Poster abstract details

The results of radial velocity monitoring and high-resolution spectroscopy are presented for selected post-AGB stars. High-resolution optical spectra are analyzed in details for three cool R CrB candidate stars to clarify the evolutionary status of these rare objects. Long-term observations are performed for three proto-planetary nebulae (PPN) with the main goal to understand better the pulsation properties and dynamical phenomena in the extended atmospheres. The time series of high-resolution optical spectra are discussed for IRAS22272+5435. The spectrum of IRAS22272+5435 originates in the circumstellar envelope (CSE) and throughout different layers in the atmosphere of HD235858. A large number of narrow molecular lines originated in the CSE are present in the optical spectrum of IRAS22272+5435, blueshifted relative to the photospheric lines. Time series of high resolution spectra shows splitting of low-excitation atomic absorption lines and significant changes in the intensity of C_2 and CN features originated in the extended atmosphere significantly affected by pulsations.