The first metal enrichment in the Universe was made by a supernova explosion of a population III star. Second generation stars were formed from the mixture of the pristine gas and the supernova ejecta. Metal-poor stars were survivors of second-generation stars in the Galactic halo. Their abundance pattern records the metal abundance at their formation and tell us the chemical evolution in the...
Very metal-poor (VMP) stars record the signatures of early accreted galaxies, making them essential tools for unraveling the early Galaxy formation. Meanwhile, understanding the origin of VMP stars requires comprehensive studies of their chemical compositions and kinematics, which are currently lacking. We cluster the dynamically tagged groups for ~6000 VMP stars and conduct a chemodynamical...
In the paradigm of hierarchical structure formation, we expect that numerous low-mass galaxies had been accreted to the Milky Way and leave their stellar debris throughout the stellar halo, which can be identified through searching for stellar substructures of similar orbital properties among metal-poor stars. However, only with the help of analyzing the detailed elemental abundances of their...
The satellite galaxies of the Milky Way and other galaxies are important probes of the early evolution and nucleosynthesis in the cosmos. As such, an understanding of their formation and evolution is crucial in any study of the origin and evolution of matter. In this regard, there is a decades-old dilemma in our understanding of dwarf-galaxy evolution known as the Disks of Satellites (DoS)...
