The Changing Blazhko Effect of XZ Cygni

Lacluyzé, A.; Smith, Horace A.; Gill, E.-M.; Hedden, Abigail; Kinemuchi, Karen; Rosas, Alexandre; Pritzl, B. J.; Sharpee, B. D.; Wilkinson, Christopher; Robinson, Keith; Baldwin, Marvin E.; Samolyk, G.

doi:10.1086/382101

Cited by 41 publications

(31 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…8, although they can be compared only on the bases of three epochs of data. The data define dP mod /dP puls = 1.6 ± 0.8 × 10 3 for RR Gem, which completes the list of Blazhko stars with measured period change of both their periods (LaCluyzé et al 2004 , Table 8) with a new item.…”

Section: Connections Between the Pulsation And Modulation Propertiesmentioning

confidence: 73%

The Blazhko behaviour of RR Geminorum II

Sódor¹,

Szeidl²,

Jurcsik³

2007

A&A

View full text Add to dashboard Cite

Context. RR Gem is one of the few Blazhko RR Lyrae that has photometric observations available extended enough to study the long-term courses of its pulsation and modulation properties in detail. Aims. We investigate the pulsation and modulation properties and the relations between them in RR Gem using photometric observations from the past 70 years in order to gain further insight into the nature of the Blazhko modulation. Methods. We studied the photographic, photoelectric, and CCD light curves obtained at the Konkoly Observatory and other authors' published maxima observations. Detailed analysis of the light curves, maximum brightness, and O-C data are carried out. Results. RR Gem showed modulation most of the time it was observed. The modulation amplitude showed strong variations from the undetectable level (less than 0.04 mag in maximum brightness) to about 0.20 mag. The amplitudes of the amplitude and phase modulations showed parallel changes, thus the total "power" of the modulation have changed during the past 70 years. Parallel changes in the pulsation and modulation periods occur with a dP mod /dP puls = 1.6 ± 0.8 × 10 3 ratio. We also detected 0.05−0.1 mag changes in the mean maximum brightness and mean pulsation amplitude.

show abstract

Section: Connections Between the Pulsation And Modulation Propertiesmentioning

confidence: 73%

The Blazhko behaviour of RR Geminorum II

Sódor¹,

Szeidl²,

Jurcsik³

2007

A&A

View full text Add to dashboard Cite

show abstract

“…In several well-studied RR Lyrae stars, the amplitude and the period of the Blazhko effect has been observed to be variable on a time-scale of years (Szeidl 1988;Smith et al 1999;LaCluyzé et al 2004). In this respect RR Geminorum provides a very interesting case.…”

Section: Introductionmentioning

confidence: 99%

The Blazhko behaviour of RR Geminorum I

Jurcsik¹,

Sódor

Váradi

et al. 2005

A&A

View full text Add to dashboard Cite

Abstract. Extended CCD monitoring of RR Gem revealed that it is a Blazhko type RRab star with the shortest Blazhko period (7.d 23) and smallest modulation amplitude (∆M max < 0.1 mag) currently known. The short period of the modulation cycle enabled us to obtain complete phase coverage of the pulsation at each phase of the modulation. This is the first multicolour observation of a Blazhko star which is extended enough to define accurate mean magnitudes and colours of the variable at different Blazhko phases. Small, but real, changes in the intensity mean colours at different Blazhko phases have been detected. The Fourier analysis of the light curves shows that, in spite of the mmag and smaller order of the amplitudes, the triplet structure is noticeable up to about the 14th harmonic. The modulation is concentrated to a very narrow, 0.2 phase range of the pulsation, centred on the supposed onset of the H emission during rising light. These observational results raise further complications for theoretical explanation of the long known but poorly understood Blazhko phenomenon.

show abstract

“…Szeidl (1976) also reports stronger and weaker 4-year cycles in the Blazhko effect of RR Lyr. Other well-studied stars also reveal such longer cycles: about 3540 d in XZ Cyg (LaCluyzé et al 2004), about 7200 d in XZ Dra (Jurcsik et al 2002), and between 2000 and 3000 d in RV UMa (Kovacs 1995). In addition, extensive analyses of old and new photometry (same references as above) show that these well-studied stars exhibit coincident changes of both the primary pulsation period and the Blazhko period.…”

Section: Introductionmentioning

confidence: 86%

Observational Constraints on the Magnetic Field of RR Lyrae Stars

Kolenberg¹,

Bagnulo

2009

AIP Conference Proceedings

View full text Add to dashboard Cite

Context. A high percentage of the astrophysically important RR Lyrae stars show a periodic amplitude and/or phase modulation of their pulsation cycles. More than a century after its discovery, this "Blazhko effect" still lacks acceptable theoretical understanding. In one of the plausible models for explaining the phenomenon, the modulation is caused by the effects of a magnetic field. So far, the available observational data have not allowed us to either support nor rule out the presence of a magnetic field in RR Lyrae stars. Aims. We intend to determine whether RR Lyrae stars are generally characterized by the presence of a magnetic field organized on a large scale. Methods. With the help of the FORS1 instrument at the ESO VLT we performed a spectropolarimetric survey of 17 relatively bright southern RR Lyrae stars, both Blazhko stars and non-modulated stars, and determined their mean longitudinal magnetic field with a typical error bar < 30 G. Results. All our measurements of the mean longitudinal magnetic field resulted in null detections within 3 σ. From our data we can set an upper limit for the strength of the dipole component of the magnetic fields of RR Lyrae stars to ∼ 130 G. Because of the limitations intrinsic to the diagnostic technique, we cannot exclude the presence of higher order multipolar components. Conclusions. The outcome of this survey clarifies that the Blazhko modulation in the pulsation of RR Lyrae stars is not correlated with the presence of a strong, quasi-dipolar magnetic field.

show abstract

The Changing Blazhko Effect of XZ Cygni

Cited by 41 publications

References 24 publications

The Blazhko behaviour of RR Geminorum II

The Blazhko behaviour of RR Geminorum II

The Blazhko behaviour of RR Geminorum I

Observational Constraints on the Magnetic Field of RR Lyrae Stars

Contact Info

Product

Resources

About