DISENTANGLING OF COMPOSITE SPECTRA

A novel technique for the reconstruction of the individual spectra of the components of well detached binaries is presented. The method requ ires a set of composite spectra at different phases. It is based on a singular value decomposition (SVD), the appropriate method of treating a linear problem which is both overdetermined and rank deficient. The algorithm also yields precise radial velocities, even at phases where the lines are severely overlapping, e.g. near conjunction. This is a great advantage for the construction of radial velocity curves, especi ally the determination of system velocities and orbit eccentricities. The quality of the reconstructed spectra is demonstrated using CCD spe ctra of the BO.5 type binary V453 Cygni. The spectrum of the primary t aken during total eclipse in the secondary minimum matches perfectly w ith the spectrum reconstructed from a set of seven composite spectra a t different phases out of eclipse. We conclude, that spectra which are reconstructed by means of the disentangling algorithm are well suited for quantitative spectroscopic work.