The Formation of Planetary Proto-Atmospheres

行星原始大气层的形成

• 批准号: 347185604
• 负责人: Professor Dr. Rolf Kuiper
• 金额: --
• 依托单位: Abteilung Computational Physics
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/347185604?language=en
• 关键词: Formation; Planetary; Proto; Atmospheres

Context: During their formation, proto-planets become massive enough to gravitationally bind gas from the disks they are born in. For giant planets such as Jupiter, the rocky or icy core becomes so massive that it triggers a runaway accretion of gas. Smaller planets such as Neptune, Earth, and super-Earths instead are only able to bind a limited amount of gas. Hence, the physical details of gas accretion in the disk-embedded phase yields a distinctive attribute of the observed planetary distribution.Methods: The formation and early evolution of planetary proto-atmospheres, embedded in their natal disk, shall be investigated using state-of-the-art radiation-hydrodynamical modeling. We will include both - the hydrodynamic as well as the thermodynamic - effects in two- and three-dimensional simulations. Moreover, conducting these simulations in a local frame in planeto-centric spherical coordinates with the planet at the origin of the grid, allows us to resolve the physics of the atmospheric build-up in very high resolution. Initial and boundary conditions for the local frame, representing the large-scale disk flow, will be extracted from preceding global disk simulations, performed in spherical coordinates with the host star at the origin of the grid.Aims: We will extract the atmospheric mass, its rotation profile, and the radiative cooling as well as the gas replenishing timescale as a function of the core, the disk, and the optical properties of the surrounding gas and dust. From that, we investigate under which condition the forming atmosphere approaches a steady state or quasi-stationary system. Additionally, we can specifically test the hypothesis, whether the thermal heat stored in the core and/or the asymmetric structure of the gas flow prevents the atmospheres of super-Earths from collapsing. Resume: The hydrodynamics and thermodynamics of planetary proto-atmospheres will be investigated in direct high-resolution modeling of their formation and early evolution. Following a local approach allows us to determine the small-scale physics in unprecedented detail. The research outcome will shed light on the formation and stability of super-Earth atmospheres.

背景：在它们的形成过程中，原行星的质量变得足够大，足以通过引力束缚它们所诞生的圆盘中的气体。对于像木星这样的巨行星，岩石或冰冷的核心变得如此巨大，以至于引发了气体的失控吸积。相反，海王星、地球和超级地球等较小的行星只能结合有限数量的气体。因此，盘嵌入相中气体吸积的物理细节产生了观测到的行星分布的独特属性。方法：应使用最先进的辐射流体动力学模型来研究嵌入其诞生盘中的行星原大气层的形成和早期演化。我们将在二维和三维模拟中包含流体动力学和热力学效应。此外，在以行星为中心的球面坐标系中以行星为网格原点的局部坐标系中进行这些模拟，使我们能够以非常高的分辨率解析大气形成的物理原理。代表大规模圆盘流的局部坐标系的初始和边界条件将从之前的全局圆盘模拟中提取，这些模拟是在网格原点与主星的球面坐标中进行的。目标：我们将提取大气质量、其旋转轮廓、辐射冷却以及气体补充时间尺度，作为核心、圆盘以及周围气体和尘埃的光学特性的函数。由此，我们研究在什么条件下形成的气氛接近稳态或准稳态系统。此外，我们可以具体测试这个假设，即存储在核心中的热量和/或气流的不对称结构是否可以防止超级地球的大气层崩溃。简历：行星原大气的流体动力学和热力学将通过对其形成和早期演化的直接高分辨率建模进行研究。遵循局部方法使我们能够以前所未有的细节确定小尺度物理。研究成果将揭示超级地球大气层的形成和稳定性。