Fragmentation of Dense Rotation-Dominated Structures Fed by Collapsing Gravomagneto-Sheetlets and Origin of Misaligned 100 au-Scale Binaries and Multiple Systems

Abstract

The majority of stars are in binary/multiple systems. How such systems form in turbulent, magnetized cores of molecular clouds in the presence of non-ideal MHD effects remains relatively under-explored. Through ATHENA++-based non-ideal MHD AMR simulations with ambipolar diffusion, we show that the collapsing protostellar envelope is dominated by dense gravo-magneto-sheetlets, a turbulence-warped version of the classic pseudodisk produced by anisotropic magnetic resistance to the gravitational collapse, in agreement with previous simulations of turbulent, magnetized single-star formation. The sheetlets feed mass, magnetic fields, and angular momentum to a Dense ROtation-Dominated (DROD) structure, which fragments into binary/multiple systems. This DROD fragmentation scenario is a more dynamic variant of the traditional disk fragmentation scenario for binary/multiple formation, with dense spiral filaments created by inhomogeneous feeding from the highly structured larger-scale sheetlets rather than the need for angular momentum transport, which is dominated by magnetic braking. Provided that the local material is sufficiently demagnetized, with a plasma-$\beta$ of 10 or more, collisions between the dense spiraling filaments play a key role in facilitating gravitational collapse and stellar companion formation by pushing the local magnetic Toomre parameter $Q_{\mathrm{m}}$ below unity. This mechanism can naturally produce {\it in situ} misaligned systems on the 100-au scale, often detected with high-resolution Atacama Large Millimeter Array (ALMA) observations. Our simulations also highlight the importance of non-ideal MHD effects, which affect whether fragmentation occurs and, if so, the masses and orbital parameters of the stellar companions formed.

References in corpus (30)

• Cold Dark Clouds: The Initial Conditions for Star Formation
• The Athena++ Adaptive Mesh Refinement Framework: Design and Magnetohydrodynamic Solvers
• On the Role of Disks in the Formation of Stellar Systems: A Numerical Parameter Study of Rapid Accretion
• Magnetic processes in a collapsing dense core. I Accretion and Ejection
• The VLA Nascent Disk and Multiplicity Survey of Perseus Protostars (VANDAM). II. Multiplicity of Protostars in the Perseus Molecular Cloud
• The Formation of Low-Mass Binary Star Systems Via Turbulent Fragmentation
• A Triple Protostar System Formed via Fragmentation of a Gravitationally Unstable Disk
• The effect of magnetic fields on star cluster formation
• Amplification, Saturation, and Q Thresholds for Runaway: Growth of Self-Gravitating Structures in Models of Magnetized Galactic Gas Disks
• Formation Scenario for Wide and Close Binary Systems
• Magnetically self-regulated formation of early protoplanetary discs
• Zoom-Simulations of Protoplanetary Disks starting from GMC scales
• Misaligned Protoplanetary Disks in a Young Binary System
• The Turbulent Origin of Outflow and Spin Misalignment in Multiple Star Systems
• What determines the formation and characteristics of protoplanetary discs?
• The Bridge: a transient phenomenon of forming stellar multiples
• The VLA Nascent Disk And Multiplicity (VANDAM) Survey of Perseus Protostars. Resolving the Sub-Arcsecond Binary System in NGC 1333 IRAS2A
• Protoplanetary disk birth in massive star forming clumps: the essential role of the magnetic field
• Collapse of turbulent massive cores with ambipolar diffusion and hybrid radiative transfer I. Accretion and multiplicity
• Disk Formation in Magnetized Dense Cores with Turbulence and Ambipolar Diffusion
• Disc formation and fragmentation using radiative non-ideal magnetohydrodynamics
• Formation and evolution of protostellar accretion discs. I. Angular-momentum budget, gravitational self-regulation, and numerical convergence
• Orbital and Mass Ratio Evolution of Protobinaries Driven by Magnetic Braking
• FAUST III. Misaligned rotations of the envelope, outflow, and disks in the multiple protostellar system of VLA 1623$-$2417
• The Athena++ Adaptive Mesh Refinement Framework: Multigrid Solvers for Self-Gravity
• Kinematic Analysis of a Protostellar Multiple System: Measuring the Protostar Masses and Assessing Gravitational Instability in the Disks of L1448 IRS3B and L1448 IRS3A
• Determining the physical conditions of extremely young Class 0 circumbinary disk around VLA1623A
• Collapse and Fragmentation of Magnetic Molecular Cloud Cores with the Enzo AMR MHD Code. I. Uniform Density Sphere
• The role of magnetic fields in the formation of multiple massive stars
• Impact of Magnetic Braking on High-mass Close Binary Formation

Cited by in corpus (1)

• An Eccentric Massive Protobinary Assembled via a Core-merger Parabolic Encounter