Abundances for stars in Plaut's window

We also measure lithium for a super Li-rich RGB star. The abundances were determined by spectrum synthesis of high-resolution (R{approx}25000), high signal-to-noise (S/N ~ 50-100/pixel) spectra obtained with the Blanco 4m telescope and Hydra multifiber spectrograph.

For the bulge RGB stars, we find a general increase in the [Na/Fe] and [Na/Al] ratios with increasing metallicity, and a similar decrease in [La/Fe] and [Nd/Fe]. Additionally, the [Al/Fe] and [Eu/Fe] abundance trends almost identically follow those of the {alpha}-elements, and the [Zr/Fe] ratios exhibit relatively little change with [Fe/H]. The consistently low [La/Eu] ratios of the RGB stars indicate that at least a majority of bulge stars formed rapidly (<~1Gyr) and before the main s-process could become a significant pollution source.