Rapid Formation of Gas-giant Planets via Collisional Coagulation from Dust Grains to Planetary Cores. II. Dependence on Pebble Bulk Density and Disk Temperature

TL;DR

This study uses dust-to-planet simulations to show that gas-giant planetary cores can rapidly form within several hundred thousand years from non-porous pebbles, primarily through collisional coagulation and planetesimal accretion.

Contribution

It demonstrates that non-porous pebbles can also lead to quick gas-giant core formation, expanding the understanding of planet formation mechanisms.

Findings

Gas-giant cores form within several 10^5 years.

Non-porous pebbles can produce planetesimals via collisional coagulation.

Core formation occurs over a wider region (5-10 au) with non-porous pebbles.

Abstract

Thanks to ``dust-to-planet'' simulations (DTPSs), which treat the collisional evolution directly from dust to giant-planet cores in a protoplanetary disk, we showed that giant-planet cores are formed in $\lesssim 10\,$au in several $10^5$ years, because porous pebbles grow into planetesimals via collisions prior to drift in 10 au (Kobayashi & Tanaka 2021, Paper I).However, such porous pebbles are unlikely to reproduce the polarized millimeter wavelength light observed from protoplanetary disks. We thus investigate gas-giant core formation with non-porous pebbles via DTPSs. Even non-porous bodies can grow into planetesimals and massive cores to be gas giants are also formed in several $10^5$ years. The rapid core formation is mainly via the accretion of planetesimals produced by collisional coagulation of pebbles drifting from the outer disk. The formation mechanism is similar to the case with porous pebbles, while core formation occurs in a wider region (5 - 10 au) than that with porous pebbles.