2013AJ....146...90S

We present adaptive optics images of the extreme red supergiant VY Canis Majoris in the K_s, L', and M bands (2.15-4.8 µm) made with LMIRCam on the Large Binocular Telescope. The peculiar "Southwest Clump" previously imaged from 1 to 2.2 µm appears prominently in all three filters. We find its brightness is due almost entirely to scattering, with the contribution of thermal emission limited to at most 25%. We model its brightness as optically thick scattering from silicate dust grains using typical size distributions. We find a lower limit mass for this single feature of 5x10^–3 M_☉ to 2.5x10^–2 M_☉ depending on the assumed gas-to-dust ratio. The presence of the Clump as a distinct feature with no apparent counterpart on the other side of the star is suggestive of an ejection event from a localized region of the star and is consistent with VY CMa's history of asymmetric high-mass-loss events.