What is a planet?

  title={What is a planet?},
  author={Steven L. Soter},
  journal={Scientific American},
  volume={296 1},
  • S. Soter
  • Published 16 August 2006
  • Physics, Geology
  • Scientific American
A planet is an end product of disk accretion around a primary star or substar. I quantify this definition by the degree to which a body dominates the other masses that share its orbital zone. Theoretical and observational measures of dynamical dominance reveal gaps of 4-5 orders of magnitude separating the eight planets of our solar system from the populations of asteroids and comets. The proposed definition dispenses with upper and lower mass limits for a planet. It reflects the tendency of… 
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