engleski

Search for long-term brightness variations in light curves

Some types of variable stars often show long-term variations superimposed on the dominant short-period changes in brightness. Removal of the short-term component is crucial if we are interested to study the long-term variations. We propose Phase Distribution Minimisation (PDM) method as a tool for removal of short term periodic brightness variations and for the study of the residual brightness variations. We have shown that this method is robust, precise and efficient in removing short-term variations, as well as in the determination of the periods. This method can analyse and remove any periodic brightness variations regardless of the shape of the light curve, which greatly reduce the computing time, and can detect periods of the order of the observational time interval. The method was successfully applied in the study of irregular long-term variations caused by dust in symbiotic Miras. PDM method was also used to detect Blazhko effect in RR Lyrae and Cepheids as changes in pulsational amplitudes. Our results show that PDM method can be successfully applied to detect and analyse long-term changes in light curves of variety of variable stars, from short-period RR Lyrae to long-period Miras. This means that the method can be used to analyse a large number of different light curves expected to be obtained by LSST survey.

AGB stars, symbiotic binaries, radiative transfer, numerical modelling

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