Elemental depletions in the Magellanic Clouds and the evolution of
  depletions with metallicity
  We present a study of the composition of gas and dust in the Large and Small
Magellanic Clouds (LMC and SMC, together -- the MCs) as measured by UV
absorption spectroscopy. We have measured P II and Fe II along 85 sightlines
toward the MCs using archival FUSE observations. For 16 of those sightlines, we
have measured Si II, Cr II, and Zn II from new HST COS observations. We have
combined these measurements with H I and H$_2$ column densities and reference
stellar abundances from the literature to derive gas-phase abundances,
depletions, and gas-to-dust ratios (GDRs). 80 of our 84 P measurements and 13
of our 16 Zn measurements are depleted by more than 0.1 decades, suggesting
that P and Zn abundances are not accurate metallicity indicators at and above
the metallicity of the SMC. The maximum P and Zn depletions are the same in the
MW, LMC, and SMC. Si, Cr, and Fe are systematically less depleted in the SMC
than in the MW or LMC. The minimum Si depletion in the SMC is consistent with
zero. Our depletion-derived GDRs broadly agree with GDRs from the literature.
The GDR varies from location to location within a galaxy by a factor of up to 2
in the LMC and up to 5 in the SMC. This variation is evidence of dust
destruction and/or growth in the diffuse neutral phase of the interstellar
medium.
