General Catalogue of Variable Stars: Modern Trends

Samus, N. N.; Kazarovets, E. V.; Durlevich, O. V.

doi:10.1515/astro-2000-0419

Cited by 42 publications

(44 citation statements)

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“…The pulsation period of more than 70 Cepheids in our sample differs from the value given in the GCVS (Samus et al 2004) to the third decimal place. Evolutionary or other secular period changes result in differences smaller than two thousandth parts of the period with respect to the catalogued value decades ago.…”

Section: Pulsation Periodcontrasting

confidence: 80%

Observational studies of Cepheid amplitudes

Klagyivik

Szabados

2009

A&A

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Context. The dependence of amplitude on the pulsation period differs from other Cepheid-related relationships. Aims. We attempt to revise the period-amplitude (P-A) relationship of Galactic Cepheids based on multi-colour photometric and radial velocity data. Reliable P-A graphs for Galactic Cepheids constructed for the U, B, V, R C , and I C photometric bands and pulsational radial velocity variations facilitate investigations of previously poorly studied interrelations between observable amplitudes. The effects of both binarity and metallicity on the observed amplitude, and the dichotomy between short-and long-period Cepheids can both be studied. Methods. A homogeneous data set was created that contains basic physical and phenomenological properties of 369 Galactic Cepheids. Pulsation periods were revised and amplitudes were determined by the Fourier method. P-A graphs were constructed and an upper envelope to the data points was determined in each graph. Correlations between various amplitudes and amplitude-related parameters were searched for, using Cepheids without known companions. Results. Large amplitude Cepheids with companions exhibit smaller photometric amplitudes on average than solitary ones, as expected, while s-Cepheids pulsate with an arbitrary (although small) amplitude. The ratio of the observed radial velocity to blue photometric amplitudes, A V RAD /A B , is not as good an indicator of the pulsation mode as predicted theoretically. This may be caused by an incorrect mode assignment to a number of small amplitude Cepheids, which are not necessarily first overtone pulsators. The dependence of the pulsation amplitudes on wavelength is used to identify duplicity of Cepheids. More than twenty stars previously classified as solitary Cepheids are now suspected to have a companion. The ratio of photometric amplitudes observed in various bands confirms the existence of a dichotomy among normal amplitude Cepheids. The limiting period separating short-and long-period Cepheids is 10.47 days. Conclusions. Interdependences of pulsational amplitudes, the period dependence of the amplitude parameters, and the dichotomy have to be taken into account as constraints in modelling the structure and pulsation of Cepheids. Studies of the P-L relationship must comply with the break at 10. d 47 instead of the currently used "convenient" value of 10 days.

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Section: Pulsation Periodcontrasting

confidence: 80%

Observational studies of Cepheid amplitudes

Klagyivik

Szabados

2009

A&A

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“…The most conspicuous object is the bright star V1421D, which corresponds to Sandage's variable (SV19). According to Sandage (1971) it presents classification problems; the light curve does not repeat perfectly from cycle to cycle, but the period appears to be relatively stable, 446 d. Our data confirm this period, and the V − I value indicates that the star is very red. According to Sandage (1971) the B amplitude is about 2.6 mag, while our data indicate a W h amplitude of about 2.3 mag.…”

Section: Other Variable Starssupporting

confidence: 51%

Variable stars in nearby galaxies

Mantegazza

Antonello

Fugazza

et al. 2001

A&A

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Abstract. The nearby galaxies IC 1613 and NGC 6822 were observed over four years to detect short period Cepheids and to obtain good light curves for Fourier decomposition. The program was carried out with a relatively small telescope, the Dutch 0.9 m at ESO-La Silla, and the observations were performed without filter (white light), or W h-band. In this paper we present the results of the observations of Fields C and D in IC 1613 (3. 8 × 3. 8 each). The analysis of the light curves of 3297 stars in the two fields has allowed the detection of 92 variable stars. A total of 34 Population I Cepheids have been found, while only 7 of these objects were previously known in these fields. Most of the stars have short periods and some of them are first overtone mode pulsators. Among the other variable stars there are one eclipsing binary and five W Vir candidates. A nova event was observed in Field D.

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“…The basic set of the stars originated in the GCVS catalog (Samus et al 2012), which contains 512 stars of RRab type brighter than 12.5 mag in maximum. This magnitude limit was chosen to analyse only stars with the best data quality -the scattering of data points over 13 mag rapidly increases.…”

Section: Sample Selection and Data Cleaningmentioning

confidence: 99%

“…RZ Cet, RV Sex, V413 Oph, BB Vir, SW Cru, V Ind, and Z Mic were only proposed to show modulation with no amplitude or period of modulation determined (Kovács 2005;Samus et al 2012;For et al 2011;Jurcsik & Kovács 1996). Either they are stable or their modulation is of low amplitude.…”

Section: Known Blazhko Starsmentioning

confidence: 99%

Bright Blazhko RRab Lyrae stars observed by ASAS and the SuperWASP surveys

Skarka

2014

A&A

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Aims. Period study of 321 fundamental mode RR Lyrae type stars (RRab), which had appropriate data in ASAS and SuperWASP surveys, was performed to complement and extend the list of known Blazhko stars in galactic field with bright stars up to 12.5 mag in maximum light.Methods. An individual approach was applied to each studied star. Permanent visual supervision was maintained to each procedure in data analysis (data cleaning, frequency spectra examination) to avoid missing any possible sign of the Blazhko effect. Period analysis was performed using Period04 software. Results. We found 100 stars to be definitely modulated. In 25 cases, previously unknown modulation was revealed and 8 new candidates for Blazhko stars were identified. Their modulation needs to be confirmed. In 18 previously found Blazhko stars, no modulation was detectable. Multiple modulation was revealed for eight stars that were previously proposed to show simple modulation. In total, there were twelve stars with some peculiarity in their modulation in the sample. This brings the incidence rate of multiple/irregularlymodulated stars to 12%. The ratio of the modulation periods of five of the double-modulated stars was within the ratios of small integers. One of stars studied, IK Hya, showed a very interesting frequency spectrum, which we interpret as changing Blazhko period between 71.81 and 75.57 days and an additional 1403-day-long cycle analogous to a four-year cycle of the prototype RR Lyr. The limits of the shorter period produce a beating period that is approximately twice as big as a 1403-day period. The newly revealed Blazhko star RZ CVn seems to undergo changes in the amplitude of the modulation, as well as in the basic pulsation and Blazhko periods. We found that the incidence rate of the Blazhko RR Lyraes is at least 31%, more likely even higher. It was also found that the majority of the Blazhko variables show triplet structures in their frequency spectra and that in 89% of these cases, the peak with larger amplitude is on the right-hand side of the main pulsation component.

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General Catalogue of Variable Stars: Modern Trends

Cited by 42 publications

References 0 publications

Observational studies of Cepheid amplitudes

Observational studies of Cepheid amplitudes

Variable stars in nearby galaxies

Bright Blazhko RRab Lyrae stars observed by ASAS and the SuperWASP surveys

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