Synthetic Line Profiles for Pulsating Red Giants

Pulsation influences atmospheric structures of variable AGB stars (Miras) considerably. Spectral lines of the CO dv=3 vibration-rotation bands (at 1.6mue) therefore have a very characteristic appearance in time series of high-resolution spectra. Coupled to the light cycle they can be observed blue- or red-shifted, for some phases even line doubling is found. This is being explained by radial pulsations and shock fronts emerging in the atmospheres. Based on dynamic model atmospheres synthetic CO line profiles were calculated consistently, reproducing this scenario qualitatively.