What is the third requirement, involving orbital dominance, that a body must meet to qualify as a planet under the IAU definition?
Answer
It must have "cleared the neighborhood" around its orbit
The International Astronomical Union (IAU) established three definitive criteria for classifying a celestial body as a planet in our solar system, and the third criterion specifically deals with orbital dominance. This requirement mandates that the body must have 'cleared the neighborhood' around its orbital path, meaning it is the gravitationally dominant object in that zone, having either accreted or ejected smaller objects. The other two criteria involve orbiting the Sun and achieving hydrostatic equilibrium (being nearly round). Meeting this third criterion is crucial for separating planets from smaller bodies that share orbital zones.
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