Lecturer:
Olga Barsunova, Pulkovo Observatory, St.Petersburg, Russia

Title:
The low-mass companions of the young stars: the observational signs in the photometry of V718 Per and BF Ori.

Abstract:
It is very difficult to search the low-mass companions in the young stars neighborhood because of their own
spectral periodicity. It makes impossible to use spectral observations for searching the radial velocities
periodic oscillations. In these cases as it is shown in our articles, one can use the photometric monitoring.
In this talk I present the results of the observational monitoring of two young objects V718 Per and BF Ori.
Both represent a complicated photometric behavior. In V718 Per case we observe eclipses with periods 4.7 and
0.6 years. In photometrical behavior of BF Ori the slow cyclic component was observed against a background of
the fast accidental brightness variability with amplitudes by some magnitudes. The durations of the cycles are
11-12 years. It was shown that such photometric behavior of these stars may be a result of the periodic
perturbations in the circumstellar disks due to the low-mass companions motion.