Scale Hierarchies in Gravitational-Wave Binaries: A New Path for Probing Fundamental Physics

Asymmetric binaries form a distinct class of coalescing systems and are expected to be important sources for future gravitational-wave observations. In these systems, a compact object orbits a significantly more massive companion, generating gravitational waves across a broad frequency range—from the milliHertz to the Hertz band—depending on the masses and spins of the components. Their slow orbital evolution allows for detailed modeling of the underlying spacetime, providing a natural setting for precision tests of gravity and searches for additional fundamental fields.