Abundances of Extreme r-Process Elements in a Sample of CEMP-rs Stars
Muhammed Riyas,
Department of Physics, University of Calicut, Kerala-673635, India
Drisya Karinkuzhi,
Department of Physics, University of Calicut, Kerala-673635, India and Institut d’Astronomie et d’Astrophysique, Université Libre de Bruxelles, ULB, Campus Plaine C.P. 226, Boulevard du Triomphe, 1050 Bruxelles, Belgium. Corresponding author: drdrisyak@uoc.ac.in
Sophie van Eck,
Institut d’Astronomie et d’Astrophysique, Université Libre de Bruxelles, ULB, Campus Plaine C.P. 226, Boulevard du Triomphe, 1050 Bruxelles, Belgium. Corresponding author: svaneck@astro.ulb.ac.be
Abstract
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.
Keywords : Nuclear reactions, nucleosynthesis, abundances, Stars: AGB and post-AGB, binaries: spectroscopic
Pour citer cet article
Muhammed Riyas, Drisya Karinkuzhi & Sophie van Eck, «Abundances of Extreme r-Process Elements in a Sample of CEMP-rs Stars», Bulletin de la Société Royale des Sciences de Liège [En ligne], Volume 93 - Année 2024, No 2 - Proceeedings of the 3rd BINA Workshop on the Scientific Potential of the Indo-Belgian Cooperation, 453-460 URL : http://popups.ulg.be/0037-9565/index.php?id=11747.
