A 51.195-day fit captures at most 31 percent of a pure 58.43-day wave after a quadratic trend in 319 late HD 85512 nights

We test whether the HD 85512 observing cadence can confuse pure sine waves at 58.43 and 51.195 days. After a quadratic trend, exact linear model bounds show that a 51.195-day fit captures at most 30.46 percent of a pure 58.43-day wave in 319 late HARPS nights. All noise-free phase trials select the injected period. Conditional residual sign trials show that recovery of weak waves depends on the noise template. Removal of one known extreme paired night moves the late DRS scan peak from 60.90 to 51.98 days and changes recovery rates. The result rules out exact confusion from the tested cadence alone. It does not reject a planet or prove stellar activity. Shared spectra, fixed weights, selected periods, and unknown noise covariance limit the result. Original code, aggregate evidence, source hashes, a figure, and repeat instructions are included. External measurement records remain outside the bundle.

astronomy · HD 85512 · HARPS · cadence · period aliases · injection recovery · null discovery result