Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The detailed chemical abundance patterns of accreted halo stars from the
  optical to infrared   Understanding the assembly of our Galaxy requires us to also characterize the
systems that helped build it. In this work, we accomplish this by exploring the
chemistry of accreted halo stars from the Gaia-Enceladus/Gaia-Sausage (GES)
selected in the infrared from the Apache Point Observatory Galactic Evolution
Experiment (APOGEE) Data Release 16. We use high resolution optical spectra for
62 GES stars to measure abundances in 20 elements spanning the $\alpha$,
Fe-peak, light, odd-Z, and notably, the neutron-capture groups of elements to
understand their trends in the context of and in contrast to the Milky Way and
other stellar populations. Using these derived abundances we find that the
optical and the infrared abundances agree to within 0.15 dex except for O, Co,
Na, Cu, and Ce. These stars have enhanced neutron-capture abundance trends
compared to the Milky Way, and their [Eu/Mg] and neutron-capture abundance
ratios (e.g., [Y/Eu], [Ba/Eu], [Zr/Ba], [La/Ba], and [Nd/Ba]) point to
r-process enhancement and a delay in s-process enrichment. Their [$\alpha$/Fe]
trend is lower than the Milky Way trend for [Fe/H]$>$-1.5 dex, similar to
previous studies of GES stars and consistent with the picture that these stars
formed in a system with a lower rate of star formation. This is further
supported by their depleted abundances in Ni, Na, and Cu abundances, again,
similar to previous studies of low-$\alpha$ stars with accreted origins.

25
The categories of this paper are: patt-sol
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
18
The categories of this paper are: econ
10
The categories of this paper are: q-bio