Planets are celestial bodies composed of rock or gas that orbit around stars.

There are 3 requirements in deciding if a celestial object is a planet.

  1. Planet must be able to sutainably orbit around a star.
  2. Planet must have the sufficient mass to be a spherical shape.
  3. Planet must be able to "clear out it's neighborhood."

If a celestial object does not pass all three of those requirements they may be otherwise classified as a dwarf planet or asteroid.