Abstract EANA2026-111

Stars and their accretion disks form from the same molecular cloud. Therefore, the composition of a star can serve as a first approximation of the upper limit of its accretion disk’s composition. Using only the host star’s metallicity and the temperature in the disk related to the distance to the star, our model swiftly estimates the composition of planetary building blocks. Unlike more complex models such as GGChem our model prioritizes speed and simplicity and yet, it agrees well with them for C/O ratio < 1. Hence our model provides a fast, accessible first-order approximation that can be easily integrated into other models (e.g. interior structure models). As a first demonstration of the the model’s practical application, we estimated the composition of the TRAPPIST-1 planets. Then, using an interior structure model employing we show that it is possible to predict the core mass fraction and radii for the inner planets, which agree well with the observed values. Here we show the results of parameter study using an improved version of our composition model, now incorporated FastChem for the chemical equilibrium, and a data set from a n-body simulation to illustrate how strongly the composition of terrestrial planets, can differ from that of “Earth-like” planets, and how these compositional variations could affect a planet’s interior structure.