Dust grain growth in ρ-Ophiuchi protoplanetary disks

摘要

We present new ATCA observations at 3.3mm of 27 young stellar objects in the -Ophyoung cluster. 25 of these sources have been detected. We analyze thesub-millimeter and millimeter SED for a subsample of 17 isolatedclassII protoplanetary disks and derive constraints on the graingrowth and total dust mass in the disk outer regions. All the disks inour sample show a mm slope of the SED which is significantly shallowerthan the one observed for the ISM at these long wavelengths. Thisindicates that 1)classII disks in Ophiuchus host grainsgrown to mm/cm-sizes in their outer regions; 2)formation ofmm/cm-sized pebbles is a fast process and3)a mechanismhalting or slowing down the inward radial drift of solid particles isrequired to explain the data. These findings are consistent withprevious results in other star forming regions. We compare the dustproperties of this sample with those of a uniformly selected sample inTaurus-Auriga and find no statistical evidence of any difference interms of grain growth between the two regions. Finally, in our samplethe mm slope of the SED is not found to correlate with indicators ofgrain growth to micron sizes in the surface layers of the inner disk.Key words: protoplanetary disks - planets and satellites: formation - stars: pre-main sequence