Differential Rotation in Convective Envelopes: Constraints from Eclipsing Binaries

Abstract

Over time, tides synchronize the rotation periods of stars in a binary system to the orbital period. However, if the star exhibits differential rotation then only a portion of it can rotate at the orbital period, so the rotation period at the surface may not match the orbital period. The difference between the rotation and orbital periods can therefore be used to infer the extent of the differential rotation. We use a simple parameterization of differential rotation in stars with convective envelopes in circular orbits to predict the difference between the surface rotation period and the orbital period. Comparing this parameterization to observed eclipsing binary systems, we find that in the surface convection zones of stars in short-period binaries there is very little radial differential rotation, with $|r{\partial }_r\ln \Omega |<0.02$. This holds even for longer orbital periods, though it is harder to say which systems are synchronized at long periods, and larger differential rotation is degenerate with asynchronous rotation.

19 pages, published in MNRAS. Corrected typos and cases where solar/anti-solar were swapped

References in corpus (17)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Updated Electron-Conduction Opacities: The Impact on Low-Mass Stellar Models
• Tidal dissipation in stars and giant planets
• Slowing the Spins of Stellar Cores
• White Dwarf Rotation as a Function of Mass and a Dichotomy of Mode Linewidths: Kepler Observations of 27 Pulsating DA White Dwarfs Through K2 Campaign 8
• Coulomb tunneling for fusion reactions in dense matter: Path integral Monte Carlo versus mean field
• Low-frequency gravity waves in blue supergiants revealed by high-precision space photometry
• On differential rotation and overshooting in solar-like stars
• Tidal Synchronization and Differential Rotation of Kepler Eclipsing Binaries
• Surface rotation of Kepler red giant stars
• The dependence of convective core overshooting on stellar mass: semi-empirical determination using the diffusive approach with two different element mixtures
• Solar rotation rate and its gradients during cycle 23
• Period spacings of $\gamma$ Doradus pulsators in the \textit{Kepler} field: Rossby and gravity modes in 82 stars
• Rotation rate of the solar core as a key constraint to magnetic angular momentum transport in stellar interiors
• A Diagnostic for Localizing Red Giant Differential Rotation
• Kepler Eclipsing Binary Stars. V. Identification of 31 Eclipsing Binaries in the K2 Engineering Data-set
• Simple Scaling Relationships for Stellar Dynamos