(24\fd80091 \pm \rm 0\fd00044)\, E\end{aligned}$$

where $N$ is the cycle number. This period was used to phase the light curve shown in Fig.3. From this figure we infer the following: (1) at some epochs the secondary eclipse becomes deeper than the primary eclipse, (2) the secondary eclipse has larger variability (scatter) than the primary eclipse, (3) the regularity of time strings reflected in colored data suggests that the non-orbital variability occurs mostly in time scales of hundred of days, (4) while the secondary eclipse changes its depth as well as its width, the primary one make it primarily in depth, and with less amplitude than the secondary eclipse, (5) the long cycle, revealed by the scattered data, becomes more evident outside the primary eclipse, suggesting that the light source becomes at least partially eclipsed during primary eclipse, (6) there is a tendency for the primary eclipse in being deeper with time, and (7) the orbital period seems to be very stable during the observing period.

We tested the last statement making an analysis of the times of primary eclipse with the “period-change equation” . This method assumes a constant rate of change of the period and compares predicted times with 