An extended Benford analysis of exoplanet orbital periods

Shukla, Pandey and Pathak (2017) report about their findings of a Benford analysis applied to the physical properties of exoplanets. The present paper gives a short literature overview of previous research on exoplanets. We describe the methods to perform an extended Benford analysis, which considers, both the first digit, and also other digits and digit combinations. Methods for testing conformity with the Benford distribution are discussed and applied to the digits of orbital data of exoplanets.

A first result of this research is that the used data pass most of the tests. It is observed that for most tests on the orbital period values, the almost 4,000 presently known and confirmed exoplanets seem to be sufficient. The analysis of the first, second and third digits (and combinations of these digits) shows a good agreement with the Benford distribution. The analysis of the last two digits indicates that the last significant zero gets lost easily during the export from the exoplanet database. The summation analysis isolates exoplanets with extremely long orbital periods.