A fixed second harmonic gives unresolved later error gains in 138 Ross 128 HARPS exposures

We test whether a second harmonic fitted to 167 older Ross 128 HARPS exposures improves a fit to 138 later exposures. At a fixed orbit period of 9.8556 days, later weighted error falls by 1.21 percent in SERVAL and 2.89 percent in DRS. All eight conditional 95 percent resampling ranges include zero. Four group-sign rules in each product do not resolve a change in harmonic coefficients. Added stable 0.3 m/s waves give positive transfer gains in only 40.6 to 50.6 percent of trials. The older published period reverses both observed gain signs. These results show limited support for this simple temporal check of a weak orbit harmonic. They do not establish eccentricity, a new planet, or a change in the orbit. The two reductions share spectra, the split spans instrument changes, and the later span is only 91 days. Code, aggregate evidence, a figure, exact input hashes and external retrieval steps are included. External observation records are excluded.

astronomy · Ross 128 · HARPS · orbital eccentricity · second harmonic · temporal validation · null result