Investigating the orbital structure of the distant Kuiper Belt: Evidence for an undiscovered planet?

Do the orbits of trans-Neptunian objects (TNOs) in the distant Kuiper Belt (>50 au) indicate the existence of a new planet in the solar system? Three important properties in the distant Kuiper Belt remain to be explained consistently: 1) A large population of TNOs with orbits too distant from Neptune’s gravitational influence (i.e., with perihelia q > 40 au; 2) TNOs with very high orbital inclinations (i > 45 deg); 3) The existence of extreme TNOs whose peculiar orbits are difficult to obtain in past Kuiper Belt formation models (e.g., Sedna). Here, we performed N-body computer simulations of the outer solar system including an undiscovered planet to investigate its effects on the orbital structure beyond Neptune. Any resident planet is likely to have more than 0.5 (1) Earth masses and to be located beyond ~150 (200) au in order to explain properties 1 and 3, while more massive and slightly more distant planets are needed to explain property 2. We also confirmed that such planets can preserve resonant populations in the entire distant Kuiper Belt. I will also present observationally testable predictions for new populations of TNOs that would exist due to the gravitational perturbations by this putative planet. Overall, these results will guide future astronomical surveys in search of undiscovered planets located beyond Neptune.