Constraints on a Putative Planet Sculpting the V4046 Sagittarii Circumbinary Disk

Abstract

We analyze the highest-resolution millimeter continuum and near-infrared (NIR) scattered-light images presented to date of the circumbinary disk orbiting V4046 Sgr, a ∼20-Myr-old actively accreting, close binary T Tauri star system located a mere 72.4 pc from Earth. We observed the disk with the Atacama Large Millimeter/submillimeter Array (ALMA) at 870 μ m during Cycle 4, and we analyze these data in conjunction with archival NIR ( H band) polarimetric images obtained with SPHERE/IRDIS on the ESO Very Large Telescope. At 0.″3 (20 au) resolution, the 870 μ m image reveals a marginally resolved ring that peaks at ∼32 au and has an extension of ∼90 au. We infer a lower limit on a dust mass of ∼60.0 M ⊕ within the 870 μ m ring, and confirm that the ring is well aligned with the larger -scale gaseous disk. A second, inner dust ring is also tentatively detected in the ALMA observations; its position appears coincident with the inner (∼14 au radius) ring detected in scattered light. Using synthetic 870 μ m and H -band images obtained from disk–planet interaction simulations, we attempt to constrain the mass of the putative planet orbiting at 20 au. Our trials suggest that a circumbinary Jovian-mass planet may be responsible for generating the dust ring and gap structures detected within the disk. We discuss the longevity of the gas-rich disk orbiting V4046 Sgr in the context of the binary nature of the system.