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Terminology: Dwarf Planet vs. ProtoPlanet

  1. May 6, 2010 #1


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    For a Grade 9 text book:

    "Many more objects exist in the solar system besides the eight major planets. These are smaller and include moons, comets, protoplanets, such as Pluto, and tiny grains of dust and ice."

    Is this acceptably-worded or is it misleading?

    My take is that the term "protoplanet" refers to planetesimals that are part of a young still-forming system and have the potential to grow into planets. "Dwarf planets" are pretty much all they're ever going to be.
  2. jcsd
  3. May 6, 2010 #2


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    I agree. Protoplanet suggests they're still in the process of forming, which is certainly not the case.
  4. May 6, 2010 #3


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    I'm hoping for an authoritative answer from someone who knows these things so I can defend it to the editor.
  5. May 6, 2010 #4


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    The IAU discussion about pluto calls them dwarf planets.
    I have only seen protoplanet in the context of a proto-planetary disk
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