During their visual light minima ES Aql and Z UMi manifested brightness and color behavior typical of this type of variability: a decrease or increase in the color indices as the brightness decreases and an increase as the normal state is recovered. The molecular spectrum of Z UMi during the ...
Fine structure of the red giant clump from HIPPARCOS data, and distance determinations based on its mean magnitude and therefore an ideal standard candle, which could be calibrated with local clump stars whose absolute brightness is known from Hipparcos parallaxes. This... G Léo,MAT Groenewegen,...