Modelling of accretion and differentiation of the proto-Earth and its building blocks

拟议的项目将处理有关行星胚胎（地球的组成部分）的热、结构和成分（包括挥发物）演变、一系列巨大撞击之前原地球的吸积及其分化等核心问题。将研究影响熔体偏析和分化成层状结构的化学和物理过程，从而更全面地了解这些过程。申请人以前为半径小于~500公里的天体开发了一个行星胚胎模型，并将加以扩展，以进一步考虑碰撞加热和固态对流的热传输-这一过程与半径增加的天体更为相关。这样一个胚胎的生长及其分化将被考虑，从而产生一个火星大小的原始地球。该模型的另一个重要改进是确定熔化和结晶产物，以更好地限制行星胚胎的成分分层。虽然我们将侧重于数字建模，但将使用基于样本的地外物质（例如HED（howardite，eucrite，diogenite）和岩浆铁陨石）的地球化学矿物学数据以及使命结果（例如黎明使命）的综合来指导和测试模型。

The proposed project will address the central questions regarding the thermal, structural and compositional (including volatiles) evolution of planetary embryos (building blocks of the Earth), the accretion of the proto-Earth prior to the series of giant impacts, as well as its differentiation. Chemical and physical processes influencing the melt segregation and differentiation into a layered structure will be studied resulting in a more comprehensive understanding of these processes. A model of a planetary embryo for bodies smaller than ~500 km in radius was developed previously by the applicant and will be expanded to further consider impact heating and heat transport by solid state convection - processes than become more relevant for bodies with increasing radius. Growth of such an embryo and its differentiation will be considered, resulting in a Mars-sized proto-Earth. A further important enhancement of the model is the determination of the melting and crystallisation products to obtain better constraints on the compositional layering of planetary embryos. Although we will focus on numerical modelling, sample-based geochemical-mineralogical data for extra-terrestrial materials (e.g. HEDs (howardite, eucrite, diogenite) and magmatic iron meteorites) as well as synthesis of mission results (e.g. the Dawn mission) will be used to guide and to test the models.