Both components of the HD 109271 system plotted in a (G − K_s) − M_G diagram. The main-sequence is shown with the gray line and the evolutionary track of DA white dwarfs with a mass of 0.6 M_⊙ is shown with the black dashed line. The photometry of the exoplanet host star HD 109271 A is consistent with a main-sequence star, as expected. In contrast, the detected co-moving companion HD 109271 B is clearly located below the main-sequence, but its photometry agrees well with that of DA white dwarfs.