Speaker: Boquan Erwin Chen
Institution: Australian National University
Title: The Milky Way as a Prototypical Disk Galaxy: Galactic Archeology and Chemical Evolution in Context
Abstract: The chemical evolution of the Milky Way has long been regarded as uniquely complex, epitomized by its distinct dual [α/Fe] sequences. This perceived intricacy has driven interpretations reliant on multi-phase formation models, such as the two-infall framework. Yet, breakthroughs in Galactic archeology—powered by Gaia astrometry and large-scale spectroscopic surveys—are challenging this narrative, revealing that the Milky Way’s chemical evolution may align closely with processes observed in typical disk galaxies. In this talk, I will present a unified, physically motivated model of chemical evolution that reframes the Milky Way not as an outlier but as a galactic archetype. We demonstrate that key observables—including the radial metallicity gradient, stellar metallicity distribution, and age-abundance trends—can be simultaneously reproduced under a coherent framework consistent with generic disk galaxy formation. By reconciling these features without invoking exceptional mechanisms, our results suggest that the Milky Way’s apparent complexity stems from its detailed observational record rather than atypical evolutionary pathways. Furthermore, the archetypal nature of the Milky Way may extend to its very origins, implying that its early assembly followed pathways common to disk galaxies. Nevertheless, stellar-level observations of the M31 Andromeda galaxy and Large Magellanic Cloud (LMC) highlight the diversity of galactic chemical evolution. This renewed perspective positions our Galaxy as a critical benchmark for deciphering the universal processes shaping disk galaxies across cosmic time, offering insights that bridge local precision to extragalactic contexts.
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