YORP-factor fit to the light curve data. For each probed value of possible YORP-induced spin-up factor, ν, marked on the horizontal axis, a χ²-plane was constructed on a fragment of the celestial sphere, similar to the 0-YORP plane shown in Fig. 3. Minimum χ² value, corresponding to the best solution from each plane, versus YORP factor are plotted with blue crosses. The horizontal lines mark the increases above the best-fit χ² minimum: + 1% (green) and + 10% (red). A zoomed view is provided in the right panel and shows that there is a wide range of possible solutions including spin-up, spin-down, or no rotation period change.