Orbital eccentricity of the parameterized time scale of the tidally driven orbital circularization, ε_r. The top panel shows the position of all binary candidates in the parameter plane. The histogram in the bottom panel depicts the distribution of ε_r for the systems with an oscillating primary, for which the evolutionary state could be determind from seismology. The color distinguishes between the evolutionary states of secondary clump (2RC), red clump (RC), red giant branch (RGB) in purple, teal, and orange, respectively. Because of their small number and nearby evolutionary state, main sequence and subgiant primaries are shown as one group in yellow (MS+SG). The grey dashed line marked the proposed value of ε_crit.