The impact of planet formation scenarios on the composition of rocky exoplanets

In recent years, rocky exoplanets have been discovered using both transit and radial velocity techniques. These planets have short orbital periods and are more easily detected around lower mass stars. Several planets, such as in the TRAPPIST 1 system, are in temperate regions where liquid water may persist. The architecture of the discovered planetary systems has triggered models for their formation history that involve pebble accretion close to the snow line in the proto-planetary disk followed by inward migration, in situ formation inside the snowline, or scenarios in which planets move inwards via dynamical interactions in a gas-poor disk. Such different formation scenarios impact the final bulk composition of the planet. We present the results of parametrized planet formation models that cover these different scenarios, both in terms of the main rock-forming elements (Fe, Mg, Si, Al, Ca) as well as more volatile species such as S and H 2 O (both in the form of water and hydrosilicates). We discuss the resulting range of planet mass-radius relations and compare this to solar system bodies.