High Precision Astrophysics: Magnetic Activity from Stars to Planets

磁场活动支配着类太阳恒星的性质，它是太阳辐照度变化的原因，也是更好地理解太阳与气候的联系的基础。磁性活动在类太阳和较冷的恒星中随处可见，在类行星的恒星下天体，即所谓的棕矮星中也可以发现。太阳、恒星和恒星下的磁性活动是在具有非常不同的大气和表面结构的物理相关物体中发生的相同过程的表现。在提议的艾美诺特小组中，我们将系统地研究类太阳恒星和连接太阳和行星之间差距的恒星下天体的磁活动、大气和表面结构。我们的目标是提供恒星和恒星下环境中磁活动的全面图像，并在此背景下了解太阳活动。具体地说，我们将在恒星和棕矮星中进行高精度的光谱实验，以研究它们的大气层、表面性质和磁活动的直接驱动因素。我们将准备分析来自卫星飞行任务的高精度光度数据，并将收集和分析约10万颗类似太阳的恒星的数据。为了更好地了解物理条件，特别是在非常冷的物体中，我们将通过观测来确定基本的分子常数，这些基本分子常数很难从实验室测量中获得，但可以从高精度的天体物理学中推导出来。

Magnetic activity governs the properties of sun-like stars, it is the reason for solar irradiance variations and fundamental for a better understanding of the Sun-climate connection. Magnetic activity is ubiquitously observed in sun-like and cooler stars, and it is found in planet-like substellar objects, so-called brown dwarfs. Solar, stellar and substellar magnetic activity are manifestations of the same processes occurring in physically related objects that possess very different atmospheres and surface structure. In the proposed Emmy Noether group, we will systematically investigate magnetic activity, atmospheres and surface structure in sun-like stars and substellar objects that bridge the gap between the Sun and planets. Our goal is to provide a comprehensive picture of magnetic activity in stellar and substellar environments, and to understand solar activity in this context. Specifically, we will carry out high precision spectroscopic experiments in stars and brown dwarfs to investigate their atmospheres, surface properties and immediate drivers of magnetic activity. We will prepare the analysis of high precision photometric data from satellite missions, and we will collect and analyze such data for some 100 000 sun-like stars. To better understand physical conditions especially in very cool objects, we will observationally determine fundamental molecular constants that are difficult to obtain from laboratory measurements, but can be deduced from high precision astrophysics.