THE ALL-SKY GEOS RR Lyr SURVEY WITH THE TAROT TELESCOPES: ANALYSIS OF THE BLAZHKO EFFECT

Journal Article · Wed Aug 15 00:00:00 EDT 2012 · Astronomical Journal (New York, N.Y. Online)

DOI:https://doi.org/10.1088/0004-6256/144/2/39· OSTI ID:22034400

Le Borgne, J -F; Klotz, A; Poretti, E ^[1]; Boeer, M ^[2]; Butterworth, N; Dvorak, S ^[3]; Dumont, M; Hambsch, F -J; Vandenbroere, J ^[4]; Hund, F ^[5]; Kugel, F ^[6]; Vilalta, J M ^[7]

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1. Universite de Toulouse, UPS-OMP, IRAP, 31400 Toulouse (France)
2. ARTEMIS, Universite Nice Sophia-Antipolis, CNRS, Observatoire de la Cote d'Azur, Nice (France)
3. American Association of Variable Star Observers (AAVSO), 49 Bay State Rd., Cambridge, MA 02138 (United States)
4. Groupe Europeen d'Observations Stellaires (GEOS), 23 Parc de Levesville, 28300 Bailleau l'Eveque (France)
5. Bundesdeutsche Arbeitsgemeinschaft fuer Veraenderliche Sterne e.V. (BAV), Munsterdamm 90, 12169 Berlin (Germany)
6. Observatoire Chante-Perdrix, 04150 Banon (France)
7. Agrupacio Astronomica de Sabadell (AAS), Apartat de Correus, 50, 08200 Sabadell, Barcelona (Spain)

We used the GEOS database to study the Blazhko effect of galactic RRab stars. The database is continuously enriched by maxima supplied by amateur astronomers and by a dedicated survey by means of the two TAROT robotic telescopes. The same value of the Blazhko period is observed at different values of the pulsation periods and different values of the Blazhko periods are observed at the same value of the pulsation period. There are clues suggesting that the Blazhko effect is changing from one cycle to the next. The secular changes in the pulsation and Blazhko periods of Z CVn are anticorrelated. The diagrams of magnitudes against phases of the maxima clearly show that the light curves of Blazhko variables can be explained as modulated signals, both in amplitude and in frequency. The closed curves describing the Blazhko cycles in such diagrams have different shapes, reflecting the phase shifts between the epochs of the brightest maximum and the maximum O - C. Our sample shows that both clockwise and counterclockwise directions are possible for similar shapes. The improved observational knowledge of the Blazhko effect, in addition to some peculiarities of the light curves, has yet to be explained by a satisfactory physical mechanism.

• OSTI ID: 22034400
• Journal Information: Astronomical Journal (New York, N.Y. Online), Vol. 144, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
AMPLITUDES
ASTRONOMY
ASTROPHYSICS
DIAGRAMS
LIBRARIES
PHASE SHIFT
PULSATIONS
SHAPE
SIGNALS
STAR EVOLUTION
TELESCOPES
VARIABLE STARS
VISIBLE RADIATION