High-resolution ALMA observations of V4046Sgr: a circumbinary disc with a thin ring

Abstract

The nearby V4046 Sgr spectroscopic binary hosts a gas-rich disc known for its wide cavity and dusty ring. We present high resolution ($\sim$20 mas or 1.4 au) ALMA observations of the 1.3mm continuum of V4046 Sgr which, combined with SPHERE--IRDIS polarised images and a well-sampled spectral energy distribution (SED), allow us to propose a physical model using radiative transfer (RT) predictions. The ALMA data reveal a thin ring at a radius of 13.15$\pm$0.42 au (Ring13), with a radial width of 2.46$\pm$0.56 au. Ring13 is surrounded by a $\sim$10 au-wide gap, and it is flanked by a mm-bright outer ring (Ring24) with a sharp inner edge at 24 au. Between 25 and $\sim$35 au the brightness of Ring24 is relatively flat and then breaks into a steep tail that reaches out to $\sim$60 au. In addition, central emission is detected close to the star which we interpret as a tight circumbinary ring made of dust grains with a lower size limit of 0.8 mm at 1.1 au. In order to reproduce the SED, the model also requires an inner ring at $\sim$5 au (Ring5) composed mainly of small dust grains, hiding under the IRDIS coronagraph, and surrounding the inner circumbinary disc. The surprisingly thin Ring13 is nonetheless roughly 10 times wider than its expected vertical extent. The strong near-far disc asymmetry at 1.65 $\mu$m points at a very forward-scattering phase function and requires grain radii of no less than 0.4 $\mu$m.

11 pages, 7 figures

References in corpus (20)

• Protoplanetary Disk Structures in Ophiuchus
• Particle Stirring in Turbulent Gas Disks: Including Orbital Oscillations
• Photoevaporation of protoplanetary discs II: evolutionary models and observable properties
• Dust filtration at gap edges: Implications for the spectral energy distributions of discs with embedded planets
• Measuring turbulent motion in planet-forming disks with ALMA: A detection around DM Tau and non-detections around MWC 480 and V4046 Sgr
• The polarimetric imaging mode of VLT/SPHERE/IRDIS II: Characterization and correction of instrumental polarization effects
• Dust unveils the formation of a mini-Neptune planet in a protoplanetary ring
• CASSIS: The Cornell Atlas of Spitzer/Infrared Spectrograph Sources. II. High-resolution observations
• Exploring dust around HD142527 down to 0.025" / 4au using SPHERE/ZIMPOL
• Including Dust Coagulation in Hydrodynamic Models of Protoplanetary Disks: Dust Evolution in the Vicinity of a Jupiter-mass Planet
• An ALMA survey of DCN/H${}^{13}$CN and DCO${}^{+}$/H${}^{13}$CO${}^{+}$ in protoplanetary disks
• Disks Around T Tauri Stars with SPHERE (DARTTS-S) II: Twenty-one new polarimetric images of young stellar disks
• Calibrated griz magnitudes of Tycho stars: All-sky photometric calibration using bright stars
• The dispersal of protoplanetary disks around binary stars
• Scattered light mapping of protoplanetary disks
• Nitrogen Fractionation in Protoplanetary Disks from the H13CN/HC15N Ratio
• Scattered Light from Dust in the Cavity of the V4046 Sgr Transition Disk
• Cooling in the shade of warped transition disks
• Long live the disk: lifetimes of protoplanetary disks in hierarchical triple star systems and a possible explanation for HD 98800 B
• Constraints on a Putative Planet Sculpting the V4046 Sagittarii Circumbinary Disk

Cited by in corpus (9)

• exoALMA IV: Substructures, Asymmetries, and the Faint Outer Disk in Continuum Emission
• The Giant Accreting Protoplanet Survey (GAPlanetS) -- Results from a Six Year Campaign to Image Accreting Protoplanets
• The ALMA view of MP Mus (PDS 66): a protoplanetary disk with no visible gaps down to 4 au scales
• Observed polarized scattered light phase functions of planet-forming disks
• Constraining giant planet formation with synthetic ALMA images of the Solar System's natal protoplanetary disk
• ALMA's view of the M-dwarf GSC 07396-00759's edge-on debris disc: AU Mic's coeval twin
• Radial variations in nitrogen, carbon, and hydrogen fractionation in the PDS 70 planet-hosting disk
• The ALMA survey to Resolve exoKuiper belt Substructures (ARKS) VIII: A dust arc and non-Keplerian gas kinematics in HD 121617
• The influence of tight binaries on proto-planetary disk masses