High-resolution sp. obs. of stars in TriAnd

TriAnd is a stellar substructure found toward the outer disk of the Milky Way, located at R_GC_~18kpc from the Sun, toward Galactic latitude b~25{deg}. Most stars in our sample have dynamical properties compatible with a disk stellar population.

In addition, by applying an eccentricity cut, we are able to detect a stellar contamination that seems to be consistent with an accreted population. In chemical abundance space, the majority of our TriAnd candidates are similar to the outer thin-disk population, suggesting that the overdensity has an in situ origin. Finally, the found accreted halo interlopers spatially overlapping with TriAnd should explain the historical discussion of the overdensity's nature due to its complex chemical patterns.