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Originally Posted by the_shaggy_one
Also, remember that the wikipedia article is the collective opinions of everyone who participated in writing it, not any sort of authority on the nomenclature of the solar system.
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As a TOP1000 Wikipedia contributor who has focused on asteroids I know that.
I don't count comets as minor planets, nor does the MPC. In a sense it is odd since KBOs are minor planets but comets like Halley which is believed to have originated from there, isn't. Although the term "SSSB" is clumsy, it hopefully makes this more clear.
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Originally Posted by the_shaggy_one
As I understand it, asteroid is still a useful descriptor for objects that are part of the asteroid belt and NEAs, as it represents a dynamical grouping of bodies that share similar orbital and physical characteristics. Specific names for different groups exist, such as Atens, TNOs, Jupiter Trojans, Centaurs, etc. so it's probably best to use those descriptors, rather than the catch-all SSSB.
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Then we agree.
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Originally Posted by the_shaggy_one
the term 'SSSB' replaces the outdated and confusing term 'minor planet', but does not affect the names for more specific dynamic groups.
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Not actually. 'Minor planet' is synonymous to 'asteroid' (or if you don't count TNOs as asteroids, then MP = asteroids + TNOs). I think it's highly unlikely that the term 'minor planet' will be removed from use.
Then why the term "dwarf planet" had to be invented (planetoid, although historically synonymous to asteroids, would have been much better)... To be fair, if Resolution 5B had passed, they would have formed a subset of planets. And it is a nod to Pluto and its kin. Not a planet, but a dwarf planet anyway.
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Originally Posted by the_shaggy_one
Thus, the terms SSSB, dwarf planet, and planet tell us something about how massive the object is, from small irregular bodies, to rounded bodies, to bodies large enough to sweep out the debris of planetary formation. The specific names for dynamical groups tell us where the objects are, and in some cases where they came from or what they're made of. Planets can also form dynamic groups, such as the terrestrial planets and gas giants.
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There's nothing dynamical in terrestrial/gas giant classification. It is based purely on physical properties, but happens to split the groups nicely in dynamical sense in our Solar system since the gas giant's didn't migrate as much as in some planetary systems.
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Originally Posted by the_shaggy_one
So Ceres is both a dwarf planet and asteroid, and is sometimes even counted as a terrestrial planet. Pluto is a dwarf planet, TNO, KBO, and plutino. Eris is a dwarf planet, TNO, and SDO. Both Pluto and Eris also belong to a new and unnamed group of eccentric, inclined, long-period ice dwarfs. (Wouldn't that be a fun bit of terminology, the 'EILPIDs'!)
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Ceres is not a terrestrial planet by any means.
The members in the unnamed group are dwarf planets and are located beyond Neptune. Circular, non-inclined orbits are allowed, so "EILPID" would be a misleading term.
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Originally Posted by the_shaggy_one
To me, this new classification system makes a lot of sense, and avoids being extremely arbitrary. There are going to be borderline cases where it's not exactly clear which groups a body belongs to. I see those are merely opportunities to refine the terminology, and don't see why they should doom the definition as a whole.
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I like the three-tier classification system planet/dwarf planet/SSSB. What I don't like is that the term "asteroid/minor dwarf" isn't a true subset of SSSBs. But I understand it would highly impractical to manage dwarf planets separately.