We present fBLS -- a novel fast-folding technique to search for transiting planets, based on the fast-folding algorithm (FFA), which is extensively used in pulsar astronomy. For a given lightcurve with N data points, fBLS simultaneously produces all the binned phase-folded lightcurves for an array of Np trial periods. For each folded lightcurve produced by fBLS, the algorithm generates the standard BLS periodogram and statistics. The number of performed arithmetic operations is O(Np⋅logNp), while regular BLS requires O(Np⋅N) operations. fBLS can be used to detect small rocky transiting planets, with periods shorter than one day, a period range for which the computation is extensive. We demonstrate the capabilities of the new algorithm by performing a preliminary fBLS search for planets with ultra-short periods in the Kepler main-sequence lightcurves. In addition, we developed a simplistic signal validation scheme for vetting the planet candidates. This two-stage preliminary search identified all known ultra-short planet candidates and found three new ones.
@article{arxiv.2204.02398,
title = {fBLS -- a fast-folding BLS algorithm},
author = {Sahar Shahaf and Barak Zackay and Tsevi Mazeh and Simchon Faigler and Oryna Ivashtenko},
journal= {arXiv preprint arXiv:2204.02398},
year = {2022}
}