A faint dust ring beyond the compact disk of Sz 76

We report new ALMA Band 7 high-resolution (about 0.05'') continuum and 12 CO (J=3--2) observations of the disk around the young low-mass star Sz 76. Visibility-plane modeling reveals a previously undetected, faint outer dust ring centered at about 45 au surrounding the compact central disk. Including this low-surface-brightness feature increases the characteristic dust radius from R dust,68 about 7 au to 41 au. Combined with an outer gas extent of R CO,68 about 77 au, the resulting gas-to-dust size ratio decreases from an extreme value of about 11 to about 2, placing Sz 76 in line with typical protoplanetary disks and contradicting a scenario of unimpeded inward radial drift. These results demonstrate that spatial filtering or limited surface-brightness sensitivity can severely underestimate disk sizes, highlighting the necessity of multi-scale observations to properly identify dust traps and accurately constrain disk evolution.