Abstract

Contributed Talk - Splinter ExoPlanets

Wednesday, 17 September 2025, 17:27

Simulating the Milky Way's exoplanet population

Chloé Padois, Friedrich Anders, Daniel del Ser
Universitat de Barcelona

In view of the upcoming surveys conducted by PLATO, Roman, HAYDN, and other planet finding missions, we aim to simulate a realistic exoplanet population across different regions of the Milky Way by combining a state-of-the-art cosmological simulation of the Milky Way with exoplanet formation models and observations. In our modelling, we take into account various factors that influence the distribution of exoplanets, such as the host stars' mass, age, metallicity, multiplicity, presence of hot Jupiters, orbital configuration, among others. Focussing first on the solar vicinity, we find only subtle differences in the distributions of non-hosting and planet-hosting single stars. In our simulated solar neighbourhood, 63% of all planets are Earth-like, 36% are Super-Earths/Neptunes, and around 1% are giant planets. These planet sub-populations follow the main trends observed in the present-day exoplanet census, modulo selection effects. A detailed comparison with the census of Kepler exoplanets and candidates shows that, when taking into account the most relevant selection effects, we obtain very similar statistic of exoplanets compared to the observed population. Extending our analysis to other zones of the simulated Milky Way and other galaxies from the same suite of simulations, we find that the relative percentages of Earth-like, Super-Earth/Neptunian, and giant planets do not vary much as long as the simulated galaxy matches the morphology and mass of the Milky Way. We provide the predictions of our volume-complete exoplanet population synthesis in an online repository.