Close binary evolution I. The tidally induced shear mixing in rotating binaries

Abstract

We study how tides in a binary system induce some specific internal shear mixing, able to substantially modify the evolution of close binaries prior to mass transfer. We construct numerical models accounting for tidal interactions, meridional circulation, transport of angular momentum, shears and horizontal turbulence and consider a variety of orbital periods and initial rotation velocities. Depending on orbital periods and rotation velocities, tidal effects may spin down (spin down Case) or spin up (spin up Case) the axial rotation. In both cases, tides may induce a large internal differential rotation. The resulting tidally induced shear mixing (TISM) is so efficient that the internal distributions of angular velocity and chemical elements are greatly influenced. The evolutionary tracks are modified, and in both cases of spin down and spin up, large amounts of nitrogen can be transported to the stellar surfaces before any binary mass transfer. Meridional circulation, when properly treated as an advection, always tends to counteract the tidal interaction, tending to spin up the surface when it is braked down and vice versa. As a consequence, the times needed for the axial angular velocity to become equal to the orbital angular velocity may be larger than given by typical synchronization timescales. Also, due to meridional circulation some differential rotation remains in tidally locked binary systems.

10 pages, 18 figures, Accepted for publication in Astronomy and Astrophysics

References in corpus (8)

• Grids of stellar models with rotation - I. Models from 0.8 to 120 Msun at solar metallicity (Z = 0.014)
• The rotation rates of massive stars: the role of binary interaction through tides, mass transfer and mergers
• The VLT-FLAMES Tarantula Survey VIII. Multiplicity properties of the O-type star population
• Rotational mixing in massive binaries: detached short-period systems
• The VLT-FLAMES survey of massive stars: constraints on stellar evolution from the chemical compositions of rapidly rotating Galactic and Magellanic Cloud B-type stars
• Neon Abundances in B-Stars of the Orion Association: Solving the Solar Model Problem?
• Tides in asynchronous binary systems
• Mixing of CNO-cycled matter in massive stars

Cited by in corpus (33)

• Merging binary black holes formed through chemically homogeneous evolution in short-period stellar binaries
• The spin of the second-born black hole in coalescing binary black holes
• The redshift evolution of the binary black hole merger rate: a weighty matter
• The MiMeS Survey of Magnetism in Massive Stars: CNO surface abundances of Galactic O stars
• Massive star evolution in close binaries:conditions for homogeneous chemical evolution
• Investigating the lack of main-sequence companions to massive Be stars
• Fundamental properties of nearby single early B-type stars
• Discovery of the massive overcontact binary VFTS 352: Evidence for enhanced internal mixing
• HD 156324: a tidally locked magnetic triple spectroscopic binary with a disrupted magnetosphere
• The Shortest-period Wolf-Rayet binary in the Small Magellanic Cloud: Part of a high-order multiple system
• Isochrone-cloud fitting of the extended Main-Sequence Turn-Off of young clusters
• Chemical abundances of fast-rotating massive stars. I. Description of the methods and individual results
• Coherent radio emission from a population of RS Canum Venaticorum systems
• Close binary evolution. III. Impact of tides, wind magnetic braking, and internal angular momentum transport
• A Strict Test of Stellar Evolution Models: The Absolute Dimensions of Massive Benchmark Eclipsing Binary V578 Mon
• The effects of surface fossil magnetic fields on massive star evolution: III. The case of $\tau$ Sco
• Chemical abundances of fast-rotating massive stars. II. Interpretation and comparison with evolutionary models
• Apsidal motion in the massive binary HD 152248 -- Constraining the internal structure of the stars
• Spinning up the Surface: Evidence for Planetary Engulfment or Unexpected Angular Momentum Transport?
• Induced differential rotation and mixing in asynchronous binary stars
• Apsidal motion in the massive binary HD152248
• Binary evolution using the theory of osculating orbits: conservative Algol evolution
• Tides and angular momentum redistribution inside low-mass stars hosting planets: a first dynamical model
• Extreme mass ratios and fast rotation in three massive binaries
• Prompt stellar and binary black hole mergers in tight triples: Insights from chemically homogeneous evolution
• Supernovae from rotating stars
• Close binary evolution based on Gaia DR2: the origin of late WC-type Wolf-Rayet stars with low luminosity
• A comprehensive grid of massive binary evolution models for the Galaxy - Surface properties of post-mass transfer stars
• Impact of rotation on stellar models
• Massive stars, successes and challenges
• The Environments around W Serpentis Systems: Independent Limits on System Masses and Extended Envelopes
• Chemical evolution of close massive binaries -- tidally-enhanced or tidally-suppressed mixing?
• Detailed evolutionary models of massive contact binaries: I. Model grids and synthetic populations for the Magellanic Clouds