On the Sandage period shift effect among field RR Lyrae stars

1990 ◽  
Vol 363 ◽  
pp. 159 ◽  
Author(s):  
Young-Wook Lee
Keyword(s):  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
Period Shift ◽  
Shift Effect ◽  
Lyrae Stars

scholarly journals CCD Photometry of RR Lyrae Stars in M3

1993 ◽  
Vol 139 ◽  
pp. 325-331
Author(s):  
C. Cacciari ◽  
E. Carretta ◽  
F. Ferraro ◽  
F. Fusi Pecci ◽  
G. Tessicini ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Ccd Photometry ◽  
Rr Lyrae Stars ◽  
Preliminary Results ◽  
Rr Lyrae ◽  
Period Shift ◽  
Shift Effect ◽  
Lyrae Stars

AbstractNew CCD BVI observations of RR Lyrae variables in M3 are presented. Mean magnitudes and colours are derived, as well as their relations with periods and amplitudes, and comparisons are made with previous data (Sandage 1981, 1990). Preliminary results are presented on the temperature distribution of the variables and the period-shift effect with respect to M15 and M68.

scholarly journals RR Lyrae Stars and the Sandage Period-Shift Effect Examined Using IR-Derived Temperatures

1989 ◽  
Vol 111 ◽  
pp. 274-274
Author(s):  
A.J. Longmore ◽  
R. Dixon ◽  
I. Skillen ◽  
R.F. Jameson ◽  
J.A. Fernley
Keyword(s):  
Globular Clusters ◽  
Log P ◽  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
Period Shift ◽  
Observational Errors ◽  
Shift Effect ◽  
Few Data ◽  
Lyrae Stars ◽  
Temperature Amplitude

AbstractMean temperatures for RR Lyrae stars in 7 globular clusters (M3, M4, M5, M15, M107, ω Cen and NGC 5466) have been determined using the optical-infrared colour <V>-<K> as a temperature indicator. Where <K> has been relatively well determined, from means of 3 or more observations, the scatter in relationships such as Log P’ vs log (temperature) and log (temperature) vs (blue amplitude) is significantly reduced when IR-derived temperatures are used instead of those derived from (B-V). Within the observational errors, the gradient in the log P’ vs log (temperature) diagram is the same for each cluster. Temperatures derived from <V>-<K> should also be less sensitive to metallicity differences than their optically derived counterparts. The Sandage Period-Shift Effect has therefore been re-examined using 6 of the 7 clusters (NGC 5466 was excluded because of too few data). A strong correlation between period-shift and metallicity is found; a smaller shift (but in the same sense) is also found for the temperature – amplitude relationship.

scholarly journals Double-mode RR lyrae stars in the Draco dwarf galaxy and in other stellar systems

1984 ◽  
Vol 105 ◽  
pp. 465-466 ◽  
Author(s):  
James M. Nemec
Keyword(s):  
Dwarf Galaxy ◽  
Mass Loss Rate ◽  
The Other ◽  
Mode Switching ◽  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
Period Shift ◽  
Blazhko Effect ◽  
Metal Abundance ◽  
Lyrae Stars

Eleven double-mode (dm) RR Lyrae stars, with periods midway between the periods for the c-type and ab-type RR Lyrae stars, have been identified in the Draco dwarf galaxy by reanalyzing the photometry of Baade and Swope (1961) for 35 stars. The stars are V11, 72, 75, 83, 112, 138, 143, 156, 165, 169 and 190, three of which previously were noted as dm RR Lyraes by Goranskij (1982). The methods of Stellingwerf (1978) and Stobie (1970) were used to find the periods. The period ratios, periods and amplitudes suggest that the stars radially pulsate simultaneously in the fundamental and first overtone modes. The beat masses, estimated from the P1/P0 vs. P0 diagram (Petersen 1973), using as calibration the King Ia (Y=0.299, Z=0.001) models of Cox, Hodson and Clancy (1983, hereafter CHC), are Mbeat/Mo=0.65 for nine stars, = 0.60 for V75 and = 0.55 for V165. If the mass loss rate prior to arriving on the horizontal branch is proportional to the metal abundance (Stobie 1971, CHC), V75 and V165 should be more metal rich than the other nine dm RR Lyraes. In the period-amplitude (P-A) diagram, at a given amplitude, V165 has a smaller period shift relative to the standard M3 line than do the higher mass stars. Subsequently, the correlations of Preston (1959) and Sandage (1982) suggest that it is more metal-rich than the other nine dm RR Lyrae stars in Draco. Furthermore, reanalysis of the P-A and period-mean magnitude relations of all the RR Lyrae stars in Draco shows evidence for a widespread range in the metal abundances. Stars with large period shifts relative to the M3 relation are found to be more luminous than stars with smaller period shifts. The frequency of variable amplitude (ie. Blazhko effect) RR Lyrae stars is greatest for the ab-type stars with short periods. The brightnesses of the highest maxima appear to fit the P-A relation, and the amplitudes of the lowest maxima are variable, with V123 being an extreme example. Figure 3 of Szeidl (1975) shows the analogous situation for M3 RR Lyrae stars with the Blazhko effect. These findings suggest that the amplitude variability is related to the mode-switching activity of the dm RR Lyrae stars.

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

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.

scholarly journals General Properties of the Two Groups of Globular Clusters and Their Variable Stars

1975 ◽  
Vol 67 ◽  
pp. 541-543
Author(s):  
A. V. Mironov ◽  
N. N. Samus'
Keyword(s):  
Chemical Composition ◽  
Globular Clusters ◽  
Variable Stars ◽  
Rr Lyrae Stars ◽  
General Properties ◽  
Rr Lyrae ◽  
Lyrae Stars

The dependences of the numbers of variable stars in globular clusters on the chemical composition are studied. For given metallicity the numbers of RR Lyrae stars reduced to some definite total number of stars in the cluster are different for the two groups of globular clusters introduced by Mironov.

scholarly journals RR Lyrae stars seen from space

2012 ◽  
Vol 333 (10) ◽  
pp. 1044-1047 ◽  
Author(s):  
E. Guggenberger
Keyword(s):  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
Lyrae Stars

scholarly journals The Carnegie RR Lyrae Program: mid-infrared period–luminosity relations of RR Lyrae stars in Reticulum

2018 ◽  
Vol 480 (3) ◽  
pp. 4138-4153 ◽  
Author(s):  
Tatiana Muraveva ◽  
Alessia Garofalo ◽  
Victoria Scowcroft ◽  
Gisella Clementini ◽  
Wendy L Freedman ◽  
...  
Keyword(s):  
Rr Lyrae Stars ◽  
Mid Infrared ◽  
Rr Lyrae ◽  
Lyrae Stars

scholarly journals The MACHO Project Large Magellanic Cloud Variable Star Inventory. XI. Frequency Analysis of the Fundamental‐Mode RR Lyrae Stars

2003 ◽  
Vol 598 (1) ◽  
pp. 597-609 ◽  
Author(s):  
C. Alcock ◽  
D. R. Alves ◽  
A. Becker ◽  
D. Bennett ◽  
K. H. Cook ◽  
...  
Keyword(s):  
Frequency Analysis ◽  
Fundamental Mode ◽  
Variable Star ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
Lyrae Stars

scholarly journals Revisiting CoRoT RR Lyrae stars: detection of period doubling and temporal variation of additional frequencies

2014 ◽  
Vol 570 ◽  
pp. A100 ◽  
Author(s):  
R. Szabó ◽  
J. M. Benkő ◽  
M. Paparó ◽  
E. Chapellier ◽  
E. Poretti ◽  
...  
Keyword(s):  
Temporal Variation ◽  
Period Doubling ◽  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
Lyrae Stars
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