This also allowed Anglada-Escude to place the innermost planet in the Habitable or “Goldilocks Zone”, the region around the star where temperatures might be just right for liquid water to exist on the planet’s surface.

But planets are not the only thing that can influence a star’s spectra – Robertson’s reanalysis of the spectra found tracers for starspot activity which varied on a 143 day period. This caused an artefact signal at 143/3 days, or 48 days: precisely the supposed orbital period of Kapetyn b.
This latest result is the third skirmish in a bitter war between the two teams with three habitable-zone planets detected by Anglada-Escude all now refuted by Robertson.
(paper: Stellar activity mimics a Habitable-Zone planet around Kapteyn’s Star )