The 18th International Symposium on Origin of Matter and Evolution of Galaxies (OMEG18)

Characterizing the Chemical Enrichment Histories of the Milky Way’s Accreted Substructures Using Metal-Poor Stars

Oct 21, 2026, 6:00 PM

3h

Headquarters Building 2F (RIKEN)

Poster Presentation Poster Session

Speaker

Young Sun Lee (Chungnam National University)

Description

We present a chemical and dynamical analysis of 22 metal-poor stars with [Fe/H] < –1.0 selected from Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). High-resolution spectra were obtained with Gemini-N/GRACES and Gemini-S/GHOST, enabling the determination of stellar atmospheric parameters and elemental abundances spanning light, α, iron-peak, and neutron-capture elements. Combining these chemical abundances with Gaia-based dynamical information, we associate the majority of the sample with known Milky Way (MW) substructures, including Gaia-Sausage-Enceladus (GSE), Wukong/LMS-1, and I’itoi. We identify more than half of the sample as r-process-enhanced stars, indicating strong neutron-capture enrichment. Abundance trends of [Mg/Fe], [Eu/Mg], [Ba/Mg], and [Eu/Ba] indicate distinct enrichment histories for each substructure. These results show that metal-poor stars can constrain the nucleosynthetic pathways and progenitor properties of accreted MW systems.