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Paper: Introduction to VSAA – the Method of Variable Sine Algorithmic Analysis and its Applications to Active Binaries
Volume: 435, Binaries – Key to Comprehension of the Universe
Page: 27
Authors: Tsantilas, S.; Livaniou-Rovithis, H.; Latković, O.; Cséki, A.; Djuravšević, G.
Abstract: The quasi-periodic modulation of the orbital period, common among active binaries of RS CVn-type, Algols and contact systems, is mainly attributed to the development of magnetic activity cycles. And in most of the cases the corresponding periodicities are extracted using Fourier transforms. But this leads to the loss of information concerning time, as the analysis is made in the frequency domain only. For this purpose, we have introduced the prototype method of Variable Sine Algorithmic Analysis (VSAA). VSAA analyzes the orbital period in the joined time-frequency domain, and thus provides an accurate description of the time variation. This makes the method ideal for tracing variable periodicities, as detected in the mentioned cases, as well as in many others. VSAA is implemented in a computer code for which a graphical user interface has recently been developed. Here we present a complete analysis of the contact binary AB And using VSAA, which acquires variable frequency and amplitude of its orbital period modulation. In addition, the RMS subsurface magnetic field of the active component has been estimated.
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