Subo Dong, Boaz Katz, Aristotle Socrates
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) ~
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 (~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 \propto 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.
View original:
http://arxiv.org/abs/1201.4399
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