Planet Population, Formation, and Habitability

该项目包括通过与理论预测的比较，对CARMENES巡天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。这是必要的，因为行星的形成过程是如此复杂，以至于模型不能仅仅依赖于第一（物理）原理，而是需要观测指导。特别是来自一个定义明确的、具有已知探测偏差的大观测样本（如CARMENES）的观测约束是至关重要的，因为它们使定量比较成为可能。行星种群合成是一种能够更好地理解行星形成和演化过程的方法。使用全球行星形成和演化模型，结合了联合收割机的许多专门的模型的本质，合成的行星人口产生，然后与观测进行统计比较。为此，我们在过去几年中创建了一个行星人口综合框架。我们的人口综合框架中最重要的元素是全球行星形成模型，它直接预测CARMENES的可观测量（周期和最小质量）。 它基于核心吸积范式，该范式认为巨行星的形成分为两步。首先建立一个临界核心，然后触发气体包层的吸积。这发生在一个不断演化的气体和固体盘中，其他原行星也在其中生长，导致动力学相互作用。盘和原行星交换角动量，意味着轨道迁移发生。CARMENES样本的统计结果对于理论上理解行星如何在M矮星周围形成至关重要。将观测结果与星族合成数据进行比较，将有助于理解诸如低质量恒星周围行星系统的结构是什么等问题。它们与类太阳恒星周围的同类有何不同？是否有可能从行星质量函数中推导出行星盘质量如何随恒星质量变化，从而推导出行星形成所需的物质？有没有可能从半长轴的分布中推导出在这些圆盘中发现的冰线-巨行星形成的首选位置-以及轨道迁移的效率？这对低质量行星上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的大量低质量行星的紧凑系统是否也存在于M矮星周围，可能是一个缩小的版本？

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?