Comparison between light curves of ASCC 571833 (top panel; RT Aur) and ASCC 571737 (bottom panel; HD 45237), both phase folded with the same period P = 3.72816 days. The red line is the weighted mean; the magnitude axis zero-points are arbitrary. The period and shape of the light curves are similar but the amplitudes are different: 0.82 versus 0.13 magnitude. The variability seen in ASCC 571737 is completely caused by that in ASCC 571833.