V473 Lyrae, a unique second-overtone Cepheid with two modulation cycles

L. Molnár, L. Szabados

Research output: Contribution to journalArticle

13 Citations (Scopus)


V473 Lyrae is the only Galactic Cepheid with confirmed periodic amplitude and phase variations similar to the Blazhko effect observed in RR Lyrae stars. We collected all available photometric data and some radial velocity measurements to investigate the nature of the modulation. The comparison of the photometric and radial velocity amplitudes confirmed that the star pulsates in the second overtone. The extensive data set, spanning more than 40 years,allowed us to detect a secondary modulation cycle with a period of approximately 5300 d or 14.5 yr. The secondary variations can be detected in the period of the primary modulation, as well. Phenomenologically, the light variations are analogous to the Blazhko effect. To find a physical link, we calculated linear hydrodynamic models to search for potential mode resonances that could drive the modulation and found two viable half-integer (n:2) and three n:4 resonances between the second overtone and other modes. If any of these resonances will be confirmed by non-linear models, it may confirm the mode resonance model, a common mechanism that can drive modulations both in RR Lyrae and Cepheid stars.

Original languageEnglish
Article numberstu1091
Pages (from-to)3222-3234
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
Publication statusPublished - Aug 2014



  • Stars: variables: Cepheids
  • individual: V473 Lyrae

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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