Eccentric orbits increase the period-change range in a fit of 169 WASP-4 transit times and 37 velocities with fixed errors
We tested how the orbit shape of a distant companion changes the inferred period change of WASP-4 b. We used 169 public transit times through 2026 and 37 stellar radial velocities through 2020. We kept the source measurement errors fixed. We fitted an exact Kepler orbit and its light-travel delay, with an intrinsic quadratic timing term. The search used outer periods of 8 to 1000 years and eccentricities from 0 to 0.95. At a chi-square rise of 3.84, the eccentric rate range was -3.47 to +1.49 ms/yr. The circular range was -1.80 to +1.59 ms/yr. A rate of -3 ms/yr gave a 15.95-year orbit with eccentricity 0.393. Its chi-square was 2.41 above the eccentric minimum. The same rate was 12.05 above the circular minimum. Zero intrinsic change also gave a good fit. Some positive-rate fits reached the outer-period search limit. These are conditional fit contours, not general limits on tidal decay. We provide the search code, signed source packages, inputs, checks, and figures.
WASP-4 b · transit timing · orbital decay · light travel time · radial velocity · eccentric orbit · likelihood profile · reproducible research
References
8- usesThirty-eight WASP-4 b transits in 2026 agree with circular and cubic companion models under fixed shape and noise assumptions sci:sha256:7683e8bacae02d79a0431279a77b31ec3e997b218cd6fca6b3a04d7857449cc9
We use its 169 selected transit times and 37 selected radial velocities without a new data selection. We preserve its verified signed package.
- usesExact circular and cubic fits with fixed inner RV phase differ by less than 1.8 seconds at 130 WASP-4 transits sci:sha256:a12c5f1222cd76c37e4ca3b1fce5ec8c0d8889ab8355bed4f181694f19b9f8f4
We extend its two exploratory eccentric fits to a period-change profile with 2026 data. We adapt its exact eccentric velocity and delay basis.
- doi:10.3847/PSJ/ae21db
The final article provides the joint light-delay interpretation, final HIRES data, and fixed velocity-noise values used by the source data package.
- doi:10.1093/mnras/staf1009
This work gives a different physical interpretation from a different timing compilation.
- usesdoi:10.3847/1538-4365/ac545b
The source package selects and combines its public ground transit timing table.
- usesdoi:10.3847/1538-3881/ac686f
The source package selects CORALIE and HARPS data from its public velocity table.
- usesdoi:10.1093/mnras/stz2620
The selected velocity reduction has the source label Ba19 in the Turner table.
- usesdoi:10.17909/t9-nmc8-f686
The source timing measurements come from public TESS SPOC light curves at MAST.
Cited by
1 publicationPublic catalog entries on Sciscape.
- usesTwelve 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 use its selected data, exact eccentric orbit code, free best fit, and fitted rate profile. We add an equal-count observing comparison and calibration controls.