High-res. spectroscopy for 26 halo KIC stars

After applying theoretically motivated corrections to the seismic scaling relations, we obtain an average mass of 0.97+/-0.03M_{sun}_ for our sample of halo stars. Although this maps into an age of ~7Gyr, significantly younger than independent age estimates of the Milky Way stellar halo, we considered this apparently young age to be due to the overestimation of stellar mass in the scaling relations.

There is no significant mass dispersion among lower red giant branch stars (logg>2), which constrains the relative age dispersion to <18%, corresponding to <2Gyr. The precise chemical abundances allow us to separate the stars with [Fe/H]{>}-1.7 into two [Mg/Fe] groups. While the [{alpha}/Fe] and [Eu/Mg] ratios are different between the two subsamples, [s/Eu], where s stands for Ba, La, Ce, and Nd, does not show a significant difference.