Prospects for unseen planets beyond Neptune

Renu Malhotra
Lunar & Planetary Lab, University of Arizona

Several recent studies have appealed to statistical analyses of the orbital distribution of distant Kuiper belt objects to argue for the existence of a roughly Earth-mass planet orbiting at about three times Neptune’s distance and a roughly ten Earth-mass planet orbiting at about twenty times Neptune’s distance.  These hypothetical planets have been informally labeled Planet 10 and Planet 9.  I will review the arguments and the prospects for the existence of these unseen planets in the distant solar system.