The Ophiuchus Disk Survey Employing ALMA (ODISEA): Complete Size Distributions for the 100 Brightest Disks Across Multiplicity and SED Classes

The size of a protoplanetary disk is a key factor in star and planet formation. This talk presents an analysis of the size distribution of around 100 bright protoplanetary disks in the Ophiuchus molecular cloud, based on high-resolution ALMA observations at 410 GHz. Disk sizes were measured using the Half Width at Half Maximum and the radius enclosing 68% of the flux. The results show a log-normal size distribution with a mean HWHM of 13 au and a spread of a factor of 2.8.

Disks in close binary systems (separations below 200 au) are significantly smaller, with a mean HWHM of 5 au, suggesting efficient radial drift in these environments. The size distributions of young embedded and more evolved objects are similar, pointing to the presence of pressure bumps early in disk evolution that may slow the inward drift of particles.