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This content will become publicly available on September 3, 2026

Title: The R -process Alliance: Enrichment of r -process Elements in a Simulated Milky Way–like Galaxy
Abstract We study the formation of stars with varying amounts of heavy elements synthesized by the rapid neutron-capture process (r-process) based on our detailed cosmological zoom-in simulation of a Milky Way–like galaxy with anN-body/smoothed particle hydrodynamics code,asura. Most stars with no overabundance inr-process elements, as well as the stronglyr-process-enhanced (RPE)r-II stars ([Eu/Fe] > +0.7), are formed in dwarf galaxies accreted by the Milky Way within the 6 Gyr after the Big Bang. In contrast, over half of the moderately enhancedr-I stars (+0.3 < [Eu/Fe] ≤ +0.7) are formed in the main in situ disk after 6 Gyr. Our results suggest that the fraction ofr-I andr-II stars formed in disrupted dwarf galaxies is larger the higher their [Eu/Fe] is. Accordingly, the most strongly enhancedr-III stars ([Eu/Fe] > +2.0) are formed in accreted components. These results suggest that non-r-process-enhanced stars andr-II stars are mainly formed in low-mass dwarf galaxies that hosted either none or a single neutron star merger, while ther-I stars tend to form in the well-mixed in situ disk. We compare our findings with high-resolution spectroscopic observations of RPE metal-poor stars in the halo and dwarf galaxies, including those collected by theR-Process Alliance. We conclude that observed [Eu/Fe] and [Eu/Mg] ratios can be employed in chemical tagging of the Milky Way’s accretion history.  more » « less
Award ID(s):
2307436
PAR ID:
10637288
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ; ; ;
Publisher / Repository:
The Astrophysical Journal
Date Published:
Journal Name:
The Astrophysical Journal
Volume:
990
Issue:
2
ISSN:
0004-637X
Page Range / eLocation ID:
125
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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