| Name: | Muhammed Riyas A |
| Affiliation: | University of Calicut |
| Conference ID: | ASI2025_216 |
| Title: | Dissecting r-Process Elemental Abundance Trends in CEMP Subclasses |
| Authors: | Muhammed Riyas 1, Drisya Karinkuzhi 1,2, Sophie van Eck 2 |
| Authors Affiliation: | 1 Department of Physics, University of Calicut, Kerala–673635, India.
2 Institut d’Astronomie et d’Astrophysique, Université Libre de Bruxelles, ULB, Campus Plaine
C. P. 226, Boulevard du Triomphe, 1050 Bruxelles, Belgium. |
| Mode of Presentation: | Oral |
| Abstract Category: | Stars, Interstellar Medium, and Astrochemistry in Milky Way |
| Abstract: | Metal-poor stars formed in the early universe reveal crucial information about early chemical evolution. Many of these stars, especially in the Milky Way's halo, are enriched in carbon ([C/Fe] > 1.0) and are known as Carbon-Enhanced Metal-Poor (CEMP) stars. CEMP stars are categorized into CEMP-r, CEMP-s, and CEMP-rs types based on their heavy element enrichment via the slow (s-process) and rapid (r-process) neutron capture processes. The s-process occurs in low- to intermediate-mass stars, while the r-process likely occurs in neutron star mergers or specific supernovae. However, the origin of CEMP stars enriched in both s- and r-process elements (CEMP-r/s stars) remains uncertain. Increasing evidence suggests that the intermediate neutron capture process (i-process) may explain this dual enrichment by producing r-process elements in conditions between those of the s- and r-processes. These, studies focus mainly on elements like Eu, Gd, and Dy, while extreme r-process elements, such as Tb, Tm, Yb, Ho, Ta, and Th, remain unexplored due to their sensitive lines falling in the near-UV range. In our recent analysis we derive the abundances of extreme r-process elements in a samle of CEMP-rs stars using their bluer spectra acquired using UVES spectrograph connected to 8m VLT. Our analysis indicates that extreme r-process elements can also be produced by the i-process. We confirm our results by comparing observed abundances with nucleosynthetic predictions from low-metallicity, low-mass asymptotic giant branch (AGB) stars, a potential sites for the origin of CEMP-s and CEMP-rs stars (Karinkuzhi et al. 2021; Choplin et al. 2021), after including extended networks for both s-process (Goriely & Siess 2018) and i-process (Choplin et al. 2021) reactions. |
