Chromospheric activity of red giants

We present result of our spectroscopic survey of red giant stars carried out between 1999 and 2004. In the spectra of least eight G and K giants: HD 7672, HD 50778, HD 62644, HD 78647, HD 81797, HD 110014, HD 107446 and HD 151249 we observed radial velocity variations which show clear evidences for chromospheric activity. The origins of the chromospheric activity of these stars axe star-spots, stellar wind in close binary systems, and nonradial pulsations. The spectroscopic detection of chromospheric activity is associated with the measurement of radial velocity variation, spectral line asymmetry and variation in the chromospheric activity indicators, like Ca II K emission fines in 3934 A. We applied the cross-correlation method to measure the stellar radial velocity with a precision of some 25 m/s and the asymmetry of the spectral line profile using the bisector velocity span.