Rapid formation of Gas Giant Planets via Collisional Coagulation from Dust Grains to Planetary Cores

TL;DR

This study presents comprehensive simulations demonstrating that gas giant planets can rapidly form from dust to planetary cores within a few hundred thousand years through collisional coagulation, addressing previous challenges like radial drift and core growth timescales.

Contribution

The paper introduces full-scale simulations of dust to planet formation, highlighting the role of realistic porosity and pebble accretion in enabling rapid gas giant formation within typical protoplanetary disks.

Findings

Gas giants form within 0.2-0.4 million years.

Formation occurs at 2-7 au, consistent with observed systems.

Pebble accretion suppresses radial drift, facilitating core growth.

Abstract

Gas-giant planets, such as Jupiter, Saturn and massive exoplanets, were formed via the gas accretion onto the solid cores each with a mass of roughly ten Earth masses. However, rapid radial migration due to disk-planet interaction prevents the formation of such massive cores via planetesimal accretion. Comparably rapid core growth via pebble accretion requires very massive protoplanetary disks because most pebbles fall into the central star. Although planetesimal formation, planetary migration, and gas-giant core formation have been studied with much effort, the full evolution path from dust to planets are still uncertain. Here we report the result of full simulations for collisional evolution from dust to planets in a whole disk. Dust growth with realistic porosity allows the formation of icy planetesimals in the inner disk (> 10 au), while pebbles formed in the outer disk drift to the inner disk and there grow to planetesimals. The growth of those pebbles to planetesimals suppresses their radial drift and supplies small planetesimals sustainably in the vicinity of cores. This enables rapid formation of sufficiently massive planetary cores within 0.2-0.4 million years, prior to the planetary migration. Our models shows first gas giants form at 2-7 au in rather common protoplanetary disks, in agreement with the exoplanet and solar systems.