Example of calculating metric XC1 for EPIC 201207669 based on the correlation between its folded spectrum and the folded template (model C). (a) The star’s folded spectrum in blue and two copies of the folded template in grey. (b) The full correlation of the functions where shift = 0 corresponds to their relative position as shown in (a). The position of maximum correlation is marked with a black vertical line. The value of the maximum correlation coefficient, the 52nd percentile of the entire function and its standard deviation are marked with solid, dashed and dotted horizontal green lines, respectively. XC1 is then the difference between the maximum correlation coefficient and the 52nd percentile divided by the standard deviation.