Determine accretion rates and radiative efficiencies of non-short-period low-mass X-ray binaries

Determine the accretion rates of low-mass X-ray binaries outside the short-period ultra-compact regime, and thereby determine their radiative efficiencies, despite the mixed and uncertain orbital-angular-momentum-transfer processes in these systems.

Background

The paper states that accretion rates can be reliably calculated only for short-period UCXBs with orbital periods below 40 minutes, for which gravitational radiation dominates angular-momentum loss. For UCXBs with periods between 40 and 80 minutes and for other low-mass X-ray binaries with periods above 80 minutes, multiple mechanisms—including gravitational radiation, magnetic braking, and mass loss—may govern angular-momentum transfer. Because the accretion rates in these systems are unknown, their radiative efficiencies cannot currently be calculated, preventing a direct comparison with the short-period systems analyzed in the paper.