The intermediate neutron-capture process in AGB stars

Abstract

The intermediate neutron-capture process is thought to arise when protons are mixed in a convective helium-burning zone. This can happen during the early Thermally-Pulsing (TP) Asymptotic Giant Branch (AGB) phase of low-mass, low-metallicity stars. After discussing the differences between the s- and i-processes in AGB stars, we highlight some critical (n, γ) reactions for i-process nucleosynthesis that may be experimentally constrained by the β-Oslo method. We then compare our s- and i-process nucleosynthesis predictions to the abundances of the Carbon-Enhanced Metal-Poor star HE2258-6358, which shows a composition pattern midway between the s- and r-process.