Separate activity slopes remove up to 53.2 percent of 471-day signal information in 194 Gl 229 HARPS exposures

We test how linear activity fits affect a trial planet signal in 194 matched Gl 229 HARPS exposures. Four shared activity slopes retain 92.64 to 98.12 percent of conditional information in a fixed 471-day sine wave over all phases. Separate slopes for two instrument eras retain 46.78 to 93.98 percent. The smallest retained fraction stays between 45.66 and 47.34 percent across four fixed noise weights. Exact projections, dense injections and joint fits agree. Three public velocity extractions also give different descriptive amplitudes at 122 days. These tests assume measured indicators and diagonal noise. They do not establish a planet, identify a stellar or instrument cause, or reconstruct the published Gaussian-process model. Common spectra do not provide independent confirmation. Code, source hashes, retrieval steps, aggregate results and a figure are preserved. External measurement tables are excluded.

astronomy · Gl 229 · HARPS · activity correction · signal information · radial velocity