Modelling NIR molecular lines for Miras

Abstract

The atmospheric structure of Mira variables is considerably influenced by pulsation. Molecular absorption lines in the near-infrared (NIR), especially second overtone CO lines, show therefore a characteristic behaviour in time-series of high-resolution spectra. We computed synthetic CO line profiles based on a new dynamic model atmosphere and derived radial velocities (RVs) from the Doppler shifted lines. For the first time, we could quantitatively reproduce observations of the very typical, discontinuous RV curves.

2 pages, 1 figure, to be published in: Proc. "Stellar pulsation and evolution", Mem.Soc.Astron.Ital., Vol.76 (2005)