Velocity vector fields in the (α, e₂) plane depicting the routes of tidal evolution in the vicinity of each Kepler CBP. The arrows show the direction of orbital evolution throughout the plane, although its size was kept constant and is thus not representative of the magnitude of the derivatives. The green curves corresponds to ) while the magenta curves indicate the location of the capture eccentricity e_cap as defined by Eq. (26). The pale pink region correspond to values of the orbital elements identified as unstable according to the criterion by Holman & Wiegert (1999). Current positions of the Kepler CBPs are shown in blue circles.