On The Metal-poor non-Sagittarius Globular Cluster NGC 5053: Orbit, Mg,
  Al, and Si
  Metal-poor globular clusters (GCs) show intriguing Al-Mg and Si-Al
correlations, which are important clues to decipher the multiple population
phenomenon. NGC 5053 is one of the most metal-poor GCs, and has been suggested
to be associated with the Sagittarius dwarf galaxy (Sgr), due to its similar
location and radial velocity with one of the Sgr arms. In this work, we
simulate the orbit of NGC 5053, and argue against the connection between Sgr
and NGC 5053. Meanwhile, Mg, Al, and Si spectral lines, which are difficult to
detect in the optical spectra, have been detected in the near-infrared APOGEE
spectra. We use three different sets of stellar parameters and codes to derive
the Mg, Al, and Si abundances, and we always see a large Al variation, and a
substantial Si enhancement. Comparing with other metal-poor GCs, we suggest
metallicity may not be the only parameter that controls the multiple
populations.
