Abstract
We presented detailed abundances for a sample of giant stars in the Sagittarius Dwarf Spheroidal Galaxy (Sgr dSph), based on VLT-UVES spectra. The closest known satellite of the Milky Way (MW), Sgr dSph is undergoing tidal disruption while moving along its short period orbit in the Halo and consituting the most prominent case of substructure accretion by the MW. The sampled population appears to be metal rich ([Fe/H] between -0.9 and 0), and shows highly peculiar abundance ratios, with underabundant α elements, deficient Na, Ni, Cu and Zn, and overabundant La, Ce and Nd among others. These abundances hint of a slower star formation rate inside Sgr dSph compared to the one characteristic of the MW disk, with a significant contribution from Sn Ia and AGB yelds. At the same time, they show that Sgr dSph is polluting the Halo with stars which composition is significantly different from the ones encountered in the MW populations. This rules out Sgr dSph as a major Halo building block, but allows to trace populations originally formed inside Sgr dSph and then accreted by the MW.
