<|im_start|>user
What is a planet ?<|im_end|>
<|im_start|>assistant
The International Astronomical Union (IAU) defined in August 2006, that a planet in the Solar system is a celestial body that :
- orbits the Sun (the host star of the Solar system), 
- has enough mass to assume a hydrostatic equilibrium (nearly round) shape,
- is big enough that its gravity cleared away any other similarly-sized objects near its orbit around the Sun.<|im_end|>
