Summary of ATPM Yarkovsky effect modelling results for (1620) Geographos using its three different shape models (legend) and a fixed maximum equatorial diameter of 5.04 ± 0.07 km. a) Average Yarkovsky semimajor axis drift as a function of thermal inertia at a fixed bulk density of 2000 kg m^-3. b) Average bulk density as a function of thermal inertia derived by comparing the model orbital drift against that measured. c) The distribution of possible bulk densities derived at the 3σ confidence level.