Abstract
Binary stellar systems, particularly those composed of white dwarfs and brown dwarfs, are crucial for studying the processes that guide star and planet formation. These unique pairs represent the final stage after billions of years of evolution, providing valuable snapshots of stellar lifecycles. By studying these rare systems, we can better understand orbital dynamics, interactions between stars and their companions, and even gain insight into the atmospheres and properties of brown dwarfs, which are typically difficult to observe directly. We built an end-to-end Python pipeline to search Transiting Exoplanet Survey Satellite (TESS) photometry for short-period white dwarf–brown dwarf (WD–BD) binaries. Starting from the Gaia EDR3 White Dwarf catalog, we filtered to bright candidates (G ≤ 16) and programmatically retrieved light curves with Lightkurve. After cleaning (NaN removal, median normalization, and 5-σ clipping), we searched for periodicity with a Lomb–Scargle (LS) periodogram and for box-shaped transits with a Box Least Squares (BLS) periodogram. We processed 4,125 WD candidates, of which 3,752 had usable TESS light curves. Most sources were noise-dominated, but 44 targets show strong, repeatable short-period signals consistent with binarity or transits. Among these, two are known cataclysmic variables (CVs), interacting binaries in which a white dwarf accretes material from a close stellar companion, whose orbital periods and light-curve morphologies match the literature values, validating the pipeline’s sensitivity to short-period variability while illustrating the challenge of distinguishing mass-transferring systems from detached eclipsing binaries. We summarize the pipeline, show representative before/after cleaning and periodogram diagnostics, and present candidates with periods and phase-folded models.
