In this poster we present a detailed chemical analysis of the RV Tauri star of low intrinsic metallicity , V453 Oph ( [ Fe/H ] = -2.2 ) , which shows a mild but clear s-process surface overabundance .
This result is strengthened by a relative analysis to the RV Tauri star DS Aqr of similar metal deficiency ( [ Fe/H ] = -1.6 ) , but without such s-process enrichment .
A remarkable result is that the s-process enrichment of V453 Oph is not accompanied by a measurable C enhancement .
To explain the surface abundances observed in V453 Oph , two nucleosynthesis models are considered .
The first model assumes the partial mixing of protons during the radiative interpulse phase while the second scenario is based on the possible production of s-process elements within the flash-driven convective pulse only .
Both models can give a satisfactory explanation for the s-process enrichment of V453 Oph , but not the simultaneous low C-abundance observed .