The mm-colors of a young binary disk system in the Orion Nebula Cluster
  We present new EVLA continuum observations at 7 mm of the 253-1536 binary
disk system in the Orion Nebula Cluster. The measured fluxes were combined with
data in the sub-mm to derive the millimeter spectral index of each individual
disk component. We show how these observations can be used to test the models
of dust evolution and early growth of solids in protoplanetary disks. Our
analysis indicates that the disk with lower density and higher temperature
hosts larger grains than the companion disk. This result is the opposite of
what predicted by the dust evolution models. The models and observational
results can be reconciled if the viscosity $\alpha$-parameter differs by more
than a factor of ten in the two disks, or if the distribution of solids in the
disks is strongly affected by radial motions. This analysis can be applied to
future high-angular resolution observations of young disks with EVLA and ALMA
to provide even stronger observational constraints to the models of dust
evolution in protoplanetary disks.
