Can Dust Injected by SNe Explain the NIR-MIR Excess in Young Massive
  Stellar Clusters?
  We present a physically-motivated model involving the different processes
affecting supernova dust grains as they are incorporated into the thermalized
medium within young massive star clusters. The model is used to explain the
near- to mid-infrared (NIR-MIR) excess found in such clusters and usually
modeled as a blackbody with temperature $\sim (400-1000)$ K. In our approach,
dust grains are efficiently produced in the clumpy ejecta of core-collapse
supernovae, fragmented into small pieces ($\lesssim 0.05$ $\mu$m) as they are
incorporated into the hot and dense ISM, heated via frequent collisions with
electrons and the absorption of energetic photons. Grains with small sizes can
more easily acquire the high temperatures ($\sim 1000$ K) required to produce a
NIR-MIR excess with respect to the emission of foreground PAHs and starlight.
However, the extreme conditions inside young massive clusters make difficult
for these small grains to have a persistent manifestation at NIR-MIR
wavelengths as they are destroyed by efficient thermal sputtering.
Nevertheless, the chances for a persistent manifestation are increased by
taking into account that small grains become increasingly transparent to their
impinging ions as their size decreases. For an individual SN event, we find
that the NIR-MIR excess last longer if the time required to incorporate all the
grains into the thermalized medium is also longer, and in some cases,
comparable to the characteristic interval between supernova explosions. Our
models, can successfully explain the near-infrared excesses found in the star
clusters observed in M33 (Rela\~no et al. 2016) assuming a low heating
efficiency and mass-loading. In this scenario, the presence of the NIR-MIR
excess is an indication of efficient dust production in SNe and its subsequent
destruction
