Line profile variations in classical Cepheids - Evidence for non-radial pulsations?

@article{Kovtyukh2003LinePV,
  title={Line profile variations in classical Cepheids - Evidence for non-radial pulsations?},
  author={Valery V. Kovtyukh and Sergei M. Andrievsky and R. Earle Luck and Nadya I. Gorlova},
  journal={Astronomy and Astrophysics},
  year={2003},
  volume={401},
  pages={661-668}
}
We have investigated line profiles in a large sample of Cepheid spectra, and found four stars that show unusual (for Cepheids) line profile structure (bumps or/and asymmetries). The profiles can be phase dependent but the behavior persists over many cycles. The asymmetries are unlikely to be due to the spectroscopic binarity of these stars or the specific velocity field in their atmospheres caused by shock waves. As a preliminary hypothesis, we suggest that the observed features on the line… 
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