The [Zn/Fe] – [Fe/H] trend for disk and halo stars

Zn abundances, derived from a model atmosphere analysis of the λ6362.35 Å line, are presented for 44 thin disk, 10 thick disk and 8 halo dwarf stars in the metallicity range . It is found that [Zn/Fe] in thin disk stars shows a slight increasing trend with decreasing metallicity reaching a value at . The thick disk stars in the metallicity range have an average dex, whereas five alpha-poor and Ni-poor halo stars in the same metallicity range have dex. These results indicate that Zn is not an exact tracer of Fe as often assumed in abundance studies of damped Lyman-alpha systems (DLAs). A better understanding of the nucleosynthesis of Zn is needed in order to obtain more detailed information on the past history of star formation in DLAs from e.g. the observed sulphur/zinc ratio.