Dynamical tide in solar-type binaries

Circularization of late-type main-sequence binaries is usually attributed to turbulent convection, while that of early-type binaries is explained by resonant excitation of gr-modes. We show that the latter mechanism also operates in solar-type stars and is at least as effective as convection despite inefficient damping of g-modes in the radiative core. The maximum period at which this mechanism can circularize a binary composed of solar-type stars in 10¹⁰ yr is as low as 3 days, if the modes are damped by radiative diffusion only and g-mode resonances are fixed, or as high as 6 days if one allows for evolution of the resonances and for nonlinear damping near inner turning points. Even the larger theoretical period falls short of the observed transition period by a factor of 2.