DYNAMICAL PHENOMENA IN THE ATMOSPHERE OF THE PROTO-PLANETARY NEBULA IRAS 22272+5435

Radial velocity monitoring of the star HD 235858 confirmed regular variations with a peak-to-peak amplitude of about 10 km s–1 and a period of about 131.2 days. The light, color, and velocity variations are typical for RV Tauri stars. Splitting of low-excitation atomic lines was detected. The components are both blue- and redshifted relative to the systemic velocity. Significant variations are observed in the intensity of C2 and CN lines. Variable emission in the Hα profile, splitting of low-excitation atomic absorption lines, appearance of CN emission lines, blue wings of strong lines, and recent reddening give evidence of shocks and mass outflow obviously induced by atmospheric pulsations.