Three-dimensional Doppler tomograms and detection of motions beyond the orbital plane in close binary systems

Abstract

The newly developed radioastronomical approach (RA) has been modified for the reconstruction of three-dimensional (3D) Doppler tomograms. The RA permits an unequal space distribution of the views of an object and a reduction in the number of required orbital phases when compared with the filtered back-projection technique. The 3D Doppler tomogram of the close binary system U Coronae Borealis was reconstructed on the basis of 47 spectra of the Hα line. The three strongest Hα emission features found on the map were the accretion annulus, the gas stream moving along the ballistic trajectory, and a high-intensity region moving at high velocity in a direction across the orbital plane. It was not possible to discover this latter feature using standard two-dimensional Doppler tomography. The new RA technique is a useful tool for the subsequent study of gas flows in close binary systems.