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Abundances of Extreme r-Process Elements in a Sample of CEMP-rs Stars

par Riyas, Muhammed;Karinkuzhi, Drisya ;Van Eck, Sophie
Référence Bulletin de la Société royale des sciences de Liège, 93, 2, page (453-460)
Publication Publié, 2024-07-01

Article révisé par les pairs

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Résumé :

We analyze high-resolution spectra of five carbon-enhanced metal-poor (CEMP) stars acquired using Ultraviolet and Visual Echelle Spectrograph (UVES). Assuming local thermodynamic equilibrium (LTE), we derive the abundances of extreme r-process elements such as Tb, Ho, Tm, and Yb using TURBOSPECTRUM radiative transfer code with MARCS model atmospheres. Four of the program stars have their atmospheric parameters adopted from our previous studies, while for CS 22947-187, we determine the atmospheric parameters (Teff = 5200 K, log g = 1.5, ξ = 1.70 km s-1, and [Fe/H] = -2.55) using the BACCHUS code in semi-automated mode. These stars are already classified as CEMP-rs stars (i.e., carbon-enhanced metal-poor stars with enrichment of elements from both slow and rapid neutron-capture processes), using our new classification criteria for CEMP stars. The derived r-process abundances for our program stars are similar to those for rI and rII stars of similar metallicity.