Terrestrial Planet Architectures in HZs of Stellar Systems

The final phase of planet formation - when the Earth-like planets are fully formed - can be studied with the help of N-body calculations and collision simulations. For a long time, this scenario could only be depicted in a very simplified way, whereby small bodies (objects up to the size of the moon) were assumed to be virtually massless, so that no mutual forces had to be taken into account. In addition, collisions between two bodies were always regarded as perfect merging of the two objects without analyzing the collision scenario in more detail. Progress in the computer performance and the development of our efficient N-body program (named GANBISS) and the corresponding collision simulation program allow us to study the terrestrial planet formation phase much more realistically in this project. This is because our N-body program allows us to calculate the mutual force effects of tens of thousands of objects, so that the small bodies no longer have to be considered as massless objects in a simplified way. In addition, we will analyze the two-body collisions and assign them to different categories of collisions. The aim of this project is to incorporate the different categories of collisions into the N-body simulations and to perform the terrestrial planet formation scenario in a comprehensive parameter study for different stellar systems (single and binary stars, with and without gas planets present) in order to assess the extent of the errors of previous studies. The detailed analysis of regions that show changes due to perturbations of the gas planets or a stellar companion star with respect to the frequency and type of collisions should provide information about their role in terrestrial planet formation. Based on the improvements in the simulations, the extent to which changes in planetary architecture occur, especially in the so- called Habitable Zone, will be investigated. In addition, this project will analyze the differences between single and binary star systems, demonstrating the role of a stellar companion in terrestrial planet formation. This project will therefore provide important insights for exoplanet research.