planemo

noun1

1. •
   an astronomical object with enough mass to achieve hydrostatic equilibrium, but not enough to initiate core fusion at any time in its existence. That is, it is rounded in shape and is smaller than a star. Planemos include planets, dwarf planets, and the larger moons of the Solar System (satellite planets), but also sub-brown dwarfs and rogue planets between the stars.

   • Other groups have also recently identified young, isolated planemos; understanding how such isolated, ultra-low masses form presents a challenge. — 2003