Intrinsic properties of high luminosity blue stars from observations of multiple systems.

Spectrophotometric BCD and photometric UBV data are reported and analyzed for O stars and blue giants that are the brightest members of some multiple system. Spectrophotometric parameters obtained were: the visible gradient phi-rb, the blue gradient phi-b, the ultraviolet gradient phi-uv, the Balmer discontinuity D, and the position of the Balmer discontinuity. Intrinsic colors obtained are bluer than Johnson's scale, but redder than those of corresponding main sequence stars. The spectrophotometric colors of the O stars were fairly dispersed, which is not wholly attributed to the small number of measurements. Significant disagreement was obtained between the colors obtained for the O stars and the generally accepted ones or those given theoretically by the classical ETL or NETL models.