1994A&A...288..529M

This paper presents the results of the first application of Doppler Imaging to solar-type contact binaries. Our aim was to examine whether this technique can help discriminate between various types of surface inhomogeneities (dark vs. bright star-spots) which are produced by different physical processes and which affect not only the surface brightness distribution but also the system's secular evolution. Simultaneous high dispersion spectroscopy and photometry for the systems AE Phe and YY Eri were obtained at ESO using the Coude Auxiliary Telescope (CAT) and the 50 cm telescope. The observed light-curves were solved by means of the latest version of the Wilson-Devinney program. Doppler maps were constructed taking into account the effects of fast rotation and proximity of the system's components. Doppler maps reveal the presence of dark spots on both systems. For AE Phe, this result is in agreement with the light-curve solution. Indirect evidence of enhanced chromospheric emission is also found. This emission appears to be more intense on the primary components.