Isolating Dust and Free-Free Emission in ONC Proplyds with ALMA Band 3 Observations

Nicholas P Ballering

Rich clusters are the typical sites of star and planet formation in the Galaxy, and the Orion Nebula Cluster (ONC) is the most readily observable rich cluster. We present ALMA Band 3 (3 mm) observations of the inner 1.5 x 1.5 arcminutes of the ONC at high sensitivity (~30 uJy) and spatial resolution (60 mas). We detect many sources, including compact protoplanetary disks and extended emission from proplyds?disks in the process of being photoevaporated by the external radiation field. At 3 mm, these observations are sensitive to both dust thermal emission and free-free emission from ionized gas. We analyze the proplyd images in conjunction with previous measurements at 850 um (from ALMA) and cm wavelengths (from the VLA) to isolate the dust from the free-free. We measure the disk sizes, dust masses, spectral indices, and photoevaporative mass loss rates to further our understanding of planet formation in a high-radiation cluster environment.