Uvby-beta electrophotometry of Trapezium type multiple systems with the primary star of O-B2 spectral type. I.

Results are presented from eletrophotometric observations of 41 components of 12 Trapezium-type multiple systems. The observations were made in the Stromgren and Crawford six-color photometric system using the 125-cm optical mirror telescope at the Abastumani (USSR) Astrophysical Observatory. The (b-y), M(1), C(1), and beta color indices for the sources are listed. The components are ascribed to the B, AF, and A spectral classes according to the Stromgren criteria. Also, the absolute magnitudes, effective temperatures, and gravitational forces on the stellar surfaces of the sources are determined.