Recalibration of the Wilson-Bappu Effect Using the Singly Ionized Magnesium K Line

Abstract

A new calibration of the Wilson-Bappu effect is presented using data from a survey of the singly ionized magnesium (Mg ii) h and k lines (near 280 nm) taken from the archives of the International Ultraviolet Explorer satellite. Our sample consisted of 94 stars with absolute magnitudes derived from parallaxes reported from Hipparcos. We describe the dependencies of the base widths, peak widths, and full widths at half-maximum (FWHM) on the fundamental stellar parameters T_eff, metallicity, log g, and activity.