星子碰撞增生过程中的同位素分馏研究进展

Advances in Isotopic Fractionation in Planetesimal Collisional Accretion Processes

理解行星的初始物质组成以及其形成过程对于研究太阳系的形成和演化、地球的生物宜居性有着重要的意义。星子碰撞吸积是类地行星形成过程中的一个重要阶段,该阶段影响行星整体的元素和同位素组成。中等挥发性元素及其同位素是研究这一过程的有效工具,因为它们对示踪撞击过程中的高温蒸发和降温凝聚等过程较为灵敏。笔者系统统计了球粒陨石和来自不同天体(地球、月球、火星和灶神星)的陨石样品部分元素及同位素测试数据,讨论了不同天体的中等挥发性元素及其同位素的特征和导致同位素分馏的主要因素,并探讨其对行星初始物质组成和形成过程的指示意义。星子、行星胚胎等天体的碰撞过程可能极大地限制了类地行星的挥发性元素含量。

Understanding the initial material composition and formation process of planets is of great significance for studying the formation and evolution of the solar system and the biological habitability of the Earth.Planetesimal collision and accretion is an important stage in the formation of terrestrial planets,which affects the elemental and isotopic composition of the planets.Moderately volatile elements and their isotopes are effective tools for studying this process,because they are sensitive to tracing the processes of high-temperature evaporation and cooling condensation during the impact.This paper systematically summarizes the test data of some elements and isotopes of chondrites and meteorite samples from different celestial bodies(including Earth,Moon,Mars and Vesta),discusses the characteristics and main factors causing isotopic fractionation of moderately volatile elements and their isotopes of different celestial bodies,and explores their implications for the initial material composition and formation process of planets.The impact process of planetesimals,planetary embryos and other celestial bodies may greatly limit the volatile element content of terrestrial planets.