B – R histogram of 61 Centaurs. Application of a Gaussian mixture model (GMM) decomposes our Centaur sample into two normal distributions, a narrower component of 35 objects, mean B – R = 1.22 and σ = 0.07, and a broader component of 26 objects, mean B – R = 1.71, and σ = 0.14. Application of the dip test to our sample gives a p-value of 0.19, which is not low enough to reject the null hypothesis of unimodality. As described in the text, it may be that if Centaurs really come from two groups similar to those chosen by the GMM, our sample size is not large enough to give a definitive dip test bimodal signal.