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Analysis of the Irregular Pulsations of AC Her

Z. Kollath·J. R. Buchler·T. Serre·J. Mattei
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Abstract

The AAVSO lightcurve data of the irregularly pulsating star AC Herculis of the RV Tau class are analysed. The lightcurve is shown to be incompatible with a periodic, or even multiperiodic pulsation, even if allowance is made for evolution. Instead the best explanation is that the irregularly alternating cycles are a manifestation of low dimensional chaos. The lightcurve is found to be generated by a 3 or 4 dimensional dynamics -- 3 or 4 first order ODEs. The (Lyapunov) fractal dimension of the underlying dynamic attractor is computed to be d_L ~ 2.2, smaller than the value of d_L ~ 3.1 found for R Sct.

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Z. Kollath, J. R. Buchler, T. Serre, J. Mattei. 1997-07-08. Analysis of the Irregular Pulsations of AC Her. https://arxiv.org/abs/astro-ph/9707099

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