(Proposal ID) S13A-023 (PI) Vargas, Luis (Proposal Title) Constraining the Role of Dwarf Galaxies in Building the Milky Way Outer Halo (Abstract) The formation of the Milky Way stellar halo is not well constrained to date. The large number of dwarf spheroidal galaxies (dSphs) orbiting the Milky Way suggested that halo stars were acquired via the accretion of satellite systems, in agreement with hierarchical structure formation. However, dSphs and local halo stars have discrepant chemical abundances patterns, against the expectation from the accretion mechanism. A major limitation to a meaningful halo-dSph comparison is that all available halo samples are composed of local stars (d_helio <~5 kpc). In contrast, accreted satellites are expected to contribute stars mostly to R_GC >~ 25 kpc. To constrain the contribution of dSphs to the formation of the halo, we propose high-resolution (R~50,000) Subaru/HDS observations of ~18-24, distant halo red giants (R_GC ~ 25-60 kpc), in order to measure their detailed chemical abundances. Reliable distance estimates for targets are obtained by combining spectroscopic stellar parameters from low-resolution SDSS/SEGUE spectra with absolute magnitudes from theoretical isochrones. The targets are not kinematically biased. Our sample will constitute the first dataset of chemical abundances of non-local halo stars.