Predicted heliocentric apparent R magnitude variation with the orbital phase of the putative P9. The highest brightness is at perihelion (zero orbital phase), and the lowest brightness is at aphelion (0.5 orbital phase). Owing to the very large heliocentric distance of P9, the difference between the opposition geocentric and heliocentric magnitudes is very small: ~0.002 mag. Scaling of the orbital scale: phase = 1 corresponds to one complete orbit around the Sun, which is 18 520 years for a semimajor axis of 700 au.