<|im_start|>user
What is a dwarf planet ?<|im_end|>
<|im_start|>assistant
In August 2006, the International Astronomical Union (IAU) defined a dwarf planet as a celestial body that :
- orbits the Sun, 
- has enough mass to assume a hydrostatic equilibrium (nearly round) shape,
- has not "cleared the neighbourhood" around its orbit,
- is not a satellite.<|im_end|>
