Induced differential rotation and mixing in asynchronous binary stars

Abstract

Rotation contributes to internal mixing processes and observed variability in massive stars. A significant number of binary stars are not in strict synchronous rotation, including all eccentric systems. This leads to a tidally induced and time-variable differential rotation structure. We present a method for exploring the rotation structure of asynchronously rotating binaries. We solve the equations of motion of a 3D grid of volume elements located above the rigidly rotating core in the presence of gravitational, centrifugal, Coriolis, gas pressure and viscous forces to obtain the angular velocity as a function of the three spatial coordinates and time. We find that the induced rotation structure and its temporal variability depend on the degree of departure from synchronicity. In eccentric systems, the structure changes over the orbital cycle with maximum amplitudes occurring potentially at orbital phases other than periastron passage. We discuss the possible role of the time-dependent tidal flows in enhancing the mixing efficiency and speculate that, in this context, slowly rotating asynchronous binaries could have more efficient mixing than the analogous more rapidly rotating but tidally locked systems. We find that some observed nitrogen abundances depend on the orbital inclination, which, if real, would imply an inhomogeneous chemical distribution over the stellar surface or that tidally induced spectral line variability, which is strongest near the equator, affects the abundance determinations. Our models predict that, neglecting other angular momentum transfer mechanisms, a pronounced initial differential rotation structure converges toward average uniform rotation on the viscous timescale. We suggest that by taking into account the processes that are triggered by asynchronous rotation, a broader perspective of binary star structure, evolution and variability may be gleaned.

arXiv comment21 pages, 18 figures

References in corpus (49)

• Grids of stellar models with rotation - I. Models from 0.8 to 120 Msun at solar metallicity (Z = 0.014)
• Presupernova Evolution of Rotating Massive Stars I: Numerical Method and Evolution of the Internal Stellar Structure
• Pre-Supernova Evolution of Massive Single and Binary Stars
• Rotating Massive Main-Sequence Stars I: Grids of Evolutionary Models and Isochrones
• Presupernova Evolution of Differentially Rotating Massive Stars Including Magnetic Fields
• The evolution of rotating stars
• Tidal dissipation in stars and giant planets
• Seismic constraints on the radial dependence of the internal rotation profiles of six Kepler subgiants and young red giants
• Sub-surface convection zones in hot massive stars and their observable consequences
• Angular Momentum Transport in Stellar Interiors
• Rotational mixing in massive binaries: detached short-period systems
• Probing the core structure and evolution of red giants using gravity-dominated mixed modes observed with Kepler
• KOI-54: The Kepler Discovery of Tidally-Excited Pulsations and Brightenings in a Highly Eccentric Binary
• Stellar Evolution with Rotation and Magnetic Fields IV: The Solar Rotation Profile
• On shear-induced turbulence in rotating stars
• The impact of companions on stellar evolution
• White dwarf spins from low mass stellar evolution models
• Tidal dissipation in binary systems
• Heartbeat Stars, Tidally Excited Oscillations, and Resonance Locking
• Tidal Excitation of Modes in Binary Systems with Applications to Binary Pulsars
• On Dissipation inside Turbulent Convection Zones from 3D Simulations of Solar Convection
• Direct Calculation of the Turbulent Dissipation Efficiency in Anelastic Convection
• The Tarantula Massive Binary Monitoring: III. Atmosphere analysis of double-lined spectroscopic systems
• Modeling of Magneto-Rotational Stellar Evolution I. Method and first applications
• Close binary evolution I. The tidally induced shear mixing in rotating binaries
• Anisotropic turbulent transport in stably stratified rotating stellar radiation zones
• Observational consequences of turbulent pressure in the envelopes of massive stars
• The Most Massive Heartbeat: An In-depth Analysis of ι Orionis
• Eccentric binaries: Tidal flows and periastron events
• Spot patterns and differential rotation in the eclipsing pre-CV binary,V471 Tau
• Shear mixing in stellar radiative zones I. Effect of thermal diffusion and chemical stratification
• Tides in asynchronous binary systems
• Interplay between pulsations and mass loss in the blue supergiant 55 Cygnus = HD 198478
• Tidally Excited Oscillations in Heartbeat Binary Stars: Pulsation Phases and Mode Identification
• Spectral modelling of massive binary systems
• Fossil field decay due to nonlinear tides in massive binaries
• Stellar modelling of Spica, a high-mass spectroscopic binary with a beta Cep variable primary component
• Turbulent transport in a strongly stratified forced shear layer with thermal diffusion
• Horizontal shear instabilities at low Prandtl number
• Horizontal shear instabilities in rotating stellar radiation zones: II. Effects of the full Coriolis acceleration
• Evolution of rotation in rapidly rotating early-type stars during the main sequence with 2D models
• Physical properties and CNO abundances for high-mass stars in four main-sequence detached eclipsing binaries: V478 Cyg, AH Cep, V453 Cyg and V578 Mon
• Internal circulation in tidally locked massive binary stars -- Consequences for double black hole formation
• Line-profile variability from tidal flows in Alpha Virginis (Spica)
• Tidal effects on the radial velocity curve of HD77581 (Vela X-1)
• Spectral modelling of the Alpha Virginis (Spica) binary system
• Tides and angular momentum redistribution inside low-mass stars hosting planets: a first dynamical model
• Alpha Virginis: line-profile variations and orbital elements
• Tidal Flows in asynchronous binaries: The beta-factor

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