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arXiv · 2407.16868

Variable Star Light Curves in Koopman Space

Nicolas Mekhaël·Mario Pasquato·Gaia Carenini·Vittorio F. Braga·Piero Trevisan·Giuseppe Bono·Yashar Hezaveh
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Abstract

We present the first application of data-driven techniques for dynamical system analysis based on Koopman theory to variable stars. We focus on light curves of RRLyrae type variables, in the Galactic globular cluster $\omega$ Centauri. Light curves are thus summarized by a handful of complex eigenvalues, corresponding to oscillatory or fading dynamical modes. We find that variable stars of the RRc subclass can be summarized in terms of fewer ($\approx 8$) eigenvalues, while RRab need comparatively more ($\approx 12$). This result can be leveraged for classification and reflects the simpler structure of RRc light curves. We then consider variable stars displaying secular variations due to the Tseraskaya-Blazhko effect and find a change in relevant eigenvalues with time, with possible implications for the physical interpretation of the effect.

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Nicolas Mekhaël, Mario Pasquato, Gaia Carenini, Vittorio F. Braga, Piero Trevisan, Giuseppe Bono, Yashar Hezaveh. 2024-07-23. Variable Star Light Curves in Koopman Space. https://arxiv.org/abs/2407.16868

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