A faint dust ring beyond the compact disk of Sz 76
Year: 2026
Type: article
Abstract: We report new ALMA Band 7 high-resolution (∼0.05″) continuum and 12 CO ( J = 3–2) observations of the disk around the young low-mass star Sz 76. Visibility plane modeling have revealed a previously undetected, faint outer dust ring centered at ∼45 au surrounding the compact central disk. Including this low-surface-brightness feature increases the characteristic dust radius from R dust,68 ≈ 7 au to 41 au. Combined with an outer gas extent of R CO,68 ≈ 77 au, the resulting gas-to-dust size ratio decreases from an extreme value of ∼11 to ∼2, setting 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.
Source: Astronomy and Astrophysics
Institutions: European Southern Observatory, European Southern Observatory, Universidad Nacional Autónoma de México, University of Milan, Konkoly Observatory, HUN-REN Research Centre for Astronomy and Earth Sciences, Astronomical Observatory of Capodimonte, National Institute for Astrophysics, Thüringer Landessternwarte Tautenburg, Boston University, University of Hawaiʻi at Mānoa, Chinese Academy of Sciences, Chinese Academy of Science South America Center for Astronomy, National Astronomical Observatories, University of Valparaíso
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
OpenAlex ID: W7220361171