Pre-selection of solar analogues with differential rotation signature

Abstract

The light curve of a star allows studying the variation of its brightness over time, being suitable for determining rotation periods, detecting planets, studying binary systems and differential rotation. The light curve analysis can be performed with the autocorrelation function (ACF), a robust mathematical tool in the detection of the stellar rotation period, by finding patterns in the photometric data. In this work, a sample of stars from the CoRoT mission is analyzed. The analysis is carried out with the ACF to carry out a pre-selection of stars that show signs of rotational modulation, a determining characteristic for the study of differential rotation. 17 stars were selected by visual inspection of the curves and by the ACF function. It was found that three stars have an excellent profile of autocorrelation function and rotational modulation, three have a good profile and the remaining eleven have inappropriate profiles for the study of differential rotation. The photometric time series analyzes show that the autocorrelation function method is very suitable as a previous criterion for the selection of candidate stars for the study of differential rotation, when they present exponential decay of the oscillation peaks of the light curve.