The intermediate neutron capture process

Context. Carbon-enhanced metal-poor (CEMP) r/s-stars show surface-abundance distributions characteristic of the so-called intermediate neutron capture process (i-process) nucleosynthesis. We previously showed that ingestion protons in convective helium-burning region a low-mass low-metallicity star can explain surface abundance distribution observed CEMP r/s stars relatively well. Such an i-process requires detailed reaction network calculations involving hundreds nuclei for which rates have not yet been determined experimentally. Aims. investigate nuclear physics uncertainties affecting during asymptotic giant branch (AGB) phase by propagating theoretical radiative cross sections, as well 13 C( ? , n ) 16 O rate, and estimating their impact on distribution. Methods. used STAREVOL code to follow evolution 1 M ? [Fe/H] = ? 2.5 model proton event occurring at beginning AGB phase. In computation, we adopt 1160 species coupled transport processes different sets sections consistently calculated with TALYS code. Results. It is found considering systematic various ingredients rates, elemental abundances are typically predicted within ±0.4 dex. The 56 ? Z 59 spectroscopically relevant heavy-s elements Ba-La-Ce-Pr r-dominated Eu element remain unaffected uncertainties. contrast, inclusion direct contribution impacts neutron-rich A ? 45, 100, 160, 200 regions, production 45 65–70 elements. Uncertainties photon strength function also overabundance factors 0.2–0.4 Nuclear level densities tend affect predictions mainly 74 79 regions. associated neutron-producing unknown ? -decay low overall enrichment. Conclusions. nucleosynthesis early remains sensitive uncertainties, substantially still sections. Improved descriptions based shell or experimental constraints from ( d p reactions could help decrease estimated rates. Similarly, functions densities, example through Oslo method, 100 160 would increase predictive power present simulations.