The Konkoly Blazhko Survey: Is light-curve modulation a common property of RRab stars?

J. Jurcsik, Á Sódor, B. Szeidl, Z. Hurta, M. Váradi, K. Posztobányi, K. Vida, G. Hajdu, Z. Kővári, I. Nagy, L. Molnár, B. Belucz

Research output: Contribution to journalArticle

85 Citations (Scopus)

Abstract

A systematic survey to establish the true incidence rate of Blazhko modulation among short-period, fundamental-mode, Galactic field RR Lyrae stars has been carried out. The Konkoly Blazhko Survey (KBS) was initiated in 2004. Since then, more than 750 nights of observation have been devoted to this project. A sample of 30 RRab stars was extensively observed, and light-curve modulation was detected in 14 cases. The 47 per cent occurrence rate of the modulation is much larger than any previous estimate. The significant increase of the detected incidence rate is mostly a result of the discovery of small-amplitude modulation. Half of the Blazhko variables in our sample show the modulation with such a small amplitude that they would definitely have been missed in previous surveys. We have found that the modulation can be very unstable in some cases; for example, RY Com showed regular modulation during only one part of the observations, and had a stable light curve with abrupt, small changes in the pulsation amplitude during two observing seasons. This type of light-curve variability is hard to detect in the data from other surveys. The higher frequency of the light-curve modulation of RRab stars makes it even more important to find an explanation for the Blazhko phenomenon. The validity of the [Fe/H](P, φ31) relationship using the mean light curves of Blazhko variables is checked in our sample. We found that the formula gives accurate result for small-modulation-amplitude Blazhko stars, and this is also the case for large-modulation-amplitude stars if the light curve has complete phase coverage. However, if the data for large-modulation-amplitude Blazhko stars are not extended enough (e.g. fewer than 500 data points from fewer than 15 nights), the formula may give false result owing to the distorted shape of the mean light curve used.

Original languageEnglish
Pages (from-to)1006-1018
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Volume400
Issue number2
DOIs
Publication statusPublished - Dec 2009

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common property resource
light curve
modulation
stars
night
incidence
occurrences
estimates
rate

Keywords

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

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

The Konkoly Blazhko Survey : Is light-curve modulation a common property of RRab stars? / Jurcsik, J.; Sódor, Á; Szeidl, B.; Hurta, Z.; Váradi, M.; Posztobányi, K.; Vida, K.; Hajdu, G.; Kővári, Z.; Nagy, I.; Molnár, L.; Belucz, B.

In: Monthly Notices of the Royal Astronomical Society, Vol. 400, No. 2, 12.2009, p. 1006-1018.

Research output: Contribution to journalArticle

Jurcsik, J. ; Sódor, Á ; Szeidl, B. ; Hurta, Z. ; Váradi, M. ; Posztobányi, K. ; Vida, K. ; Hajdu, G. ; Kővári, Z. ; Nagy, I. ; Molnár, L. ; Belucz, B. / The Konkoly Blazhko Survey : Is light-curve modulation a common property of RRab stars?. In: Monthly Notices of the Royal Astronomical Society. 2009 ; Vol. 400, No. 2. pp. 1006-1018.
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AU - Sódor, Á

AU - Szeidl, B.

AU - Hurta, Z.

AU - Váradi, M.

AU - Posztobányi, K.

AU - Vida, K.

AU - Hajdu, G.

AU - Kővári, Z.

AU - Nagy, I.

AU - Molnár, L.

AU - Belucz, B.

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