Comparison of the Pulsation Properties of the Rr Lyrae Stars in ω Centauri with those of Classical Cepheids

In the last few years several studies have shown that Fourier decomposition technique is a powerful method for quantitative description of light curves of pulsation variables. This technique was introduced by Simon & Lee (1981), who showed that amplitude ratios and phase differences provide a very useful description of the Hertzsprung progression for classical Cepheids. Recently, Simon & Teays (1982) discussed 70 RR Lyrae field stars.In the present study I analyse 130 photographic mean light curves of RR Lyrae variables in ω Centauri taken from Martin (1938). I wish (i) to compare the Fourier decomposition parameters of the ω Cen RR Lyrae stars with those of the field variables as studied by Simon & Teays, (ii) to discuss the evidence for progression sequences among the ω Cen variables and (iii) to compare the basic pulsation properties of the RRab variables in ω Cen with those of classical Cepheids.

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Fourier Decomposition Parameters for the Halo RR Lyrae Variables U and V Caeli

International Astronomical Union Colloquium ◽

10.1017/s0252921100109509 ◽

1985 ◽

Vol 82 ◽

pp. 272-275

Author(s):

L. Hansen ◽

J. O. Petersen

Keyword(s):

Light Curve ◽

Light Curves ◽

Published Data ◽

Amplitude Ratios ◽

Rr Lyrae Stars ◽

Fourier Decomposition ◽

Rr Lyrae ◽

Lyrae Stars ◽

Phase Differences

AbstractUBVRI light curves are obtained for the two halo RR Lyrae variables U Caeli with period 0.420 days (73 observations) and V Caeli with period 0.571 days (42 observations). It is shown that their light curve characteristics are very similar to those of field RR Lyrae stars.Fourier decompositions are studied for all five magnitudes and the resulting amplitude ratios and phase differences are discussed. The differences in the Fourier decomposition parameters between the five magnitudes are shown to be relatively small. Comparisons of the Fourier decomposition parameters for the two halo RR Lyrae stars with recently published data for field RR Lyrae stars show no systematic differences.

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Theoretical UBVI Light Curves of Pulsating Stars

International Astronomical Union Colloquium ◽

10.1017/s0252921100058012 ◽

2000 ◽

Vol 176 ◽

pp. 334-337

Author(s):

Michael U. Feuchtinger ◽

Ernst A. Dorfi

Keyword(s):

Radiative Transfer ◽

Light Curves ◽

Rr Lyrae Stars ◽

Fourier Decomposition ◽

Pulsating Stars ◽

Rr Lyrae ◽

Stellar Pulsation ◽

Sample Application ◽

Lyrae Stars ◽

Good Agreement

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.

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RR Lyrae in M15: Fourier Decomposition and Physical Parameters

Proceedings of the International Astronomical Union ◽

10.1017/s1743921307006114 ◽

2006 ◽

Vol 2 (S240) ◽

pp. 605-612

Author(s):

G. García Lugo ◽

A. Arellano Ferro ◽

Patricia Rosenzweig

Keyword(s):

Globular Clusters ◽

Light Curves ◽

Physical Parameters ◽

Rr Lyrae Stars ◽

Mean Values ◽

Fourier Decomposition ◽

Rr Lyrae ◽

Blazhko Effect ◽

The Mean ◽

Lyrae Stars

AbstractThe V and R light curves for 30 RR Lyrae stars in M15 were used to calculate their physical parameters. The Blazhko effect, previously reported in V12, was not detected. The determined values of the iron content and distance of the cluster are: [Fe/H] = −1.98 ± 0.24 and d = 8.67 ± 0.41 kpc, respectively. The mean values of the physical parameters determined for the RR Lyrae stars place the cluster precisely into the sequences Oosterhoff type – metallicity and metallicity – effective temperature, valid for globular clusters.

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The Unusual Period Distribution of the RR Lyrae Variables in NGC 5897

International Astronomical Union Colloquium ◽

10.1017/s0252921100011957 ◽

1989 ◽

Vol 111 ◽

pp. 287-287

Author(s):

Amelia Wehlau

Keyword(s):

Light Curves ◽

Instability Strip ◽

Rr Lyrae Stars ◽

Rr Lyrae ◽

Period Distribution ◽

Unusual Distribution ◽

Photoelectric Observations ◽

Lyrae Stars ◽

Branch Star ◽

Central Concentration

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.

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The Period-Radius Relation: Classical Cepheids and RR Lyrae stars

International Astronomical Union Colloquium ◽

10.1017/s0252921100011222 ◽

2004 ◽

Vol 193 ◽

pp. 502-505

Author(s):

M. Marconi ◽

G. Bono ◽

T.E. Nordgren

Keyword(s):

Robust Method ◽

Rr Lyrae Stars ◽

Rr Lyrae ◽

Classical Cepheids ◽

Metal Abundance ◽

Lyrae Stars

Abstract We present the period-radius relations predicted by nonlinear convective models of Classical Cepheids and RR Lyrae stars. For the former variables we show that the metallicity effect is negligible for both fundamental and first overtone pulsators. This confirms the power of the period-radius relation to estimate Cepheid radii and in turn distances. For the latter class of variables we show that the dispersion of the period-radius relation of both fundamental and first overtone pulsators is significantly reduced once the metallicity dependence is taken into account. This provides a robust method to evaluate the radius of observed RR Lyrae with measured period and metal abundance.

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Light Curves and Metal Abundances of RR Lyrae Variables in the Bar of the Large Magellanic Cloud

International Astronomical Union Colloquium ◽

10.1017/s0252921100057481 ◽

2000 ◽

Vol 176 ◽

pp. 172-175 ◽

Cited By ~ 1

Author(s):

G. Clementini ◽

A. Bragaglia ◽

L. Di Fabrizio ◽

E. Carretta ◽

R. G. Gratton

Keyword(s):

Large Magellanic Cloud ◽

Magellanic Cloud ◽

Light Curves ◽

Photometric System ◽

Rr Lyrae Stars ◽

Rr Lyrae ◽

Visual Magnitude ◽

Metal Abundance ◽

Definition Of ◽

Lyrae Stars

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.

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OGLE-ing the Magellanic System: Three-Dimensional Structure

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318007093 ◽

2018 ◽

Vol 14 (S344) ◽

pp. 86-89

Author(s):

Anna M. Jacyszyn-Dobrzeniecka ◽

Keyword(s):

Three Dimensional ◽

Neutral Hydrogen ◽

Variable Stars ◽

Dimensional Structure ◽

Rr Lyrae Stars ◽

Three Dimensional Structure ◽

Rr Lyrae ◽

Classical Cepheids ◽

Lyrae Stars ◽

Magellanic System

AbstractWe present a three-dimensional structure of the Magellanic System using over 9 000 Classical Cepheids and almost 23 000 RR Lyrae stars from the OGLE Collection of Variable Stars. Given the vast coverage of the OGLE-IV data and very high completeness of the sample, we were able to study the Magellanic System in great details.We very carefully studied the distribution of both types of pulsators in the Magellanic Bridge area. We show that there is no evident physical connection between the Clouds in RR Lyrae stars distribution. We only see the two extended structures overlapping. There are few classical Cepheids in the Magellanic Bridge area that seem to form a genuine connection between the Clouds. Their on-sky locations match very well young stars and neutral hydrogen density contours. We also present three-dimensional distribution of classical pulsators in both Magellanic Clouds.

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The effect of stellar evolution on the light curves’ shapes of RR Lyrae stars in M3

International Astronomical Union Colloquium ◽

10.1017/s0252921100010563 ◽

2004 ◽

Vol 193 ◽

pp. 171-175

Author(s):

Johanna Jurcsik

Keyword(s):

Light Curve ◽

Stellar Evolution ◽

Light Curves ◽

Horizontal Branch ◽

Homogeneous Sample ◽

Rr Lyrae Stars ◽

Rr Lyrae ◽

Lyrae Stars

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.

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On the Application of Fourier Decomposition Parameters

International Astronomical Union Colloquium ◽

10.1017/s0252921100014081 ◽

1993 ◽

Vol 134 ◽

pp. 157-158

Author(s):

J. O. Petersen

Keyword(s):

Fourier Analysis ◽

Light Curves ◽

Amplitude Ratios ◽

Fourier Decomposition ◽

Practical Applications ◽

Convincing Argument ◽

Lee Form ◽

Modern Form ◽

Made In ◽

Phase Differences

The application of Fourier decomposition parameters has revolutionized important areas of investigations of Cepheid type variables since the introduction of Fourier analysis in its modern form by Simon and Lee (1981).In the literature several different representations of the results of Fourier analysis have been utilized. In view of the growing interest for applications of Fourier decomposition it is important to use and publish Fourier data in an optimal way. Most studies until now have used amplitude ratios and phase differences derived from traditional light curves giving the light variation in magnitudes, following the original recipe of Simon and Lee (1981). However, Stellingwerf and Donohoe (1986) advocated the use of phases rather than phase differences. Recently, Buchler et al. (1990) argued that the standard Simon & Lee form contains all relevant physics, and suggested analysis of flux-values rather than of magnitudes, because this removes the distorting effects of constant, false light. Thus there are many choices to be made in practical applications of Fourier analysis, and there is at present no convincing argument for preferring one specific representation.

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