Unveiling the Formation Channel of Eccentric Neutron Star–Black Hole Mergers

The formation history of compact binary systems remains one of the key open questions in astrophysics. Theoretical studies generally favor the isolated binary evolution channel for neutron star–black hole (NSBH) systems, which tends to produce nearly circular orbits. However, recent analyses of the gravitational-wave event GW200105, which exhibits measurable eccentricity, suggest the existence of alternative formation channels. Eccentric NSBH mergers are also of particular interest because incorporating orbital eccentricity in gravitational-wave modeling allows for more precise inference of component masses and spins. In this work, we explore how such improved parameter estimation influences population-level studies of NSBH systems. Specifically, we demonstrate that accounting for eccentric systems can tighten constraints on astrophysical population parameters and help discriminate between competing formation scenarios.