Forming Jupiter, Saturn, Uranus and Neptune in Few Million Years by Core Accretion

TL;DR

This paper demonstrates that under certain conditions, the core accretion model can explain the rapid formation of all four giant planets within a few million years, aligning with observational disk lifetimes.

Contribution

The study shows that a specific size distribution of planetesimals enables the core accretion model to form Jupiter, Saturn, Uranus, and Neptune quickly enough, addressing previous time-scale challenges.

Findings

Giant planets can form within a few million years under certain planetesimal size distributions.

Planets end up with core masses consistent with current estimates.

Formation times are compatible with observed protoplanetary disk lifetimes.

Abstract

Giant planet formation process is still not completely understood. The current most accepted paradigm, the core instability model, explains several observed properties of the solar system's giant planets but, to date, has faced difficulties to account for a formation time shorter than the observational estimates of protoplanetary disks' lifetimes, especially for the cases of Uranus and Neptune. In the context of this model, and considering a recently proposed primordial solar system orbital structure, we performed numerical calculations of giant planet formation. Our results show that if accreted planetesimals follow a size distribution in which most of the mass lies in 30-100 meter sized bodies, Jupiter, Saturn, Uranus and Neptune may have formed according to the nucleated instability scenario. The formation of each planet occurs within the time constraints and they end up with core masses in good agreement with present estimations.