“…We present the colors of 2010 XC 15 in Figure 4. We estimated the systematic uncertainties of the g − r, r − i, and r − z colors in our observations, δ g−r , δ r−i , and δ r−z , on the basis of the photometric measurements of the reference stars (Beniyama et al 2023): δ g−r = 0.03 and δ r−i = 0.03 in the observations with the g-, r-, and i-band filters on December 23; δ g−r = 0.02 and δ r−z = 0.02 in the observations with the g-, r-, and z-band filters on December 23; δ g−r = 0.02 and δ r−i = 0.02 in the observations with the g-, r-, and i-band filters on December 24; and δ g−r = 0.01 and δ r−z = 0.01 for the observations with the g-, r-, and z-band filters on December 25. The weighted average colors of 2010 XC 15 , except for the first night, when the conditions of the sky were not ideal, were derived as g − r = 0.435 ± 0.008, r − i = 0.158 ± 0.017, and r − z = 0.186 ± 0.009.…”