Cosmic dust fluxes in the atmospheres of Earth, Mars, and Venus
Cosmic dust fluxes in the atmospheres of Earth, Mars, and Venus
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DOI：
10.1016/j.icarus.2019.113395
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发表时间：
2020-01-01
期刊：
影响因子：
3.2
通讯作者：
Plane, John M. C.
中科院分区：
文献类型：
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作者：
Carrillo-Sanchez, Juan Diego;Carlos Gomez-Martin, Juan;Plane, John M. C.
宇宙尘埃的消融将一系列金属注入行星的高层大气。此外，进入大气层后幸存下来的尘埃颗粒可能是行星表面有机物质的重要来源。在这项研究中，金属和有机物的贡献，从三个宇宙尘埃源-彗星族彗星（JFCs），小行星带（AST），哈雷型彗星（HTCs）-地球，火星和金星的大气相结合的化学烧蚀模型（CABMOD）与黄道云模型（ZoDy）的估计。ZoDy提供了JFC、AST和HTC粒子的质量、速度和辐射分布。JFC被证明是所有三个大气层中的主要质量贡献者（金星68%，地球70%，火星52%），为金星，地球和火星提供的总输入质量分别为31 +/- 18 t d（-1），28 +/- 16 t d（-1）和2 +/- 1 t d（-1）。AST粒子的质量贡献随着日心距离的增加而增加（金星为6%，地球为9%，火星为14%）。CABMOD中的一种新的多相处理，在流星烧蚀模拟器中进行了实验测试，实现了从硅酸盐熔体和Fe-Ni金属域量化大气烧蚀。在地球、火星和金星上的Fe：Ni烧蚀通量比预计接近它们的CI-18，与地球电离层中Fe+：Ni+ = 20（-8）（+13）的质谱测量结果一致。相比之下，激光雷达对地球中性原子的测量结果表明Fe：Ni = 38 +/- 11，而MAVEN航天器上的中性气体和离子质谱仪在火星上的观测结果表明Fe+：Ni+ = 11。考虑到火星上宇宙尘埃粒子的平均进入速度较慢，火星上未熔化粒子的吸积率占总输入质量的60%，其中很大一部分（22%）未达到有机热解温度（类似于900 K），导致14 kg d（-1）的完整碳通量。这比以前的估计要少得多。
The ablation of cosmic dust injects a range of metals into planetary upper atmospheres. In addition, dust particles which survive atmospheric entry can be an important source of organic material at a planetary surface. In this study the contribution of metals and organics from three cosmic dust sources - Jupiter-Family comets (JFCs), the Asteroid belt (AST), and Halley-Type comets (HTCs) - to the atmospheres of Earth, Mars and Venus is estimated by combining a Chemical Ablation Model (CABMOD) with a Zodiacal Cloud Model (ZoDy). ZoDy provides the mass, velocity, and radiant distributions for JFC, AST, and HTC particles. JFCs are shown to be the main mass contributor in all three atmospheres (68% for Venus, 70% Earth, and 52% for Mars), providing a total input mass for Venus, Earth and Mars of 31 +/- 18 t d(-1), 28 +/- 16 t d(-1) and 2 +/- 1 t d(-1), respectively. The mass contribution of AST particles increases with heliocentric distance (6% for Venus, 9% for Earth, and 14% for Mars). A novel multiphase treatment in CABMOD, tested experimentally in a Meteoric Ablation Simulator, is implemented to quantify atmospheric ablation from both the silicate melt and Fe-Ni metal domains. The ratio of Fe:Ni ablation fluxes at Earth, Mars and Venus are predicted to be close to their CI chondritic ratio of 18, in agreement with mass spectrometric measurements of Fe+:Ni+ = 20(-8)(+13) in the terrestrial ionosphere. In contrast, lidar measurements of the neutral atoms at Earth indicate Fe:Ni = 38 +/- 11, and observations by the Neutral Gas and Ion Mass Spectrometer on the MAVEN spacecraft at Mars indicate Fe+:Ni+ = . Given the slower average entry velocity of cosmic dust particles at Mars, the accretion rate of unmelted particles in Mars represents 60% of the total input mass, of which a significant fraction of the total unmelted mass (22%) does not reach an organic pyrolysis temperature (similar to 900 K), leading to a flux of intact carbon of 14 kg d(-1). This is significantly smaller than previous estimates.