The 13.5-day signal fits updated HD 1461 velocities better than its yearly aliases in the tested noise models

We test whether updated public HD 1461 radial velocities select the known 13.5-day signal over its yearly aliases. We fit circular signals for b and c to 545 HARPS and HIRES instrument-nights. We use separate seasonal offsets and explicit fixed noise models. The primary c period is 13.501921 days and its amplitude is 1.529 +/- 0.179 m/s. The closest yearly alias increases chi-square by 45.39. The smallest gap is 27.00 in eight models that test white noise, exponential correlated noise, activity terms, and the HARPS velocity extraction. A fit to 472 early nights predicts 73 later nights. The frozen c prediction decreases later chi-square by 9.80. The later cadence has only 21.4% detection power for the early signal at a fixed-period null tail probability of 0.0027 under the primary noise model. This is a check of the established planet HD 1461 c. It is not a new planet discovery or a model-independent rejection of stellar activity. The package includes numeric source extracts, source hashes, two metadata checks, code, results, figures, and offline reproduction instructions.

HD 1461 · radial velocity · exoplanets · yearly aliases · HARPS · HIRES · chronological prediction · detection power · data provenance