Effects of dynamical tides on gravitational wave signals from eccentric double white dwarf systems

The tidal response of compact stars in a binary system is a useful probe of the stellar interior. While the equilibrium part of the tide dominates the matter response for systems with a large orbital separation, the dynamical tide starts to become important for small separation as the orbital period gets closer to the matter response time. In this talk, I will discuss the effect of dynamical tides on the gravitational wave signals from eccentric binary white dwarf systems. These systems are one of the target sources of the proposed space-based gravitational wave detector (LISA). We show numerically that for orbits with high eccentricities and small separations, the dynamical tide can cause a chaotic growth of the normal mode amplitudes and cause the orbit to evolve in a random manner, leading to a chaotic waveform. Meanwhile, for systems with lower eccentricities and larger separations, the dynamical tide causes a perturbative change in the orbital motion, increasing the rate of periastron precession compared to an orbit with only equilibrium tide. Including such an effect is crucial in determining the tidal properties of white dwarfs.