Abstrakt
We present an improved model of triple star Delta Orionis A. For the first time we were able to disentangle the very weak spectral lines of the secondary in the blue parts of the optical spectrum and derive a reliable mass ratio q = 0:415.
Along with light-curve solutions, based on photometry from the SMEI, MOST and BRITE satellites, we obtained realistic masses and radii of both components of the close binary.