Revisiting the dust destruction efficiency of supernovae
  Dust destruction by supernovae is one of the main processes removing dust
from the interstellar medium (ISM). Estimates of the efficiency of this
process, both theoretical and observational, typically assume a shock
propagating into a homogeneous medium, whereas the ISM possesses significant
substructure in reality. We self-consistently model the dust and gas properties
of the shocked ISM in three supernova remnants (SNRs), using X-ray and infrared
(IR) data combined with corresponding emission models. Collisional heating by
gas with properties derived from X-ray observations produces dust temperatures
too high to fit the far-IR fluxes from each SNR. An additional colder dust
component is required, which has a minimum mass several orders of magnitude
larger than that of the warm dust heated by the X-ray emitting gas. Dust-to-gas
mass ratios indicate that the majority of the dust in the X-ray emitting
material has been destroyed, while the fraction of surviving dust in the cold
component is plausibly close to unity. As the cold component makes up virtually
all the total dust mass, destruction timescales based on homogeneous models,
which cannot account for multiple phases of shocked gas and dust, may be
significantly overestimating actual dust destruction efficiencies, and
subsequently underestimating grain lifetimes.
