Relatore
Descrizione
Carbon-Enhanced Metal-Poor (CEMP) stars are fundamental tracers for Galactic archaeology, providing a unique window into the nucleosynthetic processes that shaped the early Milky Way. A key challenge in this field is the interpretation of CEMP-rs stars, whose chemical patterns are often attributed to the intermediate ($i$-) process. However, distinguishing between an $i$-process origin and a combined $s+r$ enrichment requires high-precision abundance determinations and advanced spectral modelling. Here we present a comprehensive re-analysis of the benchmark CEMP-rs star TYC 6044-714-1, using new high-resolution, high-S/N UVES spectra. These observational results were compared with the latest AGB nucleosynthesis predictions to investigate the physical consistency of the proposed enrichment scenarios. Our results indicate that TYC 6044-714-1 is an in-situ halo star, likely pre-enriched by a standard $r$-process event. We find that a pure $s+r$ model provides the best overall reproduction of the heavy-element distribution and Ba isotopic ratios. While models incorporating the $i$-process can improve the fit for specific elements, they require physically extreme conditions and yield Ba isotopic fractions that are inconsistent with the 4934 Å resonance line. We conclude that the $s+r$ scenario remains the most robust explanation for this star, highlighting the critical role of high-precision spectroscopy in refining our understanding of early Galactic chemical evolution.
| Sessione | La Galassia e il Gruppo Locale |
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