The origin of dust extinction curves with or without the 2175 A bump in
  galaxies: The case of the Magellanic Clouds
  The Large and Small Magellanic Clouds (LMC and SMC, respectively) are
observed to have characteristic dust extinction curves that are quite different
from those of the Galaxy (e.g., strength of the 2175 A bump). Although the dust
composition and size distribution of the Magellanic Clouds (MCs) that can
self-consistently explain their observed extinction curves have been already
proposed, it remain unclear whether and how the required dust properties can be
achieved in the formation histories of the MCs. We therefore investigate the
time evolution of the dust properties of the MCs and thereby derive their
extinction curves using one-zone chemical evolution models with formation and
evolution of small and large silicate and carbonaceous dust grains and dusty
winds associated with starburst events. We find that the observed SMC
extinction curve without a conspicuous 2175 A bump can be reproduced well by
our SMC model, if the small carbon grains can be selectively lost through the
dust wind during the latest starburst about 0.2 Gyr ago. We also find that the
LMC extinction curve with a weak 2175 A bump can be reproduced by our LMC model
with less efficient removal of dust through dust wind. We discuss possible
physical reasons for different dust wind efficiencies between silicate and
graphite and among galaxies.
