The Shortest Modulation Period Blazhko RR Lyrae Star: SS Cancri

Jurcsik, J.; Szeidl, B.; Sódor, Á.; Dékány, I.; Hurta, Zs.; Posztobányi, K.; Vida, K.; Váradi, Mihály; Szing, A.

doi:10.1086/504514

Cited by 66 publications

(91 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the corresponding cosine parameter φ (c) 31 is related by φ (s) 31 = φ (c) 31 −π. This equation gives [Fe/H] J with a standard deviation from this calibration of 0.14 dex (Jurcsik 1998 (Jurcsik 1995). We note that the deviation parameter Dm (Jurcsik & Kovacs 1996) for this star when fitting higher-order Fourier series is greater than the recommended value.…”

Section: Rr Lyrae Starsmentioning

confidence: 74%

Variable stars in the globular cluster NGC 7492

Jaimes

Ferro

Bramich

et al. 2013

A&A

View full text Add to dashboard Cite

Aims. We have performed a photometric V, R, I CCD time-series analysis with a baseline of about eight years of the outer-halo globular cluster NGC 7492 with the aim of searching for new variables and using these (and the previously known variables) to determine the physical parameters of interest for the cluster (e.g. metallicity, absolute magnitude of the horizontal branch, distance, etc.). Methods. We used difference image analysis to extract precise light curves in the relatively crowded star field, especially towards the densely populated central region. Several different approaches were used for variability detection that recover the known variables and lead to new discoveries. We determined the physical parameters of the only RR0 star using a light-curve Fourier decomposition analysis. Results. We found one new long-period variable and two SX Phe stars in the blue straggler region. We also present one candidate SX Phe star that requires follow-up observations. Assuming that the SX Phe stars are cluster members and using the period-luminosity relation for these stars, we estimate their distances as ∼25.2 ± 1.8 and 26.8 ± 1.8 kpc, and identify their possible modes of oscillation. We refined the periods of the two RR Lyrae stars in our field of view. We found that the RR1 star V2 is undergoing a period change and possibly exhibits the Blazhko effect. A Fourier decomposition of the light curve of the RR0 star V1 allowed us to estimate a metallicity of [Fe/H] ZW ∼ −1.68 ± 0.10 or [Fe/H] UVES ∼ −1.64 ± 0.13, a log-luminosity log(L/L ) ∼ 1.76 ± 0.02, an absolute magnitude M V ∼ 0.38 ± 0.04 mag, and a true distance modulus of μ 0 ∼ 16.93 ± 0.04 mag, which is equivalent to a distance of ∼24.3 ± 0.5 kpc. All of these values are consistent with previous estimates in the literature.

show abstract

Section: Rr Lyrae Starsmentioning

confidence: 74%

Variable stars in the globular cluster NGC 7492

Jaimes

Ferro

Bramich

et al. 2013

A&A

View full text Add to dashboard Cite

show abstract

“…Such a discrepancy of 0.3-0.5 dex seems to be present also in other lowmetallicity clusters. For example, for the RRab stars of M68 we find [Fe/H] = −1.8 (Jurcsik & Kovács 1996), whereas the highdispersion spectroscopic data on giants by Lee et al (2005) suggest a value of −2.2 dex (both values are on the scale of Jurcsik 1995). Similarly, for the RRab stars of NGC 5053, Nemec (2004) finds [Fe/H] = −1.7, whereas the low-dispersion spectral indices of Suntzeff et al (1988) yield −2.3 dex for the giants.…”

Section: Discussionmentioning

confidence: 93%

“…By using their Eq. (3) and transforming the values to the scale of Jurcsik (1995), we find an average [Fe/H] of −1.68 ± 0.08 (error of the mean) for the sample of 15 stars (for two stars, data were taken from Kopacki 2000). Although this value confirms the one derived from the RRab population, we note the following: (i) the structure of the RRc light curves contain fewer distinct features than those of the RRab stars and even these are often washed out by noise; (ii) the calibration for the RRc stars is based on cluster variables that, because of the absence of individual metallicity estimates, are assumed to have the same metallicity as that of the host cluster (i.e., there are 12 independent metallicity values used in the regression for the 106 variables in the calibrating sample); because of the use of cluster variables, the full span of the metallicity range is only [−1.0, −2.2], that is nearly a factor of two smaller than the one used by JK96 for the Galactic field RRab stars.…”

Section: [Fe/h] Distributionmentioning

confidence: 99%

Study of globular cluster M53: new variables, distance, metallicity

Dékány

Kovács

2009

A&A

Self Cite

View full text Add to dashboard Cite

Aims. We study the variable star content of the globular cluster M53 to compute the physical parameters of the constituting stars and the distance of the cluster. Methods. Covering two adjacent seasons in 2007 and 2008, new photometric data are gathered for 3048 objects in the field of M53. By using the OIS (optimal image subtraction) method and subsequently TFA (trend filtering algorithm), we search for variables in the full sample by using discrete Fourier transformation and box-fitting least squares methods. We select variables based on the statistics related to these methods combined with visual inspection. Results. We identified 12 new variables (2 RR Lyrae stars, 7 short periodic stars -3 of them are SX Phe stars -and 3 long-period variables). No eclipsing binaries were found in the present sample. Except for the 3 (hitherto unknown) Blazhko RR Lyrae (two RRab and an RRc) stars, no multiperiodic variables were found. We showed that after proper period shift, the PLC (period-luminositycolor) relation for the first overtone RR Lyrae sample tightly follows the one spanned by the fundamental stars. Furthermore, the slope is in agreement with that derived from other clusters. Based on the earlier Baade-Wesselink calibration of the PLC relations, the derived reddening-free distance modulus of M53 is 16.31 ± 0.04 mag, corresponding to a distance modulus of 18.5 mag for the Large Magellanic Cloud. From the Fourier parameters of the RRab stars we obtained an average iron abundance of −1.58 ± 0.03 (error of the mean). This is ∼0.5 dex higher than the overall abundance of the giants as given in the literature and derived in this paper from the three-color photometry of giants. We suspect that the source of this discrepancy (observable also in other, low-metallicity clusters) is the lack of a sufficient number of low-metallicity objects in the calibrating sample of the Fourier method.

show abstract

“…The appearance of the Blazhko modulation frequency f m itself was a long-standing debate. However, it has always been detected in the spectra of extended enough photometric data sets (Kovács 1995;Nagy 1998;Jurcsik et al 2005Jurcsik et al , 2006Jurcsik et al , 2008Jurcsik et al , 2009). In the case of MW Lyr it was found together with its first harmonics 2 f m .…”

Section: Frequency Analysismentioning

confidence: 99%

First CoRoT light curves of RR Lyrae stars

Chadid¹,

Benkő

Szabo

et al. 2010

A&A

View full text Add to dashboard Cite

Context. The CoRoT -Convection Rotation and planetary Transits -space mission is a great opportunity for monitoring stars with excellent time-sampling and unprecedented photometric precision for up to 150 days. As an important benefit, high-quality RR Lyrae light curves are obtained with a quasi-uninterrupted coverage over several pulsation and Blazhko cycles. Aims. The Blazhko effect in RR Lyrae stars is an unsolved problem of astrophysics. We used the high-precision space data to contribute more precise knowledge to explain the possible physical processes behind the phenomenon. Methods. We applied different period-finding techniques including Period04, MuFrAn, PDM and SigSpec. Amplitude and phase modulation were investigated by an analytical function method as well as with the traditional O-C diagrams. Results. The Blazhko modulation frequency is directly detected in the spectrum, as well as its first and second harmonics. It shows the non-linear nature of the Blazhko modulation. Besides the triplets, further higher-order modulation side peaks appear around the pulsation frequency as quintuplet, septuplet, nonuplet, undecaplet, tredecaplet, quindecaplet and sepdecaplet structures. Additional frequencies, not belonging to the classical multiplet structures, are detected, as well as their linear combinations with the fundamental radial mode. We interpret these additional terms as non-radial modes. During the five consecutive Blazhko cycles, there is a shift of the maximum phase around 0.011 pulsation phase which is likely the consequence of a long term modulation.

show abstract

The Shortest Modulation Period Blazhko RR Lyrae Star: SS Cancri

Cited by 66 publications

References 14 publications

Variable stars in the globular cluster NGC 7492

Variable stars in the globular cluster NGC 7492

Study of globular cluster M53: new variables, distance, metallicity

First CoRoT light curves of RR Lyrae stars

Contact Info

Product

Resources

About