Benford’s law: an application to sunspot data

Abstract

Sunspots, the longest recorded indicators of the solar activity, are fundamental to the understanding of the sun and related solar phenomena. Here we explore whether the data on sunspot areas conforms to Benford’s law (BL) - an empirical observation that in large data the numbers having smaller first significant digits (FSDs) appear far more frequently than do the numbers having larger FSDs. We analyze the areas of individual sunspots, of sunspot groups and total area of all the sunspots visible on the surface of sun at any point of time. Furthermore, we also investigate the daily photometric sunspot index (PSI), the umbral and daily plage areas for conformity to BL. The distribution of FSDs of numbers amongst all the data sets are found to be in good agreement with the predictions of BL except the data on daily plage areas which show some deviations from the law. Interpretation of the obtained results is also given.