Stellar activity may induce Doppler variability at the level of a few m/s which can then be confused by the Doppler signal of an exoplanet orbiting the star . To first order , linear correlations between radial velocity measurements and activity indices have been proposed to account for any such correlation . The likely presence of two super-Earths orbiting Kapteyn ’ s star was reported in Anglada-Escudé et al . ( 3 ) , but this claim was recently challenged by Robertson et al . ( 24 ) arguing evidence of a rotation period ( 143 days ) at three times the orbital period of one of the proposed planets ( Kapteyn ’ s b , P=48.6 days ) , and the existence of strong linear correlations between its Doppler signal and activity data . By re-analyzing the data using global optimization methods and model comparison , we show that such claim is incorrect given that ; 1 ) the choice of a rotation period at 143 days is unjustified , and 2 ) the presence of linear correlations is not supported by the data . We conclude that the radial velocity signals of Kapteyn ’ s star remain more simply explained by the presence of two super-Earth candidates orbiting it . We also advocate for the use of global optimization procedures and objective arguments , instead of claims lacking of a minimal statistical support .