摘要：We present high spatial resolution LBTI/NOMIC 9–12 μm images of VYCMa and its massive outflow feature, the Southwest (SW) Clump. Combined with high-resolution imaging from the Hubble Space Telescope (0.4–1μm) and LBT/LMIRCam (1–5μm), we isolate the spectral energy distribution (SED) of the clump from the star itself. Using radiative-transfer code DUSTY, we model both the scattered light from VYCMa and the thermal emission from the dust in the clump to estimate the optical depth, mass, and temperature of the SWClump. The SWClump is optically thick at 8.9 μm with a brightness temperature of ∼200 K. With a dust chemistry of equal parts silicates and metallic iron, as well as assumptions on grain size distribution, we estimate a dust mass of 5.4×10 −5 M e . For a gas-to-dust ratio of 100, this implies a total mass of 5.4×10 −3 M e . Compared to the typical mass-loss rate of VYCMa, the SWClump represents an extreme, localized mass-loss event from 300 yr ago.
