Study of the chromospheric eclipse of Zeta Aurigae, Autumn 2019

We analyze the degree of chromospheric variability of the K5 II star of the binary system ζ Aurigae (+B7V), through the analysis of the growth curve of the chromospheric absorption lines during the eclipse to determine the column density of the outer chromosphere of the giant. We find that the column densities and their gradient are markedly different from the values obtained in 1950 and 1989