The (sub-)millimeter SED of protoplanetary disks in the outskirts of the Orion nebula cluster

We present the sub-mm/mm SED for a sample of eight young circumstellar disks in the outer regions of the Orion nebula cluster (ONC). New observations were carried out at 2.9 mm with the CARMA array and for one disk, 216-0939, at 3.3 and 6.8 mm with ATCA. By combining these new millimeter data with literature measurements at sub-millimeter wavelengths we investigate grain growth and measure the dust mass in protoplanetary disks in the ONC. These data provide evidence for dust grain growth to at least millimeter-sizes for the first time in a high-mass star-forming region. The obtained range in sub-mm/mm spectral index, namely 1.5-3.2, indicates that for disks in the outskirts of the ONC (projected distance from the cluster center between about 0.4 pc and 1.5 pc) grain growth to mm sizes occurs in the same manner as disks in regions where only low-mass stars form. Finally, in our sample three disks are more massive than about 0.05 M-circle dot, confirming that massive disks are present in the outer regions of the Orion nebula.