Atmospheric dynamics in carbon-rich Miras. I. Model atmospheres and synthetic line profiles

Author(s)
Walter Nowotny-Schipper, Bernhard Aringer
Abstract

Atmospheres of evolved AGB stars are heavily affected by pulsation, dust formation and mass loss, and they can become very extended. Time series of observed high-resolution spectra proved to be a useful tool to study atmospheric dynamics throughout the outer layers of these pulsating red giants. Originating at various depths, different molecular spectral lines observed in the near-infrared can be used to probe gas velocities there for different phases during the lightcycle. Dynamic model atmospheres are needed to represent the complicated structures of Mira variables properly. An important aspect which should be reproduced by the models is the variation of line profiles due to the influence of gas velocities. Based on a dynamic model, synthetic spectra (containing CO and CN lines) were calculated, using an LTE radiative transfer code that includes velocity effects. It is shown that profiles of lines that sample different depths qualitatively reproduce the behaviour expected from observations.

Organisation(s)
Department of Astrophysics
Journal
Astronomy & Astrophysics
Volume
437
Pages
273-284
No. of pages
12
ISSN
0004-6361
Publication date
2005
Peer reviewed
Yes
Austrian Fields of Science 2012
1030 Physics, Astronomy
Portal url
https://ucrisportal.univie.ac.at/en/publications/416d76f8-75db-407a-bf1e-1ebb960ea36f