Ω₁–q parameter cross-section for J150822. Points below the lower dotted line were not sampled since they correspond to physically implausible filling factors (F > 1); very high potentials, corresponding to highly unlikely detached configurations, were not sampled either. The upper dotted line indicates the location of the binary’s Roche lobe; the primary component is (with high probability) just below this line, and hence probably just overfills the Roche lobe.