Tidal evolution of eccentric orbits in massive binary systems. II. Coupled resonance locking for two rotating main sequence stars

We extend our study of the tidal evolution of elliptic binary systems to the case of a system consisting of two 10 M_sun uniformly rotating main sequence stars. Previous work showed that in a system consisting of a 1.4 M_sun compact object in orbit about a 10 M_sun main sequence star stellar oscillation modes were prone to be excited nearly resonantly for prolonged periods of time. This resonance locking was shown to constitute an effective mechanism for orbital decay in moderately eccentric orbits. In this work we investigate in what ways the locking mechanism is altered if also the companion is tidally perturbed, also inducing orbital changes and potentially also being locked in resonance. We show that simultaneous locking can intensify the tidal excitations, and that resonance locking is a common phenomenon during the tidal evolution of eccentric double main sequence binary systems which speeds up the secular evolution significantly.