1994A&A...285..609M

We present measurements of the emission core width W₀ and the wavelength separation of the K₁ dips, W₁, of the Ca II H and K emission lines observed on high-dispersion spectra of 28 chromospherically active binary systems (RS CVn and BY Dra stars) and 18 single active stars. We test the width-luminosity correlations (the Wilson-Bappu (WB) effect, and (W₁, M_V)) in these very active stars and analyse the influence of the activity level (I_K3) and the rotational broadening (Vsin i) in these correlations. We have found that for very active stars the emission widths, both W₀ and W₁, are larger than expected from previously accepted width-luminosity relations. The stars with strong emission intensities, I_K3, and large values of Vsin i seem to present larger values of W₀ than resulted from WB relation, the effect of the rotational velocity being the most remarkable. On the contrary, W₁ is strongly influenced by I_K3 but the effect of the rotational broadening is lesser. We also analyse the behaviour of the Ca II H and K line parameters in these very active stars in relation with less active stars and we found that the increase of W₁ and I_K1 with I_K3 presents a flattening for the most active stars which is different for each value of W₀. Finally we also find a Hε width-luminosity correlation in the stars of the sample in which this emission line is present.