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 ( \Delta t _ { I,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 - e ^ { 2 } ) ^ { 3 / 2 } \sim 15 { d } , close to the tidal circularization period P _ { circ } .
They may be presently migrating due to tidal dissipation and form a steady-state stream ( \sim 1 \% of stars ) feeding the close-binary population ( few- \% of stars ) .
If so , future Kepler data releases will reveal a growing number ( dozens ) of systems at longer periods , following { d } N / { d } \lg P \propto P ^ { 1 / 3 } with increasing eccentricities reaching e \rightarrow 0.98 for P \rightarrow 1000 { d } .
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 .