An extensive photometric study of the Blazhko RR Lyrae star MW Lyr - II. Changes in the physical parameters

J. Jurcsik, Á Sódor, B. Szeidl, Z. Kolláth, H. A. Smith, Zs Hurta, M. Váradi, A. Henden, I. Dékány, I. Nagy, K. Posztobányi, A. Szing, K. Vida, N. Vityi

Research output: Contribution to journalArticle

28 Citations (Scopus)


The analysis of the multicolour photometric observations of MW Lyr, a large modulation amplitude Blazhko variable, shows for the first time how the mean global physical parameters vary during the Blazhko cycle. About 1-2 per cent changes in the mean radius, luminosity and surface effective temperature are detected. The mean radius and temperature changes are in good accordance with pulsation model results, which show that these parameters do indeed vary within this order of magnitude if the amplitude of the pulsation changes significantly. We interpret the phase modulation of the pulsation to be a consequence of period changes. Its magnitude corresponds exactly what one expects from the detected changes of the mean radius assuming that the pulsation constant remains the same during the modulation. Our results indicate that during the modulation the pulsation remains purely radial, and the underlying mechanism is most probably a periodic perturbation of the stellar luminosity with the modulation period.

Original languageEnglish
Pages (from-to)1553-1562
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
Publication statusPublished - Mar 1 2009



  • Methods: data analysis
  • Stars: horizontal branch
  • Stars: individual: MW Lyr
  • Stars: oscillations
  • Stars: variables: other
  • Techniques: photometric

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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