Consequences of planet formation on the stellar composition

Circumstellar disks have an evolving composition due to planet formation processes such as grain growth, planetesimal formation, and disk winds. Therefore, the accretion of disk gas may alter the stellar composition. In order to determine the magnitude of this effect, a key ingredient is the stellar surface convective zone whose thickness determines the dilution of the “planet pollution” signature. Thus, first I will present the thermal evolution of young stellar objects. From stellar evolution calculations, we find that the evolution can deviate from the standard picture depending on accretion heat. Using up-to-date stellar evolution models, we estimate the compositional changes due to planet formation. In this poster, I will focus particularly on the Sun. The Sun has a refractory-poor surface composition compared to solar twins. We find that if the ice-to-rock ratio in the Solar-System planets is less than 0.4, then the anomaly can be originated from the accretion of predominantly volatile elements in the early Solar System due to planet formation. We also find that the signature of planet formation is imprinted in the central region. The central metallicity is enhanced by up to 5%, which is qualitatively in accordance with recent neutrino observations. Therefore, we conclude that accretion including planet formation processes is crucial for a realistic solar model.