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 \pm 2.1 km s ^ { -1 } ) .
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 .