Photospheric and chromospheric active regions in four young solar-type stars

We present a photometric and spectroscopic study of four G-K dwarfs, namely HD 166, epsilon Eri, chi(1) Ori, and kappa(1) Cet. In three cases, we find a clear spatial association between photospheric and chromospheric active regions. For chi(1) Ori we do not find appreciable variations of photospheric temperature or chromospheric H alpha emission. We applied a spot / plage model to the observed rotational modulation of temperature and flux to derive spot / plage parameters and to reconstruct a rough three-dimensional'' map of the outer atmosphere of kappa(1) Cet, HD 166, and epsilon Eri.