2009CoAst.159..125T

Time series analysis is a common task in many scientific fields, and so it is in astronomy, too. Fourier Transform and Wavelet Analysis are usually applied to handle the majority of the cases. Even so, problems arise when the time series signal presents modulation in the frequency under inspection. The Variable Sine Algorithmic Analysis (VSAA) is a new method focused exactly on this type of signals. It is based on a single sine function with variable coefficients and it is powered by the simplex algorithm. In cases of phenomena triggered by a single mechanism - that Fourier Transform and Wavelet Analysis fail to describe practically and efficiently - VSAA provides a straightforward solution. The method has already been applied to orbital period changes and magnetic field variations of binary stars, as well as to the Blazhko effect of the pulsating RR Lyrae stars and to sunspot activity.