The published HD 40956 b orbit gives a minimum mass of 4.30 Jupiter masses for a 2.00 solar mass star

We test the mass and orbit size reported for HD 40956 b against the inputs in its source paper. The stated period of 578.6 days, velocity amplitude of 68 m/s, eccentricity of 0.24, and stellar mass of 2.00 solar masses give an exact minimum companion mass of 4.302 Jupiter masses and a relative orbit axis of 1.713 AU. The paper gives 2.7 Jupiter masses and 1.4 AU. When every input is within one quoted error, the calculated ranges are 3.998 to 4.607 Jupiter masses and 1.684 to 1.742 AU. Neither range overlaps the quoted output plus or minus one error. These are deterministic bounds, not confidence intervals. The other two planets in the same paper agree with their quoted values. Four local fits to 54 public radial velocities give central minimum masses of 4.21 to 4.37 Jupiter masses at the same stellar mass. They vary instrument offsets and a common extra Gaussian noise term. A NASA archive snapshot from 22 October 2026 retains the original inconsistent values. Goda and Matsuo (2019) already gave a larger mass at a different stellar mass; this is not the first larger mass report. We add bounded source checks, a dated archive check, raw-velocity sensitivity fits, and a reproducible audit tool. The result assumes a Kepler orbit and the stated stellar mass. It does not validate a planet or determine a true mass. The package preserves source data, provenance, code, results, figures, and reproduction instructions.

HD 40956 b · radial velocity · minimum planet mass · stellar mass · Kepler orbit · catalog consistency · reproducible research · interval bounds