Evolution of the Earth's Atmosphere during Late Veneer Accretion

Recent advances in our understanding of the dynamical history of the Solar system have altered the inferred bombardment history of the Earth during accretion of the Late Veneer, after the Moon-forming impact. We investigate how the bombardment by planetesimals left-over from the terrestrial planet r...

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Bibliographic Details
Published in:arXiv.org 2020-10
Main Authors: Sinclair, Catriona A, Wyatt, Mark C, Morbidelli, Alessandro, Nesvorny, David
Format: Article
Language:English
Subjects:
Asteroids
Atmosphere
Atmospheres
Atmospheric models
Bombardment
Comets
Composition
Deposition
Dynamic models
Earth
Evolution
Impactors
Moon
Planet formation
Planetary atmospheres
Primitive Earth atmosphere
Solar system
Terrestrial planets
Veneers
Volatile compounds
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Summary:Recent advances in our understanding of the dynamical history of the Solar system have altered the inferred bombardment history of the Earth during accretion of the Late Veneer, after the Moon-forming impact. We investigate how the bombardment by planetesimals left-over from the terrestrial planet region after terrestrial planet formation, as well as asteroids and comets, affects the evolution of Earth's early atmosphere. We develop a new statistical code of stochastic bombardment for atmosphere evolution, combining prescriptions for atmosphere loss and volatile delivery derived from hydrodynamic simulations and theory with results from dynamical modelling of realistic populations of impactors. We find that for an initially Earth-like atmosphere impacts cause moderate atmospheric erosion with stochastic delivery of large asteroids giving substantial growth (\(\times 10\)) in a few \(\%\) of cases. The exact change in atmosphere mass is inherently stochastic and dependent on the dynamics of the left-over planetesimals. We also consider the dependence on unknowns including the impactor volatile content, finding that the atmosphere is typically completely stripped by especially dry left-over planetesimals (\(
ISSN:2331-8422
DOI:10.48550/arxiv.2010.06254