New Results of the New Results of the Konkoly Blazhko GroupKonkoly Blazhko Group

Johanna JurcsikJohanna Jurcsik Konkoly Observatory Konkoly Observatory

Santa Fe, 2009, New Mexico, USASanta Fe, 2009, New Mexico, USAStellar Pulsation: Challenges for Theory and ObservationStellar Pulsation: Challenges for Theory and Observation

The Konkoly Blazhko Survey (2003-The Konkoly Blazhko Survey (2003-2009)2009)

PIs: PIs: J. Jurcsik & B. SzeidlJ. Jurcsik & B. Szeidl PhD students: PhD students: Á. Sódor & Zs. HurtaÁ. Sódor & Zs. Hurta co-workers: co-workers: undergraduate/graduate undergraduate/graduate

studentsstudents

Aims:Aims:To obtain extended, accurate, To obtain extended, accurate, multicolour multicolour light light

curvescurvesof modulated and unmodulated RRab starsof modulated and unmodulated RRab stars in order toin order to• derive the incidence rate of the modulation in derive the incidence rate of the modulation in the samplethe sample• study long term changes in the pulsation and study long term changes in the pulsation and

modulation properties modulation properties• find any changes in the physical parameters find any changes in the physical parameters

of the stars during the Blazhko cycle of the stars during the Blazhko cycle

24” telescope, Konkoly Observatory, 24” telescope, Konkoly Observatory, Svábhegy, BudapestSvábhegy, Budapest

Results are obtained Results are obtained utilizingutilizing

• Recent CCD Recent CCD observations obtained observations obtained with an automatic 60cm with an automatic 60cm telescopetelescope

• Archive Konkoly Archive Konkoly photometric data photometric data spanning over 80 yearsspanning over 80 years

The observed light curves cover the The observed light curves cover the whole whole pulsation light curvepulsation light curve in different phases of the in different phases of the modulationmodulation

Multicolour dataMulticolour data

V – (B-V)V – (B-V)

V – (V-IV – (V-ICC))

(B-V) – (V-I(B-V) – (V-ICC))

Results 1Results 1

First detection of small-amplitude, First detection of small-amplitude, short period short period

modulationsmodulations mmag amplitudes of the modulation mmag amplitudes of the modulation frequency componentsfrequency components

Jurcsik, Sódor, Váradi et al. 2005, A&A 430, 1049Jurcsik, Sódor, Váradi et al. 2005, A&A 430, 1049Jurcsik, Szeidl, Sódor et al. 2006, AJ 132, 61Jurcsik, Szeidl, Sódor et al. 2006, AJ 132, 61Jurcsik, Hurta, Sódor et al. 2009, MNRAS in press Jurcsik, Hurta, Sódor et al. 2009, MNRAS in press

SS Cnc PSS Cnc Pmodmod=5.3 d RR Gem P=5.3 d RR Gem Pmodmod=7.2 d=7.2 d

DM Cyg PDM Cyg Pmodmod=10.6 d BR Tau P=10.6 d BR Tau Pmodmod=19.3 d=19.3 d

Results 2Results 2 First systematic survey dedicated First systematic survey dedicated to determine the frequency of the to determine the frequency of the occurrence of the modulation occurrence of the modulation Konkoly Blazhko Survey I (0.35d < P < 0.50d)Konkoly Blazhko Survey I (0.35d < P < 0.50d) from 30 RRab 14 show the Blazhko effectfrom 30 RRab 14 show the Blazhko effect 47% incidence rate47% incidence rate Konkoly Blazhko Survey II (0.55d < P < 0.6d) Konkoly Blazhko Survey II (0.55d < P < 0.6d) in in progressprogress from 11 RRab 6 show the Blazhko effect from 11 RRab 6 show the Blazhko effect 55% incidence rate55% incidence rate

50% of RRab stars show the Blazhko 50% of RRab stars show the Blazhko effecteffect previous estimates gave 15-30% incidence previous estimates gave 15-30% incidence raterate

• 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 modulations Sódor et al 2006 Sódor 2009

Results 3Results 3First light curves suitable to study the First light curves suitable to study the ‘ ‘fine structure’ of the spectrumfine structure’ of the spectrum

exponential / linear decrease of exponential / linear decrease of thethe

pulsation / modulation pulsation / modulation componentscomponents

ffmm

asymmetric asymmetric triplets triplets quintupletquintupletss

schematic amplitude spectrum of UZ Vir schematic amplitude spectrum of UZ Vir

similar amplitudes of the pulsation similar amplitudes of the pulsation and modulation components in high and modulation components in high

ordersorders

secondary modulationsecondary modulation

Results 4Results 4

• temporal occurrence of the temporal occurrence of the modulationmodulation

• significant changes in the significant changes in the properties of the modulation properties of the modulation

Sódor, Szeidl, Jurcsik 2007 A&A 469, 1033Sódor, Szeidl, Jurcsik 2007 A&A 469, 1033 Sódor 2009, CoAst 159, 55Sódor 2009, CoAst 159, 55

RR GeminorumRR Geminorum

1935-36 1938-53 1958-59 1965-83 1935-36 1938-53 1958-59 1965-83 2004-052004-05

amplitude amplitude ofof

phasephasemodulationmodulation

amplitude amplitude modulationmodulation

RY ComaeRY Comae

CZ LacertaeCZ Lacertae PPmod1mod1=18.51 d =18.51 d 2005 2005 P Pmod2mod2=14.80 d=14.80 d

PPmod1mod1=18.68 d =18.68 d 2006 2006 P Pmod2mod2=14.31 d=14.31 d

PPm1m1/P/Pm2 m2 ≈≈ 5/45/4

PPm1m1/P/Pm2 m2 ≈≈ 4/34/3

Interpretation 1Interpretation 1Amplitude and phase modulations of a harmonic functionAmplitude and phase modulations of a harmonic function

describe the observed frequency spectrum of Blazhko describe the observed frequency spectrum of Blazhko starsstars

very well:very well:

asymmetric amplitudes asymmetric amplitudes ofof

the modulation sidethe modulation sidefrequenciesfrequencies

occurrence and rapid occurrence and rapid amplitude decrease of amplitude decrease of

thethehigher order multiplets higher order multiplets

of of the modulation the modulation

frequencyfrequency

components (fcomponents (f00 if ifmm))

m(t)=m(t)=a a [1+[1+bbsinsint+t+sinsinttc c sinsintt

AfAf00

A(fA(f00ffmm))

A(fA(f002f2fmm

))

A(fA(f003f3fmm

)) Szeidl & Jurcsik, CoAst submittedSzeidl & Jurcsik, CoAst submitted

Phase difference of amplitude and phase modulationsPhase difference of amplitude and phase modulations

Interpretation 2Interpretation 2

Jurcsik, Sódor, Hurta et al, 2008, MNRAS Jurcsik, Sódor, Hurta et al, 2008, MNRAS 391, 164391, 164

Separation of amplitude and phase Separation of amplitude and phase modulationmodulationcomponetscomponets by transforming the data by transforming the data according to the phase variation of faccording to the phase variation of f00

Analytically, phase modulationAnalytically, phase modulation is is equivalent withequivalent with periodic changes of the pulsation period periodic changes of the pulsation period (f(f00).).

Interpretation 3Interpretation 3 Our observations and their interpretation indicate Our observations and their interpretation indicate

that:that:• the physically meaningful frequency of the the physically meaningful frequency of the Blazhko effect is fBlazhko effect is fm m

• the pulsation period and the amplitude of the the pulsation period and the amplitude of the radial mode pulsation change with the radial mode pulsation change with the modulation periodmodulation period

• the global physical parameters of the star the global physical parameters of the star (<R>,<L>,<Teff>) vary during the Blazhko (<R>,<L>,<Teff>) vary during the Blazhko cyclecycle

Jurcsik, Szeidl, Sódor et al. 2006, AJ 132, 61Jurcsik, Szeidl, Sódor et al. 2006, AJ 132, 61 Jurcsik Sódor, Szeidl et al, 2009, MNRAS Jurcsik Sódor, Szeidl et al, 2009, MNRAS

393, 1553393, 1553 Jurcsik, Hurta, Sódor et al, 2009, MNRAS in Jurcsik, Hurta, Sódor et al, 2009, MNRAS in

presspress

with the Blazhko cycle periodic, structural changes with the Blazhko cycle periodic, structural changes in the in the

stars occur which result in period and amplitude stars occur which result in period and amplitude changes changes

of the pulsationof the pulsation Stothers 2006, ApJ 652, Stothers 2006, ApJ 652,

643643 Further theoretical studies are needed to Further theoretical studies are needed to

identify theidentify the „ „triggering mechanism” of the Blazhko triggering mechanism” of the Blazhko

modulation modulation

Thanks for your attentionThanks for your attention