DOI: 10.1002/2017JE005393
Scopus记录号: 2-s2.0-85045203095
论文题名: HCN Production via Impact Ejecta Reentry During the Late Heavy Bombardment
作者: Parkos D. ; Pikus A. ; Alexeenko A. ; Melosh H.J.
刊名: Journal of Geophysical Research: Planets
ISSN: 21699097
出版年: 2018
卷: 123, 期: 4 起始页码: 892
结束页码: 909
语种: 英语
英文关键词: atmospheric chemistry
; HCN
; hypersonic chemosynthesis
; impact ejecta
; Late Heavy Bombardment
; origin of life
英文摘要: Major impact events have shaped the Earth as we know it. The Late Heavy Bombardment is of particular interest because it immediately precedes the first evidence of life. The reentry of impact ejecta creates numerous chemical by-products, including biotic precursors such as HCN. This work examines the production of HCN during the Late Heavy Bombardment in more detail. We stochastically simulate the range of impacts on the early Earth and use models developed from existing studies to predict the corresponding ejecta properties. Using multiphase flow methods and finite-rate equilibrium chemistry, we then find the HCN production due to the resulting atmospheric heating. We use Direct Simulation Monte Carlo to develop a correction factor to account for increased yields due to thermochemical nonequilibrium. We then model 1-D atmospheric turbulent diffusion to find the time accurate transport of HCN to lower altitudes and ultimately surface water. Existing works estimate the necessary HCN molarity threshold to promote polymerization that is 0.01 M. For a mixing depth of 100 m, we find that the Late Heavy Bombardment will produce at least one impact event above this threshold with probability 24.1% for an oxidized atmosphere and 56.3% for a partially reduced atmosphere. For a mixing depth of 10 m, the probability is 79.5% for an oxidized atmosphere and 96.9% for a partially reduced atmosphere. Therefore, Late Heavy Bombardment impact ejecta is likely an HCN source sufficient for polymerization in shallow bodies of water, particularly if the atmosphere were in a partially reduced state. ©2018. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/114129
Appears in Collections: 气候减缓与适应
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作者单位: School of Aeronautics and Astronautics, Purdue University, West Lafayette, IN, United States; Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN, United States; Department of Physics, Purdue University, West Lafayette, IN, United States
Recommended Citation:
Parkos D.,Pikus A.,Alexeenko A.,et al. HCN Production via Impact Ejecta Reentry During the Late Heavy Bombardment[J]. Journal of Geophysical Research: Planets,2018-01-01,123(4)