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New Results of the Konkoly Blazhko Group Johanna Jurcsik Konkoly Observatory

New Results of the Konkoly Blazhko Group Johanna Jurcsik Konkoly Observatory. Santa Fe, 2009, New Mexico, USA Stellar Pulsation: Challenges for Theory and Observation. The Konkoly Blazhko Survey (2003-2009) PIs: J. Jurcsik & B. Szeidl

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New Results of the Konkoly Blazhko Group Johanna Jurcsik Konkoly Observatory

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  1. New Results of the Konkoly Blazhko GroupJohanna Jurcsik Konkoly Observatory Santa Fe, 2009, New Mexico, USA Stellar Pulsation: Challenges for Theory and Observation

  2. The Konkoly Blazhko Survey (2003-2009) PIs: J. Jurcsik & B. Szeidl PhD students: Á. Sódor & Zs. Hurta co-workers: undergraduate/graduate students Aims: To obtain extended, accurate, multicolour light curves of modulated and unmodulated RRab stars in order to • derive the incidence rate of the modulation in the sample • study long term changes in the pulsation and modulation properties • find any changes in the physical parameters of the stars during the Blazhko cycle

  3. Results are obtained utilizing Recent CCD observations obtained with an automatic 60cm telescope Archive Konkoly photometric data spanning over 80 years 24” telescope, Konkoly Observatory, Svábhegy, Budapest

  4. The observed light curves cover the whole pulsation light curve in different phases of the modulation

  5. Multicolour data V – (B-V) V – (V-IC) (B-V) – (V-IC)

  6. Results 1 First detection of small-amplitude, short period modulations mmag amplitudes of the modulation frequency components Jurcsik, Sódor, Váradi et al. 2005, A&A 430, 1049 Jurcsik, Szeidl, Sódor et al. 2006, AJ 132, 61 Jurcsik, Hurta, Sódor et al. 2009, MNRAS in press

  7. SS Cnc Pmod=5.3 d RR Gem Pmod=7.2 d DM Cyg Pmod=10.6 d BR Tau Pmod=19.3 d

  8. Results 2 First systematic survey dedicated to determine the frequency of the occurrence of the modulation Konkoly Blazhko Survey I (0.35d < P < 0.50d) from 30 RRab 14 show the Blazhko effect 47% incidence rate Konkoly Blazhko Survey II (0.55d < P < 0.6d) in progress from 11 RRab 6 show the Blazhko effect 55% incidence rate 50% of RRab stars show the Blazhko effect previous estimates gave 15-30% incidence rate

  9. Results 3 First light curves suitable to study the ‘fine structure’ of the spectrum • detection of quintuplet frequencies in the spectrum of RV UMa Hurta, Jurcsik, Szeidl & Sódor 2008, AJ, 135, 957 • detection of higher modulation multiplets in the spectrum of MW Lyr Jurcsik, Sódor, Hurta et al. 2008, MNRAS 391, 164 • unambiguous detection of fm in the spectra of accurate, extended data of Blazhko stars in all the Konkoly Blazhko data • detection of multiple periodic modulationsSódor et al 2006 Sódor 2009

  10. schematic amplitude spectrum of UZ Vir exponential / linear decrease of the pulsation / modulation components secondary modulation asymmetric triplets quintuplets fm similar amplitudes of the pulsation and modulation components in high orders

  11. Results 4 • temporal occurrence of the modulation • significant changes in the properties of the modulation Sódor, Szeidl, Jurcsik 2007 A&A 469, 1033 Sódor 2009, CoAst 159, 55

  12. RR Geminorum 1935-36 1938-53 1958-59 1965-83 2004-05 amplitude of phase modulation amplitude modulation

  13. RY Comae

  14. CZ Lacertae Pmod1=18.51 d 2005 Pmod2=14.80 d Pm1/Pm2 ≈5/4 Pmod1=18.68 d 2006 Pmod2=14.31 d Pm1/Pm2 ≈4/3

  15. Interpretation 1 Amplitude and phase modulations of a harmonic function describe the observed frequency spectrum of Blazhko stars very well: m(t)=a [1+bsin(Wt+F)] sin[wt+c sin(Wt)] Af0 A(f0±fm) A(f0±2fm) A(f0±3fm) asymmetric amplitudes of the modulation side frequencies occurrence and rapid amplitude decrease of the higher order multiplets of the modulation frequency components (f0± ifm) F Szeidl & Jurcsik, CoAst submitted Phase difference of amplitude and phase modulations

  16. Interpretation 2 Separation of amplitude and phase modulation componets by transforming the data according to the phase variation of f0 Analytically, phase modulationis equivalent with periodic changes of the pulsation period (f0). Jurcsik, Sódor, Hurta et al, 2008, MNRAS 391, 164

  17. Interpretation 3 Our observations and their interpretation indicate that: • the physically meaningful frequency of the Blazhko effect is fm • the pulsation period and the amplitude of the radial mode pulsation change with the modulation period • the global physical parameters of the star (<R>,<L>,<Teff>) vary during the Blazhko cycle Jurcsik, Szeidl, Sódor et al. 2006, AJ 132, 61 Jurcsik Sódor, Szeidl et al, 2009, MNRAS 393, 1553 Jurcsik, Hurta, Sódor et al, 2009, MNRAS in press with the Blazhko cycle periodic, structural changes in the stars occur which result in period and amplitude changes of the pulsation Stothers 2006, ApJ 652, 643 Further theoretical studies are needed to identify the „triggering mechanism” of the Blazhko modulation

  18. Thanks for your attention

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