SIMBAD references

We present the results of spectroscopic measurements of line spectra of the symbiotic star CH Cygni in the optical region of the EM spectrum. The observations extend over a period of two years (1987-89) and cover the quiescent state of the star. Although in most spectra the flat transition part of the curve of growth was predominant, a refined fitting procedure made possible the evaluation of the excitation temperature and microturbulent velocity for neutral metals in the red giant's photosphere. A regular decrease of the excitation temperature within the same interval for the investigated elements has been found, with the exception of Fe I for which the temperatures are higher. The microturbulent velocities show small erratic variations around a mean value, which is greater for Fe I than for the other elements. This could be explained by a stratification in the photosphere of the cool component.