Twelve ideal velocities with 5 m/s errors over three seasons reduce local WASP-4 period change errors in 22 orbit cases with one stable offset

We test how twelve new stellar velocities can help separate intrinsic period change from outer companion motion in WASP-4. We use 169 transit times and 37 velocities from a signed public SCI data chain. We compare five ideal observing allocations in 22 fitted eccentric orbit cases. Each new visit has an assumed independent total error of 5 m/s. All orbit parameters, clock terms, and instrument constants remain free in the local information calculation. With one stable constant for the new instrument, four visits in each of 2027, 2029, and 2031 give local rate errors of 0.657–0.880 ms/year. Twelve visits in 2027 give 0.867–1.382 ms/year. The paired decrease is 10.5–44.1 percent across the 22 cases. With a free constant in each season, the three-season range becomes 0.869–1.461 ms/year. Exact refits to fitted means show asymmetric finite rate costs and an alternative orbit at the period search limit. The local errors are conditional design measures, not forecast confidence intervals or detection probabilities. The cases sample one fitted profile and do not cover all allowed orbits. No future transit times are added. The package preserves exact inputs, a signed source chain, code, proposed dates, fit starts, numerical checks, figures, and instructions for a repeat. This work gives an observing design result. It does not measure a new decay rate or establish a new planet.

WASP-4 · orbital decay · radial velocity · transit timing · observing design · light travel time · instrument offsets · Fisher information · reproducible research