Structure of a protobinary system: an asymmetric circumbinary disk and spiral arms

Abstract

We investigate the gas structures around young binary stars by using three-dimensional numerical simulations. Each model exhibits circumstellar disks, spiral arms, and a circumbinary disk with an inner gap or cavity. The circumbinary disk has an asymmetric pattern rotating at an angular velocity of approximately one-fourth of the binary orbit of the moderate-temperature models. Because of this asymmetry, the circumbinary disk has a density bump and a vortex, both of which continue to exist until the end of our calculation. The density bump and vortex are attributed to enhanced angular momentum, which is promoted by the gravitational torque of the stars. In a hot model ($c\ge 2.0$), the asymmetry rotates considerably more slowly than in the moderate-temperature models. The cold models ($c\le 0.02$) exhibit eccentric circumbinary disks, the precession of which is approximated by a secular motion of the ballistic particles. The asymmetry in the circumbinary disk does not depend on the mass ratio, but it becomes less clear as the specific angular momentum of the infalling envelope increases. The relative accretion rate onto the stars is sensitive to the angular momentum of the infalling envelope. For envelopes with constant angular momentum, the secondary tends to have a higher accretion rate than the primary, except in very low angular momentum cases. For envelopes with a constant angular velocity, the primary has a higher accretion rate than the secondary because gas with low specific angular momentum falls along the polar directions.

12 pages, 22 figures, Accepted by ApJ

References in corpus (20)

• A Triple Protostar System Formed via Fragmentation of a Gravitationally Unstable Disk
• Viscous Hydrodynamics Simulations of Circumbinary Accretion Discs: Variability, Quasi-Steady State, and Angular Momentum Transfer
• Signs of Early-Stage Disk Growth Revealed with ALMA
• On the Stability of Elliptical Vortices in Accretion Discs
• On the origin of horseshoes in transitional discs
• Three Dimensional MHD Simulation of Circumbinary Accretion Disks -2. Net Accretion Rate
• Precession and accretion in circumbinary discs: The case of HD 104237
• Spiral Arms, Infall, and Misalignment of the Circumbinary Disk from the Circumstellar Disks in the Protostellar Binary System L1551 NE
• Angular Momentum Exchange by Gravitational Torques and Infall in the Circumbinary Disk of the Protostellar System L1551 NE
• A Spitzer Five-Band Analysis of the Jupiter-Sized Planet TrES-1
• Active-Region Tilt Angles: Magnetic Versus White-Light Determinations of Joy's Law
• ALMA observations of a high-density core in Taurus: dynamical gas interaction at the possible site of a multiple star formation
• Star formation in turbulent molecular clouds with colliding flow
• An origin of arc structures deeply embedded in dense molecular cloud cores
• The evolution of the mass ratio of accreting binaries: the role of gas temperature
• Circumbinary Ring, Circumstellar disks and accretion in the binary system UY Aurigae
• Near-Infrared Coronagraphic Observations of the T Tauri Binary System UY Aur
• Rotationally-Driven Fragmentation for the Formation of the Binary Protostellar System L1551 IRS 5
• Evolution of binary seeds in collapsing protostellar gas clouds
• Formation of the Unequal-Mass Binary Protostars in L1551 NE by Rotationally-Driven Fragmentation

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