The four-hour signal toward GJ 251 matches a known binary in six TESS sectors

We identify a specific catalog source for the four-hour brightness signal in the TESS data for GJ 251. Earlier work had placed the signal on nearby pixels in Sector 20. We fit light curves and signal images in Sectors 20, 45, 47, 60, 71, and 72. Gaussian image centers lie 0.025 to 0.097 pixel from Gaia DR3 939072235377460352, also named ASASSN-V J065445.43+331533.1. They lie 1.736 to 2.019 pixels from GJ 251. The source is a known eclipsing binary. Its Gaia period is 0.330852725 day. Twice its frequency agrees with each sector peak within two standard errors under the tested noise model. The fixed-frequency PDCSAP semi-amplitude is 168 to 222 parts per million across the six sectors. Alternate baselines, quality masks, nuisance terms, and image moments support the source match. The result adds a named source and measurements across six sectors to the earlier contamination finding. The image errors exclude response-shape and WCS errors. The study does not establish a new planet, a new variable star, or a bound on a smaller intrinsic signal. The package includes code, original light curves, small pixel inputs, archive hashes, catalog queries, results, figures, and commands to repeat the work.

GJ 251 · TESS · eclipsing binary · source identification · photometric contamination · ASASSN-V J065445.43+331533.1 · Gaia DR3 · reproducible research