Isotopic variation of non-carbonaceous meteorites caused by dust leakage across the Jovian gap in the solar nebula

TL;DR

This study models how dust leakage across Jupiter's gap in the early solar nebula affected the isotopic compositions of non-carbonaceous and carbonaceous meteorites, explaining their isotopic differences and age correlations.

Contribution

It introduces a new model simulating dust size evolution and isotopic anomalies, demonstrating how dust leakage influences meteorite isotopic signatures and their formation timing.

Findings

Dust leakage causes isotopic contamination in meteorite reservoirs.

Model results align with observed isotopic values of NC and CC meteorites.

Positive correlation between isotopic anomalies and meteorite age is explained.

Abstract

High-precision isotopic measurements of meteorites revealed that they are classified into non-carbonaceous (NC) and carbonaceous (CC) meteorites. One plausible scenario for achieving this grouping is the early formation of Jupiter because massive planets can create gaps that suppress the mixing of dust across the gap in protoplanetary disks. However, the efficiency of this suppression by the gaps depends on dust size and the strength of turbulent diffusion, allowing some fraction of the dust particles to leak across the Jovian gap. In this study, we investigate how isotopic ratios of NC and CC meteorites are varied by the dust leaking across the Jovian gap in the solar nebula. To do this, we constructed a model to simulate the evolution of the dust size distribution and the $^{54}$Cr-isotopic anomaly $\varepsilon^{54}$Cr in isotopically heterogeneous disks with Jupiter. Assuming that the parent bodies of NC and CC meteorites are formed in two dust-concentrated locations inside and outside Jupiter's orbit, referred to as the NC reservoir and CC reservoir, we derive the temporal variation of $\varepsilon^{54}$Cr at the NC and CC reservoir. Our results indicate that substantial contamination of CC materials occurs at the NC reservoir in the fiducial run. Nevertheless, the values of $\varepsilon^{54}$Cr at the NC reservoir and the CC reservoir in the run are still consistent with those of NC and CC meteorites formed around 2 Myrs after the formation of calcium-aluminum-rich inclusions. Moreover, this dust leakage causes a positive correlation between the $\varepsilon^{54}$Cr value of NC meteorites and the accretion ages of their parent bodies.