  Mergers of compact stellar remnant are prime targets for the LIGO/Virgo
gravitational wave detectors. One hopes that the gravitational wave signals
from these merger events can be used to study the mass and spin distribution of
stellar remnants, and provide information about black hole horizons and the
material properties of neutron stars. However, it has been suggested that
degeneracies in the way that the star's mass and spin are imprinted in the
waveforms may make it impossible to distinguish between black holes and neutron
stars. Here we show that the precession of the orbital plane due to spin-orbit
coupling breaks the mass-spin degeneracy, and allows us to distinguish between
standard neutron stars and alternative possibilities, such as black holes or
exotic neutron stars with large masses and spins.
