Natural separation of two primordial planetary reservoirs in an expanding solar protoplanetary disk

TL;DR

This paper proposes that the separation of two primordial planetary reservoirs in the early solar system was due to the viscous expansion of the protoplanetary disk, rather than Jupiter acting as a strict barrier, explaining isotopic differences in meteorites.

Contribution

It introduces a new model where disk expansion delays the arrival of carbonaceous material in the inner solar system, challenging the Jupiter barrier hypothesis.

Findings

Jupiter likely formed beyond 10 AU.

The viscous expansion of the disk delayed CC material influx.

The model explains isotopic dichotomy in meteorites.

Abstract

Meteorites display an isotopic composition dichotomy between non-carbonaceous (NC) and carbonaceous (CC) groups, indicating that planetesimal formation in the solar protoplanetary disk occurred in two distinct reservoirs. The prevailing view is that a rapidly formed Jupiter acted as a barrier between these reservoirs. We show a fundamental inconsistency in this model: if Jupiter is an efficient blocker of drifting pebbles, then the interior NC reservoir is depleted by radial drift within a few hundred thousand years. If Jupiter lets material pass it, then the two reservoirs will be mixed. Instead, we demonstrate that the arrival of the CC pebbles in the inner disk is delayed for several million years by the viscous expansion of the protoplanetary disk. Our results support that Jupiter formed in the outer disk (>10 AU) and allowed a considerable amount of CC material to pass it and become accreted by the terrestrial planets.