Planet Population, Formation, and Habitability

该项目通过与理论预测的比较，对卡门调查的观测结果进行理论解释和分析。通过这种方式，它得出了行星形成和演化理论的关键观测约束条件。这是必要的，因为行星形成过程如此复杂，以至于模型不能仅依靠第一(物理)原理，而需要观测指导。特别是来自定义明确的、具有已知探测偏差的大观测样本(如卡门)的观测约束是至关重要的，因为它们使定量比较成为可能。使更好地理解行星形成和演化过程成为可能的一种方法是行星种群合成。使用结合了许多专门模型的精华的全球行星形成和演化模型，生成了行星的合成种群，然后将其与观测数据进行统计比较。为此，我们在过去几年创建了一个行星人口合成框架。我们人口合成框架中最重要的元素是全球行星形成模型，该模型直接预测卡门的可观测数量(周期和最小质量)。它基于核心吸积范式，该范式认为巨型行星是在一个两步过程中形成的。首先建立一个关键的核心，然后触发气体包层的吸积。这发生在气体和固体的演化圆盘中，其他原行星也在其中生长，导致了动力学相互作用。圆盘和原行星交换角矩，这意味着发生了轨道迁移。卡门样本的统计结果对于在理论上理解行星如何在M矮星周围形成的进展是至关重要的。将观测结果与人口合成数据进行比较，将有助于理解以下问题：围绕低质量恒星的行星系统是什么结构？它们与类太阳恒星周围的同类恒星有何不同？有没有可能从行星质量函数中推导出行星盘质量随恒星质量的变化，从而得出行星形成所需的物质？能否从半长轴的分布中得出冰线--巨行星形成的首选位置--在这些圆盘中的位置，以及轨道迁移的效率如何？这对小质量行星上的水的可用性意味着什么？开普勒卫星在类太阳恒星周围发现了数量非常多的几个小质量行星组成的致密系统，它们是否也存在于M矮星周围，可能是缩小的版本？

This project encompasses the theoretical interpretation and analysis of the observational results of the CARMENES survey through comparisons with theoretical predictions. In this way it derives key observational constraints for planet formation and evolution theory. This is necessary because the planet formation process is so complex that models cannot rely on first (physical) principles alone, but need observational guidance. In particular observational constraints from a well-defined, large observational sample with a known detection bias (as CARMENES) are of paramount importance since they make quantitative comparisons possible.A method that makes it possible to better understand the planetary formation and evolution process is planetary population synthesis. Using global planet formation and evolution models that combine the essence of many specialized models, synthetic populations of planets are generated and then compared statistically with observations. For this, we have created in the last years a framework for planet population synthesis. The most important element of our population synthesis framework is the global planet formation model, which directly predicts CARMENES' observable quantities (period and minimum mass). It is based on the core accretion paradigm, which states that giant planets form in a two-step process. First a critical core is built, which then triggers the accretion of the gaseous envelope. This happens in an evolving disk of gas and solids in which also other protoplanets grow, leading to dynamical interactions. The disk and the protoplanet exchange angular moment, meaning that orbital migration occurs.The statistical results of the CARMENES sample are central for the progress in the theoretical understanding how planets form around M-dwarfs. The comparison of the observational results with the population synthesis data will help to understand questions like: what are the architectures of planetary systems around low-mass stars? How do they differ from their counterparts around solar-like stars? Is it possible to derive from the planetary mass function how the disk masses change with stellar mass, and therefore the material available for planet formation? Is it possible to derive from the distribution of semimajor axes where the iceline - the preferred location of giant planet formation - is found in these disks, and how efficient orbital migration is? What does this mean for the availability of water on low-mass planets? Do the compact systems of several low-mass planets found in very high numbers by the Kepler satellite around solar-like stars also exist around M-dwarfs, potentially in a scaled-down version?