Exploring a “Flow” of Highly Eccentric Binaries With Kepler

With 16-month Kepler data, 14 long-period (40 d - 265 d) eclipsing binaries on highly eccentric orbits (minimum e between 0. 5 and 0. 85) are recognized from their closely separated primary and secondary eclipses (tI, II = 3 d - 10 d). These systems confirm the existence of a previously hinted binary population situated near a constant angular momentum track at P (1-e²) ^ (3/2) ~ 15 d, close to the tidal circularization period Pcirc. They may be presently migrating due to tidal dissipation and form a steady-state stream (~1% of stars) feeding the close-binary population (few percent of stars). If so, future Kepler data releases will reveal a growing number (dozens) of systems at longer periods, following dN/dlgP P^ (1/3) with increasing eccentricities reaching e -> 0. 98 for P -> 1000d. Radial-velocity follow up of long-period eclipsing binaries with no secondary eclipses could offer a significantly larger sample. Orders of magnitude more (hundreds) may reveal their presence from periodic "eccentricity pulses", such as tidal ellipsoidal variations, near pericenter passages. Several new few-day-long eccentricity-pulse candidates with long period (P = 25 d - 80 d) are reported.