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28th of August 2020
ATCA observations of protoplanetary disks
by de Gregorio-Monsalvo et al.
De Gregorio-Monsalvo et al. have characterised the emission at centimeter wavelengths in T Chamaleontis, a star surrounded by a transitional protoplanetary disks. Transitional disks are considered to be the missing link between disks surrounding young stars and planetary systems. They are characterized by the presence of gaps in their radial dust distributions, which may be originate from photo-evaporative winds, close stellar companions, planets in formation, and grain growth, among other mechanisms. The team used the Australia Telescope Compact Array (ATCA) to resolve the continuum emission at 7mm and 1.7cm surrounding T Chamaleontis, the first T Tauri star with observational evidence of planetary formation inside a disk gap. The observations at 7mm (above left) reveal a spatially resolved disk with a similar morphology to that observed with ALMA at 850 microns, including the presence of an inner gap. This suggests the emission at 7mm is coming from large dust grains. The 1.7cm observations (above right) barely resolve the disk, and the nature of the emission is more uncertain since two phenomena can contribute to it, both photoevaporative winds driven by high-energy photons from the central star, and a population of "pebbles" with a maximum grain size of at least 3 cm. The white ellipses at bottom left show the synthesized beam size of the observations. The results were presented at the Scientific Meeting of the Spanish Astronomical Society last month.

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