Chemodynamically Characterizing the Jhelum Stellar Stream with APOGEE-2
  We present the kinematic and chemical profiles of red giant stars observed by
the APOGEE-2 survey in the direction of the Jhelum stellar stream, a Milky Way
substructure located in the inner halo of the Milky Way at a distance from the
Sun of $\approx$ 13 kpc. From the six APOGEE-2 Jhelum pointings, we isolate
stars with log($g$) $<$ 3.5, leaving a sample of 289 red giant stars. From this
sample of APOGEE giants, we identified seven stars that are consistent with the
astrometric signal from $Gaia$ DR2 for this stream. Of these seven, one falls
onto the RGB along the same sequence as the Jhelum stars presented by
\cite{ji20}. This new Jhelum member has [Fe/H]=-2.2 and is at the tip of the
red giant branch. By selecting high orbital eccentricity, metal-rich stars, we
identify red giants in our APOGEE sample that are likely associated with the
$Gaia$-Enceladus-Sausage (GES) merger. We compare the abundance profiles of the
Jhelum stars and GES stars and find similar trends in $\alpha$-elements, as
expected for low-metallicity populations. However, we find that the orbits for
GES and Jhelum stars are not generally consistent with a shared origin. The
chemical abundances for the APOGEE Jhelum star and other confirmed members of
the stream are similar to stars in known stellar streams and thus are
consistent with an accreted dwarf galaxy origin for the progenitor of the
stream, although we cannot rule out a globular cluster origin.
