After some thought, I think I'm using the following definition of planet:
An object formed in a protoplanetary disk (http://en.wikipedia.org/wiki/Protoplanetary_disk) (this excludes Oort cloud objects such as Sedna and the interstellar objects Oph 1622), not a star (as a rule of thumb, this means smaller than 14 jupiters), large enough to have had an atmosphere during formation (as a rule of thumb, this means larger than the moon), and not in the gravitational influence of another planet (I mean this to exclude not just moons but also plutinos (http://en.wikipedia.org/wiki/Plutino), though in our particular solar system plutinos are all excluded by the size restriction anyway).
Under this definition, 2003 UB13 almost qualifies, but not quite. Oph 1622 does not, because it doesn't appear to have formed in a proplyd.
There are plenty of other definitions out there, and many of those are at least more concise; the purpose of this poll was to present a bunch of corner cases and see how people's perceptions of the objects affect the validity of the various definitions out there.
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momijizukamori
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Date: 2006-08-17 07:05 pm (UTC)Under this definition, 2003 UB13 almost qualifies, but not quite. Oph 1622 does not, because it doesn't appear to have formed in a proplyd.
There are plenty of other definitions out there, and many of those are at least more concise; the purpose of this poll was to present a bunch of corner cases and see how people's perceptions of the objects affect the validity of the various definitions out there.