The Wilson-Bappu effect and other CA-II H-Line and K-line parameters relationships in chromospherically active binaries

© European Southern Observatory. © EDP Sciences. The INT 2.5m on the island of La Palma and the 2.2m telescope at Calar Alto Observatory are operated respectively, by the Royal Greenwich Observatory at the Spanish Observatorio del Roque de Los Muchachos (Instituto de Astrofísica de Canarias), and the Max Planck lnstitut für Astronomie at the Centro Astronómico Hispano-Alemán of Calar Alto (Almería, Spain). We want to express our gratitude to the staff of both Observatories for their help during the observations. This work has been supported by the Universidad Com­plutense de Madrid and the Spanish Dirección General de Investigación Científica y Técnica (DGICYT) under grant PB91-0348.
We present measurements of the emission core width W_0 and the wavelength separation of the K_1 dips, W_1, 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 (W_1, 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 W_0 and W_1, 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 W_0 than resulted from WB relation, the effect of the rotational velocity being the most remarkable. On the contrary, W_1 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 W_1 and I_K1 With I_K3 presents a flattening for the most active stars which is different for each value of W_0. Finally we also find a Hepsilon width-luminosity correlation in the stars of the sample in which this emission line is present.
Universidad Complutense de Madrid (UCM)
Dirección General de Investigación Científica y Técnica (DGICYT), España
Ministerio de Economía y Competitividad (MINECO), España
Depto. de Física de la Tierra y Astrofísica
Fac. de Ciencias Físicas
TRUE
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