Galactic-Scale Distribution of 10Be and Its Implications for the Early Solar System 10Be/9Be
Abstract
Meteoritic inclusions indicate that the early Solar System contained a substantial abundance of the short-lived radionuclide 10Be. Whether it was inherited from the parent molecular cloud or requires local irradiation or late injection remains debated. Here we present the first three-dimensional simulations of a Milky Way-like disc that follow the multi-phase interstellar medium, cosmic rays (CRs), and the production and transport of 10Be by galactic CRs (GCRs) and in supernova remnants (SNRs). Nearly all 10Be is produced by GCR interactions; SNRs contribute at most about ten percent of the 10Be inherited by newly formed stars. The 10Be/9Be ratio traces the CR energy density, declining smoothly with galactocentric radius, and because stars form where supernovae inject CRs, their natal gas is CR-enriched roughly fivefold relative to the mean interstellar medium, which one-zone estimates miss. Accounting for a possibly higher Galactic star formation rate 4.6 Gyr ago, inheritance of GCR-produced 10Be can then explain the early Solar System's 10Be/9Be in our models, without late injection or local irradiation. Even when GCR-induced 10Be production in dense gas is reduced tenfold, the meteoritic value is reached in the innermost disc and missed by only a factor of a few elsewhere, so the main conclusion is robust to uncertain low-energy GCR penetration. The inferred birth radius of the Sun depends strongly on the CR diffusivity, ranging between 3 and 8 kpc, suggesting that improved modelling of low-energy CR transport could sharpen constraints on the birthplace of the Solar System.
Versions
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BibTeX
@misc{fujimoto2026galacticscale,
title = {{Galactic-Scale Distribution of 10Be and Its Implications for the Early Solar System 10Be/9Be}},
author = {Yusuke Fujimoto and Steven J. Desch and Jiro Shimoda and Shu-ichiro Inutsuka},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.03808},
eprint = {2611.03808},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.03808},
}
RIS
TY - UNPB
TI - Galactic-Scale Distribution of 10Be and Its Implications for the Early Solar System 10Be/9Be
AU - Yusuke Fujimoto
AU - Steven J. Desch
AU - Jiro Shimoda
AU - Shu-ichiro Inutsuka
PY - 2026
DA - 2026/11/02
PB - arXiv
DO - 10.48550/arxiv.2611.03808
UR - https://arxiv.org/abs/2611.03808
AB - Meteoritic inclusions indicate that the early Solar System contained a substantial abundance of the short-lived radionuclide 10Be. Whether it was inherited from the parent molecular cloud or requires local irradiation or late injection remains debated. Here we present the first three-dimensional simulations of a Milky Way-like disc that follow the multi-phase interstellar medium, cosmic rays (CRs), and the production and transport of 10Be by galactic CRs (GCRs) and in supernova remnants (SNRs). Nearly all 10Be is produced by GCR interactions; SNRs contribute at most about ten percent of the 10Be inherited by newly formed stars. The 10Be/9Be ratio traces the CR energy density, declining smoothly with galactocentric radius, and because stars form where supernovae inject CRs, their natal gas is CR-enriched roughly fivefold relative to the mean interstellar medium, which one-zone estimates miss. Accounting for a possibly higher Galactic star formation rate 4.6 Gyr ago, inheritance of GCR-produced 10Be can then explain the early Solar System's 10Be/9Be in our models, without late injection or local irradiation. Even when GCR-induced 10Be production in dense gas is reduced tenfold, the meteoritic value is reached in the innermost disc and missed by only a factor of a few elsewhere, so the main conclusion is robust to uncertain low-energy GCR penetration. The inferred birth radius of the Sun depends strongly on the CR diffusivity, ranging between 3 and 8 kpc, suggesting that improved modelling of low-energy CR transport could sharpen constraints on the birthplace of the Solar System.
ER -