Sequential giant planet formation initiated by disc substructure

Abstract

Context. Planet formation models are necessary to understand the origins of diverse planetary systems. Circumstellar disc substructures have been proposed as preferred locations of planet formation, but a complete formation scenario has not been covered by a single model so far. Aims. We aim to study the formation of giant planets facilitated by disc substructure and starting with sub-micron-sized dust. Methods. We connect dust coagulation and drift, planetesimal formation, N-body gravity, pebble accretion, planet migration, planetary gas accretion, and gap opening in one consistent modelling framework. Results. We find rapid formation of multiple gas giants from the initial disc substructure. The migration trap near the substructure allows for the formation of cold gas giants. A new pressure maximum is created at the outer edge of the planetary gap, which triggers the next generation of planet formation resulting in a compact chain of giant planets. A high planet formation efficiency is achieved, as the first gas giants are effective at preventing dust from drifting further inwards, which preserves material for planet formation. Conclusions. Sequential planet formation is a promising framework to explain the formation of chains of gas and ice giants.