Testing the Limits of Waveform Modelling Approximations for Eccentric and Precessing Compact Binaries

Orbital eccentricity and spin precession are powerful tracers of the dynamical formation of compact binaries, making accurate waveform models that capture both effects essential for reliable astrophysical inference. The coprecessing frame is a cornerstone of precessing waveform models, and simplifies the problem by decoupling orbital precession from the underlying aligned-spin dynamics. In this talk, I will assess the limits of this approximation for systems exhibiting both eccentricity and precession, using SXS numerical relativity simulations. By testing how well these two effects can be separated within this framework, I will determine whether a coprecessing frame approach remains a robust foundation for next-generation models that aim to capture the full complexity of generic binary dynamics.