| Speaker: | Lorenzo Roberti (Southern National Laboratory, Italy) |
|---|---|
| Title: | The role of massive stars in Galactic and cosmological chemical enrichment from the cosmic dawn |
| Date (JST): | Tue, Apr 14, 2026, 15:30 - 17:00 |
| Place: | Seminar Room A |
| Abstract: |
Massive stars are the primary drivers of the chemical and dynamical evolution of the Universe. From the formation of the first structures during the cosmic dawn to the enrichment of the interstellar medium in the local Universe, these objects act as the fundamental factories of the elements. Understanding their life cycle and explosive death is therefore essential for a comprehensive view of cosmology and Galactic evolution. High-resolution spectroscopy of extremely metal-poor (EMP) stars provides a fossil record of these processes, preserving the chemical signatures of the very first stellar generations. Observational data compiled in major surveys like GALAH and APOGEE, and databases such as JINAbase and SAGA, offer crucial insights into this early enrichment. Parallel to these stellar records, modern high-energy observations, such as the recent X-ray spectroscopy of the Cassiopeia A supernova remnant by the XRISM collaboration, provide a direct view of the material ejected by supernova explosions. Together, these different observational channels offer a multi-epoch perspective on stellar nucleosynthesis across cosmic time. However, interpreting these precise observations remains a significant challenge for theory. Classic core-collapse models often struggle to reproduce the observed chemical patterns, suggesting that our understanding of the physical processes occurring in stellar interiors is still incomplete. This presentation explores how the revision of stellar models and the inclusion of new physical phenomena can drastically alter the predicted nucleosynthetic output. Drawing on recent theoretical and hydrodynamic studies, I will discuss the need for advanced modeling to correctly interpret the increasingly detailed data from both the early Galaxy and modern supernova remnants. |
