A Comparison of the Near Ultraviolet Continuum and Chromospheric Emission Line Fluxes of the Late Type Giant Stars

Abstract

We investigate the near-ultraviolet high-resolution LWR spectra of the stars α Cas, β And, α Tau, β Gem, γ Cru, α Boo, and β Peg, obtained with the aid of the International Ultraviolet Explorer Satellite. We have given here a list of the strongest and most prevalent emission lines in the near-ultraviolet spectra of α Boo, KlIIIp, and β Peg, M2.5II-III which have the same luminosity class and different spectral type. The near-ultraviolet continuum flux measurements and integrated emission line fluxes of these stars for the 2500–3200 Å region are presented in order to compare the variations in the appearance of the near-ultraviolet flux distribution with the temperature structure of their chromospheres for K and M giant stars. We also discuss differences between observed and calculated fluxes found from the Planck function.