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The Triangulum--Andromeda (TriAnd) overdensity is a distant structure of theMilky Way located in the second Galactic quadrant well below the Galacticplane. Since its discovery, its nature has been under discussion, whether itcould be old perturbations of the Galactic disk or the remains of a disruptedformer dwarf galaxy. In this study, we investigate the kinematics and chemicalcomposition in 13 stars selected as TriAnd candidates from 2MASS photometry.The sample was observed using the GRACES high-resolution spectrograph attachedto the Gemini North telescope. Based on radial velocities obtained from thespectra and the astrometric data from GAIA, three different kinematic criteriawere used to classify our sample stars as belonging to the TriAnd overdensity.The TriAnd confirmed members in our sample span a range in metallicities,including two metal-poor stars ([Fe/H] $\sim$ -1.3 dex). We show that theadopted kinematical classification also chemically segregates TriAnd andnon-TriAnd members of our sample, indicating a unique chemical pattern of theTriAnd stars. Our results indicate different chemical patterns for the [Na/Fe],[Al/Fe], [Ba/Fe], and [Eu/Fe] ratios in the TriAnd stars when compared to thechemical pattern of the local disk; the paucity of studies chemicallycharacterizing the outer disk population of the Milky Way is the main obstaclein establishing that the TriAnd population is chemically similar to field starsin the outer disk. But TriAnd chemical pattern is reminiscent of that found inouter disk open clusters, although the latter are significantly more metal-richthan TriAnd.

Triangulum-Andromeda overdensity: a region with a complex stellar population