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arXiv · 2304.00156

The Chemodynamical Nature of the Triangulum-Andromeda Overdensity

Yuri Abuchaim·Hélio D. Perottoni·Silvia Rossi·Guilherme Limberg·Angeles Pérez-Villegas·Rafael M. Santucci·Vinicius M. Placco·João V. Sales-Silva·Friedrich Anders·Helio J. Rocha-Pinto
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Abstract

We present a chemodynamical study of the Triangulum-Andromeda overdensity (TriAnd) employing a sample of 31 candidate stars observed with the GRACES high-resolution ($R$=40,000) spectrograph at the Gemini North (8.1 m) telescope. TriAnd is a stellar substructure found toward the outer disk of the Milky Way, located at $R_{\rm GC}\sim 18$ kpc from the Sun, toward Galactic latitude $b \sim 25${\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 \textit{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.

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Yuri Abuchaim, Hélio D. Perottoni, Silvia Rossi, Guilherme Limberg, Angeles Pérez-Villegas, Rafael M. Santucci, Vinicius M. Placco, João V. Sales-Silva, Friedrich Anders, Helio J. Rocha-Pinto. 2023-03-31. The Chemodynamical Nature of the Triangulum-Andromeda Overdensity. https://doi.org/10.3847/1538-4357%2Facc9bc

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