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J/A+A/390/585       Light curve of R Cygni                         (Kiss+, 2002)

Period-doubling events in the light curve of R Cygni: Evidence for chaotic behaviour. Kiss L.L., Szatmary K. <Astron. Astrophys. 390, 585 (2002)> =2002A&A...390..585K
ADC_Keywords: Stars, variable ; Stars, late-type ; Photometry Keywords: stars: variables: general - stars: late-type - stars: AGB and post-AGB - stars: individual: R Cygni Abstract: A detailed analysis of the century long visual light curve of the long-period Mira star R Cygni is presented and discussed. The data were collected from the publicly available databases of the AFOEV, the BAAVSS and the VSOLJ. The full light curve consists of 26655 individual points obtained between 1901 and 2001. The light curve and its periodicity were analysed with help of the O-C diagram, Fourier analysis and time-frequency analysis. The results demonstrate the limitations of these linear methods. The next step was to investigate the possible presence of low-dimensional chaos in the light curve. For this, a smoothed and noise-filtered signal was created from the averaged data and with the help of time delay embedding, we have tried to reconstruct the attractor of the system. The main result is that R Cygni shows such period-doubling events that can be interpreted as being caused by a repetitive bifurcation of the chaotic attractor between a period 2T orbit and chaos. The switch between these two states occurs in a certain compact region of the phase space, where the light curve is characterized by ∼1500-day long transients. The Lyapunov spectrum was computed for various embedding parameters confirming the chaotic attractor, although the exponents suffer from quite high uncertainty because of the applied approximation. Finally, the light curve is compared with a simple one zone model generated by a third-order differential equation which exhibits well-expressed period-doubling bifurcation. The strong resemblance is another argument for chaotic behaviour. Further studies should address the problem of global flow reconstruction, including the determination of the accurate Lyapunov exponents and dimension. Objects: ---------------------------------------------------------- RA (2000) DE Designation(s) ---------------------------------------------------------- 19 36 49.4 +50 11 59 R Cygni = HD 185456 ---------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file rcygall.dat 15 26655 Visual estimates (AFOEV, BAA, VSOLJ) rcygavg.dat 15 2745 10-day bins signal.dat 15 3668 Smoothed signal
Byte-by-byte Description of file: rcygall.dat rcygavg.dat signal.dat
Bytes Format Units Label Explanations
1- 10 F10.2 d JD Julian Date of observation 12- 15 F4.1 mag mag Visual magnitude
Acknowledgements: Laszlo Kiss ,
(End) Patricia Bauer [CDS] 17-Jul-2002
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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