Close binary systems in star-forming regions: EQ Ori in the Ori I association

Photoelectric (UBVR) observations of the eclipsing variable EQ Ori are pres ented. The ephemerides of primary minima are refined, and the range of the star's light variations is determined. All light curves are solved by Lavro v's direct method, and highly accurate photometric orbital elements art: ob tained for the system. The magnitudes and colors of each component are calc ulated and analyzed in two-color (U-B)-(B-V) and (U-B)-(V-R) diagrams. The system's primary component is classified as a metallic-line Am star. The ab solute parameters of the components are estimated, and the binary is classi fied as a detached system with a subgiant: AO V and K2 IV. EQ Ori has a fai nt physical companion, which causes the epochs of primary minimum to be sys tematically displaced with a period of about 30 years. The expected paramet ers of the distant companion art: estimated. The system's components are at a pre-ZAMS evolutionary stage, with their age being 2 x 10(6) years. EQ Or i is thought to be a member of the Ori I association. (C) 2001 MAIK "Nauka/ Interperiodica".