A paired test finds no clear 320-day reduction difference in 232 HD 40307 HARPS nights

We test DRS minus SERVAL velocities from 448 public HARPS exposures on 232 nights before the 2015 fibre change. A common ideal orbital shift cancels in this difference. Four linear models give fitted 320-day difference amplitudes of 0.169 to 0.218 m/s. Conditional fixed-period tail fractions range from 0.078 to 0.374. A search from 250 to 400 days gives fractions from 0.055 to 0.243. No test passes the stated 1 percent threshold. Activity terms reduce both velocity amplitudes but leave their difference nearly unchanged. Specified 0.5 m/s differential injections give 98.5 to 99.9 percent recovery; 0.2 m/s injections give only 14.0 to 34.1 percent. Thus the null is weak at the measured scale. It does not confirm a planet or identify a physical cause. Shared spectra, possible shared errors, fixed circular waves and approximate block noise tests limit inference. Original code, aggregate evidence, source hashes and external retrieval steps are included. External source records are excluded.

astronomy · HD 40307 · HARPS · paired reductions · 320 days · null result · stellar activity