Evolution of Typhon’s aspect angle (left) and light-curve amplitude (right). Aspect angle is defined as the angle between the Earth–Typhon vector and Typhon’s rotation pole. Light-curve amplitude assumes a triaxial shape model as detailed in Section 4.3. Blue lines and shaded regions show, respectively, the mean and standard deviation of 500 posterior draws. Vertical dotted lines show the times of the first and last of our astrometric observations. Black lines show the case with no precession—referenced to the orbit fitting epoch and using the median shape model—illustrating the evolution of the aspect angle due to Typhon’s heliocentric orbit and Earth’s orbit (the annual variation). Light-curve amplitude measurements and upper limits are from J. Ortiz et al. (2003) and A. Thirouin et al. (2010), the latter of which was used to construct the shape model explaining the good fit at that epoch.