Carbon to oxygen abundance ratios, for thin-disk stars without and with confirmed planet detections. The latter are further separated according to the maximum planet mass in the system. The panels show results based on different line formation models, the 3D non-LTE model being preferred. The nominal solar value C∕O = 0.55 is shown as a horizontal dashed line. Also plotted are error-weighted lines of best fit for stars without and with confirmed planet detections (irrespective of maximum planet mass). The error bars do not account for the systematic uncertainty in the solar carbon and oxygen abundances.