Abstract

Planet formation models rely on initial conditions for which the observed, evolved population of disks is not representative. Therefore, a retrieval approach can be useful for constraining e.g. the initial disk mass and radius – but also the viscous alpha parameter. A first attempt reveals inconsistencies indicating that our simple viscous disk and dust evolution model needs adjustments. The planetary mass and composition distribution from a planetary population synthesis approach based on such initial conditions, can be used in long-term planetary evolution models instead of an arbitrary choice. In particular, formation models with planetary migration predict a large number of water-rich planets inconsistent with the standard mass-loss explanation for the observed radius valley. We show that such a coupled formation and evolution model reproduces observations if water is mixed with H/He as (supercritical) vapor and the valley separates rocky from water-rich planets.