Predicted values of the Yarkovsky effect and density for asteroid (138852) 2000 WN10. Bottom panel: Predicted semimajor axis drift da/dt (ordinate) due to the Yarkovsky effect from our model for three different values of the bulk density (1.5, 2, and 2.5gcm⁻³; see the labels) are shown by the solid curves; the abscissa is the surface thermal inertia in SI units (Jm⁻² s⁻⁰⁵ K^-1). We assumed the rotation state and shape model from the light-curve inversion in Sect. 2.4 and an effective size of 300 m. The grayscale horizontal region shows the value (17.8 ± 2.9) × 10^-4auMy^-1 from the orbit determination. Top panel: Model-predicted bulk density to match the observed value of the semi-major axis drift shown by the grayscale region. The solid line in the middle shows the exact correspondence surrounded by a map of the sigma interval of the Yarkovsky drift. The nominal effective size of 300 m is used. If this value were higher or lower, the density solution would shift in the direction indicated by the arrows (preserving the ρ_b D value). The analysis of ten different shape models of (138852) 2000 WN10 reveals a variation of ±3% about the median value used in the figure. The effects of small-scale surface roughness, if important, would shift the solution toward a lower value by typically 10–30% (see Rozitis & Green 2012).