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Paper: Non-Radial Modes in Classical Cepheids — What to Look for in Spectroscopy?
Volume: 529, RR Lyrae/Cepheid 2019: Frontiers of Classical Pulsators
Page: 125
Authors: Netzel, H.; Kolenberg, K.
Abstract: In recent years, additional signals have been detected in the power spectra of photometric observations of RR Lyrae stars and classical Cepheids. These additional signals show up in stars pulsating in the radial first overtone mode, and due to the current hypothesis, they might correspond to non-radial modes of degrees 7, 8 and 9 for Cepheids or 8 and 9 for RR Lyrae stars. Non-radial modes of such high degrees usually should have small amplitudes in the photometric data. An alternative source of information on the nature of these additional signals lays in the study of line profile variations from spectroscopic data. However, the small amplitudes of the additional modes and their high degree might hamper their detection. In this study, we show results of the analysis of synthetic line profile variations for classical Cepheids in which, besides the main radial mode, there is an additional non-radial mode of degree 7, 8 or 9. The goal of this work was to answer the question whether it is possible to detect these modes in real spectroscopic data.
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