Observational Evidence of Convective Cycles as the Cause of the Blazhko Effect in RR Lyrae Stars

2010 ◽  
Vol 122 (891) ◽  
pp. 536-540 ◽  
Author(s):  
Richard B. Stothers
Keyword(s):  
Observational Evidence ◽  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
Blazhko Effect ◽  
Lyrae Stars

On the Two Oosterhoff Groups of Globular Clusters

1973 ◽  
Vol 21 ◽  
pp. 196-196
Author(s):  
T. S. Van Albada ◽  
Norman Baker
Keyword(s):  
Stellar Evolution ◽  
Globular Clusters ◽  
Transition Point ◽  
Transition Period ◽  
Observational Evidence ◽  
Horizontal Branch ◽  
Average Difference ◽  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
Lyrae Stars

AbstractThe observational evidence leading to the classification, following Oosterhoff, of globular clusters containing RR Lyrae stars into two distinct groups, is summarized and discussed in the light of results of stellar evolution theory and pulsation theory. The dichotomy is caused, at least in part, by a dichotomy in the ‘transition period’ between the type-ab and type-c stars which reflects a difference in effective temperature at the transition point. When this difference is accounted for, there remains a smaller average difference between the groups, though no longer a clear dichotomy, that is probably a mass and luminosity effect. If this remaining difference is interpreted as a luminosity effect the average difference in luminosity between the two Oosterhoff groups is at most 0.1 mag. It is suggested that Christy’s theoretical relationship between transition period and luminosity cannot be valid, at least not for clusters of different Oosterhoff groups. It is conjectured that the transition-temperature dichotomy may be a reflection of different predominant directions of evolution along the horizontal branch, accompanied by a hysteresis effect in the pulsations.

scholarly journals Oblique Pulsator Model for the Blazhko Effect of RR Lyrae Stars

1995 ◽  
Vol 155 ◽  
pp. 42-43
Author(s):  
Hiromoto Shibahashi ◽  
Masao Takata
Keyword(s):  
Rotation Axis ◽  
Oscillation Mode ◽  
Stellar Rotation ◽  
Rr Lyrae Stars ◽  
Aspect Angle ◽  
Rr Lyrae ◽  
Quadrupole Component ◽  
Blazhko Effect ◽  
Apparent Variation ◽  
Lyrae Stars

AbstractBy assuming that the RR Lyrae stars have fairly strong dipole magnetic fields with the symmetry axis oblique to the rotation axis of the star, we show that the oscillation mode which would be a pure radial oscillation in absence of the magnetic field has a quadrupole component, which is axisymmetric with respect to the magnetic axis. The aspect angle of the quadrupole component changes due to the stellar rotation, and this apparent variation is interpreted as the Blazhko effect in RR Lyrae stars.

scholarly journals Blazhko effect in Cepheids and RR Lyrae stars

2013 ◽  
Vol 9 (S301) ◽  
pp. 241-248
Author(s):  
Róbert Szabó
Keyword(s):  
Time Series Data ◽  
Period Doubling ◽  
High Order ◽  
Series Data ◽  
Theoretical Point ◽  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
Starting Point ◽  
Blazhko Effect ◽  
Lyrae Stars

AbstractThe Blazhko effect is the conspicuous amplitude and phase modulation of the pulsation of RR Lyrae stars that was discovered in the early 20th century. The field of study of this mysterious modulation has recently been invigorated thanks to the space photometric missions providing long, uninterrupted, ultra-precise time-series data. In this paper I give a brief overview of the new observational findings related to the Blazhko effect, such as extreme modulations, irregular modulation cycles and additional periodicities. I argue that these findings together with dedicated ground-based efforts provide us now with a fairly complete picture and a good starting point to theoretical investigations. Indeed, new, unpredicted dynamical phenomena have been discovered in Blazhko RR Lyrae stars, such as period doubling, high-order resonances, three-mode pulsation and low-dimensional chaos. These led to the proposal of a new explanation to this century-old enigma, namely a high-order resonance between radial modes. Along these lines I present the latest efforts and advances from the theoretical point of view. Lastly, amplitude variations in Cepheids are discussed.

FIRST DETECTION OF MULTI-SHOCKS IN RR LYRAE STARS FROM ANTARCTICA: A POSSIBLE EXPLANATION OF THE BLAZHKO EFFECT

2014 ◽  
Vol 148 (5) ◽  
pp. 88 ◽  
Author(s):  
M. Chadid ◽  
J. Vernin ◽  
G. Preston ◽  
C. Zalian ◽  
C. Pouzenc ◽  
...  
Keyword(s):  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
Blazhko Effect ◽  
Lyrae Stars

A New Look at the Blazhko Effect in RR Lyrae Stars with High-Quality Data from the MACHO Project

2000 ◽  
Vol 176 ◽  
pp. 291-298 ◽  
Author(s):  
D. W. Kurtz ◽  
C. Alcock ◽  
R. A. Allsman ◽  
D. Alves ◽  
T. S. Axelrod ◽  
...  
Keyword(s):  
Phase Modulation ◽  
Period Change ◽  
Quality Data ◽  
High Quality Data ◽  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
Blazhko Effect ◽  
First Results ◽  
Lyrae Stars ◽  
Better Than

AbstractWe present the first results of the analysis of 22 Blazhko stars. We find: 1) Blazhko RRab stars that are nearly pure amplitude modulators; 2) Blazhko RRab stars that have both amplitude and phase modulation; 3) A Blazhko RRab star that has an abrupt period change; 4) Proof of the Blazhko effect in RRc stars. Our data show the character of the amplitude and phase modulations of the light curves over the Blazhko cycles far better than has been previously possible.

scholarly journals Does Kepler unveil the mystery of the Blazhko effect? First detection of period doubling in Kepler Blazhko RR Lyrae stars

2010 ◽  
Vol 409 (3) ◽  
pp. 1244-1252 ◽  
Author(s):  
R. Szabó ◽  
Z. Kolláth ◽  
L. Molnár ◽  
K. Kolenberg ◽  
D. W. Kurtz ◽  
...  
Keyword(s):  
Period Doubling ◽  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
Blazhko Effect ◽  
Lyrae Stars

scholarly journals ON THE BLAZHKO EFFECT IN RR LYRAE STARS

2011 ◽  
Vol 731 (1) ◽  
pp. 24 ◽  
Author(s):  
J. Robert Buchler ◽  
Zoltán Kolláth
Keyword(s):  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
Blazhko Effect ◽  
Lyrae Stars

A New Explanation of the Blazhko Effect in RR Lyrae Stars

2006 ◽  
Vol 652 (1) ◽  
pp. 643-649 ◽  
Author(s):  
Richard B. Stothers
Keyword(s):  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
Blazhko Effect ◽  
Lyrae Stars
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