Numerical Simulations of Supernova Dust Destruction. II. Metal-Enriched
  Ejecta Knots
  Following our previous work, we investigate through hydrodynamic simulations
the destruction of newly-formed dust grains by sputtering in the reverse shocks
of supernova remnants. Using an idealized setup of a planar shock impacting a
dense, spherical clump, we implant a population of Lagrangian particles into
the clump to represent a distribution of dust grains in size and composition.
We vary the relative velocity between the reverse shock and ejecta clump to
explore the effects of shock-heating and cloud compression. Because supernova
ejecta will be metal-enriched, we consider gas metallicities from Z/Zsun = 1 to
100 and their influence on cooling properties of the cloud and the thermal
sputtering rates of embedded dust grains. We post-process the simulation output
to calculate grain sputtering for a variety of species and size distributions.
In the metallicity regime considered in this paper, the balance between
increased radiative cooling and increased grain erosion depends on the impact
velocity of the reverse shock. For slow shocks (velocity less than or equal to
3000 km/s), the amount of dust destruction is comparable across metallicities,
or in some cases is decreased with increased metallicity. For higher shock
velocities (velocity greater than or equal to 5000 km/s), an increase in
metallicity from Z/Zsun = 10 to 100 can lead to an additional 24% destruction
of the initial dust mass. While the total dust destruction varies widely across
grain species and simulation parameters, our most extreme cases result in
complete destruction for some grain species and only 44% dust mass survival for
the most robust species. These survival rates are important in understanding
how early supernovae contribute to the observed dust masses in high-redshift
galaxies.
