Вроде бы Харон оставили "просто спутником"...
Похоже, они сами не разобрались в дефенициях. По крайней мере, они далеки от юридической точности. Три категории:
(1) A "planet" is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.
(2) A "dwarf planet" is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.
(3) All other objects except satellites orbiting the Sun shall be referred to collectively as "Small Solar-System Bodies".
Сразу можно сказать, что экзопланеты сюда не попадают. То есть, тела у других звезд планетами называть не следует. Кроме того, нет определения понятия "спутник".