Radio images of Pollux at 21.2 GHz (left), 9 GHz (middle), and 3 GHz (right). Contours are set to (− 3,3,4,...11) × σ_rms where σ_rms is the rms noise in each image. The red cross marks the expected position of the photosphere at the epoch of each observation. The restoring beam is shown in the bottom left of each image. Note the scales on the axes in each panel double in size from left to right.