tokens: We acknowledge the SVT team at ESO HQ for their help during the preparation of the OBs and the VLT team for conducting the observations. We thank C. P. Dullemond, G. Lesur, M. Min, and M. Tauras for fruitful discussions, and the referee for providing useful comments. M.B. acknowledges financial support from “Programme National de Physique Stellaire” (PNPS) of CNRS/INSU, France. C.G. was supported under the NASA Origins of Solar Systems program on NNG13PB64P. T.B. acknowledges support from NASA Origins of Solar Systems grant NNX12AJ04G.
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