Dinesh P. Shenoy, Terry J. Jones, Roberta M. Humphreys, Massimo Marengo, Jarron M. Leisenring, Matthew J. Nelson, John C. Wilson, Michael F. Skrutskie, Philip M. Hinz, William F. Hoffmann, Vanessa Bailey, Andrew Skemer, Timothy Rodigas, Vidhya Vaitheeswaran
We present adaptive optics images of the extreme red supergiant VY Canis Majoris in the Ks, L' and M bands (2.15 to 4.8 micron) made with LMIRCam on the Large Binocular Telescope (LBT). The peculiar "Southwest Clump" previously imaged from 1 to 2.2 micron appears prominently in all three filters. We rule out thermal emission as a source of its brightness, which we attribute to scattering alone. We model its brightness as optically thick scattering from silicate dust grains using typical size distributions. We find a lower limit mass of approximately 5E-03 Msun in this single feature. 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.
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http://arxiv.org/abs/1305.6912
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