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This paper is part of a larger project in which we systematically study thechemical abundances of Galactic and extragalactic post-asymptotic giant branch(post-AGB) stars. Lead (Pb) is the final product of the s-processnucleosynthesis and is predicted to have large overabundances with respect toother s-process elements in AGB stars of low metallicities. However, Pbabundance studies of enriched post-AGB stars in the Magellanic Clouds show thePb overabundance is not observed. We used high-resolution UVES and HERMESspectra for detailed spectral abundance studies of our sample of 14 Galacticpost-AGB stars. We do not find any clear evidence of Pb overabundances in oursample. Stars with T(eff) > 7500 K do not provide strong constraints on the Pbabundance. We conclude that the discrepancy between theory and observationincreases towards lower metallicities. All objects, except IRAS 17279-1119,confirm the relation between neutron exposure [hs/ls] and third dredge-upefficiency [s/Fe], whereas no relation between metallicity and neutron exposureis detected within the metallicity range of our total sample (-1.4 < [Fe/H] <-0.2). The mild enrichment of IRAS 17279-1119 can probably be attributed to acut-off of the AGB evolution due to binary interactions. To our knowledge, IRAS17279-1119 is the first s-process enhanced Galactic post-AGB star known in abinary system and is a possible precursor of the extrinsic Ba dwarf stars.Lead-rich stars have yet to be found in post-AGB stars. extrinsic Ba dwarfstars. Lead-rich stars are yet to be found in post-AGB stars.

Detailed homogeneous abundance studies of 14 Galactic s-process enriched post-AGB stars: In search of lead (Pb)