scholarly journals CoRoT light curves of Blazhko RR Lyrae stars

2011 ◽  
Vol 527 ◽  
pp. A146 ◽  
Author(s):  
M. Chadid ◽  
C. Perini ◽  
G. Bono ◽  
M. Auvergne ◽  
A. Baglin ◽  
...  
1989 ◽  
Vol 111 ◽  
pp. 287-287
Author(s):  
Amelia Wehlau

AbstractAttention is called to the rather unusual distribution of the periods of the RR Lyrae variables in NGC 5897, a metal-poor halo globular cluster with a very low central concentration. Of the seven RR Lyrae stars known in the cluster, three have periods between 0.797 and 0.856 day and two have periods of 0.45 and 0.42 day. The other two have periods of 0.34 and 0.35 day with much lower amplitudes of variation. Due to the lack of crowding in this cluster photoelectric observations and Fourier decompositions of the resulting light curves should be possible for at least six of the RR Lyrae variables. In addition, the cluster appears to contain a non-variable horizontal branch star, SK 120, lying within the instability strip. As this is the only well documented case of such a star, photoelectric observations of this star would also be desirable.


2000 ◽  
Vol 176 ◽  
pp. 172-175 ◽  
Author(s):  
G. Clementini ◽  
A. Bragaglia ◽  
L. Di Fabrizio ◽  
E. Carretta ◽  
R. G. Gratton

AbstractThe Large Magellanic Cloud (LMC) is widely considered a corner-stone of the astronomical distance scale. However, a difference of 0.2−0.3 mag exists in its distance as predicted by the short and long distance scales. Distances to the LMC from Population II objects are founded on the RR Lyrae variables. We have undertaken an observational campaign devoted to the definition of the average apparent luminosity, and to the study of the mass–metallicity relation for RR Lyrae stars in the bar of the LMC. These are compared with analogous quantities for cluster RR Lyrae stars. The purpose is to see whether an intrinsic difference in luminosity, possibly due to a difference in mass, might exist between field and cluster RR Lyrae stars, which could be responsible for the well-known dichotomy between short and long distance scales. Preliminary results are presented on the V and B − V light curves, the average apparent visual magnitude, and the pulsational properties of 102 RR Lyrae stars in the bar of the LMC, observed at ESO in January 1999. The photometric data are accurately tied to the Johnson photometric system. Comparison is presented with the photometry of RR Lyrae stars in the bar of the LMC obtained by the MACHO collaboration (Alcock et al. 1996). Our sample includes 9 double-mode RR Lyrae stars selected from Alcock et al. (1997) for which an estimate of the metal abundance from the ΔS method is presented.


2004 ◽  
Vol 193 ◽  
pp. 171-175
Author(s):  
Johanna Jurcsik

AbstractThe light curve characteristics of a homogeneous sample of variables in M3 are studied in detail. Accurate light curves and mean magnitudes of about 100 RRab and 50 RRc stars which do not show any type of modulation are analyzed. According to their mean magnitudes and Fourier parameters the variables can be sorted into four groups, representing different stages of the horizontal branch stellar evolution.


2000 ◽  
Vol 176 ◽  
pp. 334-337
Author(s):  
Michael U. Feuchtinger ◽  
Ernst A. Dorfi

AbstractBy performing detailed frequency-dependent radiative transfer computations we are able to calculate light curves in particular bandpasses from stellar pulsation models calculated by the Vienna nonlinear convective pulsation code. As a sample application we discuss UBVI light curves of RR Lyrae stars. The properties of these light curves are analyzed by means of standard Fourier decomposition, and a comparison to recent observations is performed. As main results we find a good agreement with important observed RR Lyrae properties like pulsation amplitudes and Fourier parameters in B, V, and I bands. Additionally, from the synthetic color curves we derive linear transformation laws between amplitudes as well as Fourier parameters in the different bandpasses.


1992 ◽  
Vol 104 ◽  
pp. 159 ◽  
Author(s):  
Jesper Storm ◽  
Bruce W. Carney ◽  
David W. Latham

2020 ◽  
Vol 635 ◽  
pp. A66 ◽  
Author(s):  
Z. Prudil ◽  
I. Dékány ◽  
R. Smolec ◽  
M. Catelan ◽  
E. K. Grebel ◽  
...  

We present the most extended and homogeneous study carried out so far of the main and early shocks in 1485 RR Lyrae stars in the Galactic bulge observed by the Optical Gravitational Lensing Experiment. We selected nonmodulated fundamental-mode RR Lyrae stars with good-quality photometry. Using a self-developed method, we determined the centers and strengths of main and early shock features in the phased light curves. We found that the positions of both humps and bumps are highly correlated with the pulsation properties of the studied variables. Pulsators with a pronounced main shock are concentrated in the low-amplitude regime of the period–amplitude diagram, while stars with a strong early shock have average and above-average pulsation amplitudes. A connection between the main and early shocks and the Fourier coefficients is also observed. In the color–magnitude diagram, we see a separation between stars with strong and weak shocks. Variables with a pronounced main shock cluster close to the fundamental red edge of the instability strip (IS), while stars with a strong early shock tend to clump in the center and near the fundamental blue edge of the IS. The appearance of shocks and their properties appear to be independent of the direction of evolution estimated from the period change rate of the studied stars. In addition, the differences in the period change rate between the two main Oosterhoff groups found in the Galactic bulge suggest that stars of Oosterhoff type I are located close to the zero-age horizontal branch while Oosterhoff type II variables are on their way toward the fundamental red edge of the instability strip, and have therefore already left the zero-age horizontal branch.


1975 ◽  
Vol 67 ◽  
pp. 553-553
Author(s):  
G. H. Chis ◽  
V. Ureche

Observations of some RR Lyrae stars with varying periods and shapes of the light curves were discussed. These are:TU Com (Ureche, V., 1965)WY Dra (Chis, D., Chis, G. H., and Mihoc, I. (1974))SW Psc (Ureche, V. (1971a, b))


2006 ◽  
Vol 453 (3) ◽  
pp. 895-902 ◽  
Author(s):  
C. Wu ◽  
Y. L. Qiu ◽  
J. S. Deng ◽  
J. Y. Hu ◽  
Y. H. Zhao

2018 ◽  
Vol 614 ◽  
pp. L4 ◽  
Author(s):  
Geza Kovacs

We analyzed 151 variables previously classified as fundamental mode RR Lyrae stars from Campaigns 01–04 of the Kepler two-wheel (K2) archive. By employing a method based on the application of systematics filtering with the aid of co-trending light curves in the presence of a large amplitude signal component, we searched for additional Fourier signals in the close neighborhood of the fundamental period. We found only 13 stars without such components, yielding the highest rate of modulated (Blazhko) stars detected so far (91 %). A detection efficiency test suggests that this occurrence rate likely implies a 100 % underlying rate. Furthermore, the same test performed on a subset of the Large Magellanic Cloud RR Lyrae stars from the MACHO archive shows that the conjecture of high true occurrence rate fits well to the low observed rate derived from this database.


2013 ◽  
Vol 9 (S301) ◽  
pp. 427-428 ◽  
Author(s):  
Young-Beom Jeon ◽  
Chow-Choong Ngeow ◽  
James M. Nemec

AbstractFollow-up (U)BVRI photometric observations have been carried out for 42 RR Lyrae stars in the Kepler field. The new magnitude and color information will complement the available extensive high-precision Kepler photometry and recent spectroscopic results. The photometric observations were made with the following telescopes: 1-m and 41-cm telescopes of Lulin Observatory (Taiwan), 81-cm telescope of Tenagra Observatory (Arizona, USA), 1-m telescope at the Mt. Lemmon Optical Astronomy Observatory (LOAO, Arizona, USA), 1.8-m and 15-cm telescopes at the Bohyunsan Optical Astronomy Observatory (BOAO, Korea) and 61-cm telescope at the Sobaeksan Optical Astronomy Observatory (SOAO, Korea). The observations span from 2010 to 2013, with ~200 to ~600 data points per light curve. Preliminary results of the Korean observations were presented at the 5th KASC workshop in Hungary. In this work, we analyze all observations. These observations permit the construction of full light curves for these RR Lyrae stars and can be used to derive multi-filter Fourier parameters.


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