2025ApJ...992...56T

The intermediate neutron-capture process (i-process) may occur during proton ingestion events, with post-asymptotic giant branch (AGB) stars considered among its potential astrophysical sites. This study selected the post-AGB star IRAS 14325-6428, which is enriched in both Ba ([Ba/Fe] = 2.08) and Eu ([Eu/Fe] = 1.25), to investigate its elemental abundance pattern and the odd-isotope ratio of Ba. The atmospheric parameters of the star, T_eff = 7900 ± 80 K, log g = 1.2 ± 0.10, [Fe/H]= -0.75 ± 0.05, and ξ_t = 5.8 ± 0.20 km s^–1, were derived, taking into account non-local thermodynamic equilibrium effects. We match the observed elemental abundances with the pattern of abundance distributions of various astrophysical processes and find that the s- and r-processes alone or together cannot explain the heavy element enrichment mechanism in this star. The observed odd-isotope ratio of barium is f_odd,Ba = 0.25 ± 0.08, suggesting that the heavy elements in post-AGB star IRAS 14325-6428 may be contaminated by the i-process.