Phase offset measurements for the non-convex radar-derived shape model of asteroid (85990) 1999 JV6, with λ = 132 °, β = −86 °, period P = 6.536787 h, and starting point T₀ = 2457425.214 (February 2016). The phase offsets are expressed in degrees with the year of observation on the horizontal axis. The blue squares represent measurements for individual light curves. The phase offsets of the light curves utilised in combination with radar data for shape modelling are marked with black circles. The blue dotted lines indicate the possiblespread in phase offsets due to uncertainty in the measured sidereal period alone, i.e. the uncertainty is 7 × 10⁻⁶ h. The solid red line marks the best-fit YORP solution with ν = (3.1 ± 2.4) × 10⁻⁸ rad day⁻², (with a standard deviation of the quadratic function fit to the data of σ ≈ 1.2°). The black dashed line marks best fit, assuming a constant-period (zero-YORP) solution (the gradient of the line corresponds to an error in the sidereal period of 6 × 10⁻⁶ h with a standard deviation of the line fit to the data of σ ≈ 1.4°).