Phases of planetary growth. Top: dust particles grow to pebbles (small dots) and drift toward the star. Icy pebbles that cross the water ice line (dashed line) evaporate their water content and enrich the gas with water vapor. Water vapor that crosses the ice line condenses onto pebbles, increasing their water content. Middle: the core of the planet is formed by pebble accretion while the planet migrates. Depending on the formation path, the core composition can be icy or dry. In the cartoon shown here, the core would be water poor. Bottom: once the planet is heavy enough to reach pebble isolation and form a pressure bump, pebbles are stopped and cannot be accreted by the planet. The planet will then start to accrete gas that is enriched with water vapor. The water content of the disk (in solid or gaseous form) is color coded,where a darker color indicates a higher water content. We restrict ourselves in this cartoon to the water evaporation front, but the same applies for the evaporation of all solids in our model.