High-resolution ALMA observations of compact discs in the wide-binary system Sz 65 and Sz 66

Abstract

Substructures in disc density are ubiquitous in the bright extended discs that are observed with high resolution. These substructures are intimately linked to the physical mechanisms driving planet formation and disc evolution. Surveys of star-forming regions find that most discs are in fact compact, less luminous, and do not exhibit these same substructures. It remains unclear whether compact discs also have similar substructures or if they are featureless. This suggests that different planet formation and disc evolution mechanisms operate in these discs. We investigated evidence of substructure within two compact discs around the stars Sz 65 and Sz 66 using high angular resolution observations with ALMA at 1.3 mm. The two stars form a wide-binary system with 6.36 arcsec separation. The continuum observations achieve a synthesised beam major axis of 0.026 arcsec, equivalent to about 4.0 au, enabling a search for substructure on these spatial scales and a characterisation of the gas and dust disc sizes with high precision. We analysed the data in the image plane through an analysis of reconstructed images, as well as in the uv plane by modelling the visibilities and by an analysis of the 12CO emission line. Comparisons were made with high-resolution observations of compact discs and radially extended discs. We find evidence of substructure in the dust distribution of Sz 65, namely a shallow gap centred at approximately 20 au, with an emission ring exterior to it. Ninety percent of the measured continuum flux is found within 27 au, and the distance for 12CO is 142 au. The observations show that Sz 66 is very compact: 90 per cent of the continuum flux is contained within 16 au, and 48 au for the gas. While the overall prevalence and diversity of substructure in compact discs relative to larger discs is yet to be determined, we find evidence that substructures can exist in compact discs.

References in corpus (34)

• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• X-Shooter spectroscopy of young stellar objects in Lupus: Accretion properties of class II and transitional objects
• A Steeper than Linear Disk Mass-Stellar Mass Scaling Relation
• Ring shaped dust accumulation in transition disks
• Gaps, Rings, and Non-Axisymmetric Structures in Protoplanetary Disks - From Simulations to ALMA Observations
• Spiral Density Waves in a Young Protoplanetary Disk
• Evidence of fast pebble growth near condensation fronts in the HL Tau protoplanetary disk
• Chemical enrichment of giant planets and discs due to pebble drift
• Dust flow in gas disks in the presence of embedded planets
• Multiple Disk Gaps and Rings Generated by a Single Super-Earth
• Different dust and gas radial extents in protoplanetary disks: consistent models of grain growth and CO emission
• The newborn planet population emerging from ring-like structures in discs
• The Disk Substructures at High Angular Resolution Project (DSHARP): IV. Characterizing substructures and interactions in disks around multiple star systems
• Planet-forming material in a protoplanetary disc: the interplay between chemical evolution and pebble drift
• Magnetic Flux Concentration and Zonal Flows in Magnetorotational Instability Turbulence
• The Ophiuchus DIsc Survey Employing ALMA (ODISEA)-III: the evolution of substructures in massive discs at 3-5 au resolution
• Frankenstein: Protoplanetary disc brightness profile reconstruction at sub-beam resolution with a rapid Gaussian process
• Dust-trapping vortices and a potentially planet-triggered spiral wake in the pre-transitional disk of V1247 Orionis
• High gas/dust size ratio indicating efficient radial drift in the mm-faint CX Tau disk
• Flybys in protoplanetary discs: II. Observational signatures
• Gas Disk Sizes from CO Line Observations: A Test of Angular Momentum Evolution
• Why do M dwarfs have more transiting planets?
• Size and structures of disks around very low mass stars in the Taurus star-forming region
• Rossby wave instability does not require sharp resistivity gradients
• Limits on Millimeter Continuum Emission from Circumplanetary Material in the DSHARP Disks
• Revealing signatures of planets migrating in protoplanetary discs with ALMA multi-wavelength observations
• The effect of stellar multiplicity on protoplanetary discs. A NIR survey of the Lupus star forming region
• Tracing pebble drift and trapping using radial carbon depletion profiles in protoplanetary disks
• Constraining the radial drift of millimeter-sized grains in the protoplanetary disks in Lupus
• The ALMA view of MP Mus (PDS 66): a protoplanetary disk with no visible gaps down to 4 au scales
• Turbulent Dust-trapping Rings as Efficient Sites for Planetesimal Formation
• Dust ring and gap formation by gas flow induced by low-mass planets embedded in protoplanetary disks $\mathrm{I}$. Steady-state model
• Magnetic field tuning of the valley population in the Weyl phase of Nd${}_2$Ir${}_2$O${}_7$

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