Gemini/GRACES Spectroscopy of Stars in Triangulum II
  The chemical abundance ratios and radial velocities for two stars in the
recently discovered Triangulum II faint dwarf galaxy have been determined from
high resolution, medium signal-to-noise ratio spectra from the Gemini-GRACES
facility. These stars have stellar parameters and metallicities similar to
those derived from their photometry and medium-resolution Ca II triplet
spectra, and supports that Triangulum II has a metallicity spread consistent
with chemical evolution in a dwarf galaxy. The elemental abundances show that
both stars have typical calcium abundances and barium upper limits for their
metallicities, but low magnesium and sodium. This chemical composition
resembles some stars in dwarf galaxies, attributed to inhomogeneous mixing in a
low star formation environment, and/or yields from only a few supernova events.
One of our targets (Star40) has an enhancement in potassium, and resembles some
stars in the unusual outer halo star cluster, NGC 2419. Our other target
(Star46) appears to be a binary based on a change in its radial velocity (Delta
v(rad) = 24.5 +/- 2.1 km/s). This is consistent with variations found in binary
stars in other dwarf galaxies. While this serves as a reminder of the high
binary fraction in these ultra faint dwarf galaxies, this particular object has
had little impact on the previous determination of the velocity dispersion in
Triangulum II.
