High Precision Astrophysics: Magnetic Activity from Stars to Planets

• Applicant: Professor Dr. Ansgar Reiners
• Subject Area: Astrophysics and Astronomy
• Term: from 2006 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 29408093

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.

• DFG Programme: Independent Junior Research Groups