  The Kozai mechanism for a hierarchical triple system could reduce the merger
time of inner eccentric binary emitting gravitational waves (GWs), and has been
qualitatively explained with the secular theory that is derived by averaging
short-term orbital revolutions. However, with the secular theory, the minimum
value of the inner pericenter distance could be excessively limited by the
averaging operation. Compared with traditional predictions, the actual
evolution of an eccentric inner binary could be accompanied by (i) a higher
characteristic frequency of the pulse-like GWs around its pericenter passages,
and (ii) a larger residual eccentricity at its final inspiral phase. These
findings would be important for GW astronomy with the forthcoming advanced
detectors.
