  We present sub-arcsec angular resolution, high-Strehl ratio mid-IR adaptive
optics images of the powerful OH/IR source and cool hypergiant NML Cyg at 8.8,
9.8 and 11.7 um. These images reveal once more the complexity in the dusty
envelope surrounding this star. We spatially resolve the physical structures
(radius ~0.14", ~240 AU adopting a distance of 1.74 kpc) responsible for NML
Cyg's deep 10 um silicate dust absorption feature. We also detect an asymmetric
excess, at separations of ~0.3" to 0.5" (~520 to 870 AU), NW from the star. The
colors of this excess are consistent with thermal emission of hot, optically
thin dust. This excess is oriented in the direction of the Cyg OB2 stellar
association, and is likely due to the disruption of NML Cyg's dusty wind with
the near-UV radiation flux from the massive hot stars within Cyg OB2. This
interaction was predicted in our previous paper (Schuster et al. 2006), to
explain the geometry of an inverted photo-dissociation region observed at
optical wavelengths.
