospheres on Mars Driven by Volcanism: Implications for Past Environments and Life
• Transfer, loss and physical processing of water in hit-and-run collisions of planetary embryos
• Impact inducted surface heating by planetesimals on early Mars
• Nitrogen Atmospheres of the Icy Bodies in the Solar System
• Aerosol Constraints on the Atmosphere of the Hot Saturn-mass planet WASP-49b

Cited by in corpus (20)

• Revealing the Mysteries of Venus: The DAVINCI Mission
• Atmospheres of Rocky Exoplanets
• The long-term evolution of the atmosphere of Venus: processes and feedback mechanisms
• Solubility of water in peridotite liquids and the prevalence of steam atmospheres on rocky planets
• Formation of Venus, Earth and Mars: Constrained by isotopes
• The Fundamental Connections Between the Solar System and Exoplanetary Science
• Characterisation of the upper atmospheres of HAT-P-32 b, WASP-69 b, GJ 1214 b, and WASP-76 b through their He I triplet absorption
• Exoplanets with ELT-METIS I: Estimating the direct imaging exoplanet yield around stars within 6.5 parsecs
• Life as the Only Reason for the Existence of N2-O2-Dominated Atmospheres
• Planetary evolution with atmospheric photoevaporation II: Fitting the slope of the radius valley by combining boil-off and XUV-driven escape
• The Exosphere as a Boundary: Origin and Evolution of Airless Bodies in the Inner Solar System and Beyond Including Planets with Silicate Atmospheres
• Nitrogen Atmospheres of the Icy Bodies in the Solar System
• Sublimation of refractory minerals in the gas envelopes of accreting rocky planets
• Non-thermal escape of the Martian CO${}_2$ atmosphere over time: constrained by Ar isotopes
• Modification of the radioactive heat budget of Earth-like exoplanets by the loss of primordial atmospheres
• Mars' atmospheric neon suggests volatile-rich primitive mantle
• The origin of Earth's mantle nitrogen: primordial or early biogeochemical cycling?
• Large Interferometer For Exoplanets (LIFE). XIV. Finding terrestrial protoplanets in the galactic neighborhood
• Takeout and Delivery: Erasing the Dusty Signature of Late-stage Terrestrial Planet Formation
• Evolution and Observable Properties of Rocky Planet Atmospheres