Grain Destruction in a Supernova Remnant Shock Wave
  Dust grains are sputtered away in the hot gas behind shock fronts in
supernova remnants, gradually enriching the gas phase with refractory elements.
We have measured emission in C IV $\lambda$1550 from C atoms sputtered from
dust in the gas behind a non-radiative shock wave in the northern Cygnus Loop.
Overall, the intensity observed behind the shock agrees approximately with
predictions from model calculations that match the Spitzer 24 micron and the
X-ray intensity profiles. Thus these observations confirm the overall picture
of dust destruction in SNR shocks and the sputtering rates used in models.
However, there is a discrepancy in that the CIV intensity 10" behind the shock
is too high compared to the intensities at the shock and 25" behind it.
Variations in the density, hydrogen neutral fraction and the dust properties
over parsec scales in the pre-shock medium limit our ability to test dust
destruction models in detail.
