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Old February 16th 19, 08:13 PM posted to sci.astro.amateur
corvastro
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Default what (if anything) "defines" an orbit as being "cometary" vs "asteroidal"?

On Saturday, December 22, 2018 at 1:22:36 PM UTC-8, wrote:
Is there some combination of orbital element values that establishes the orbit of a minor solar system body as being "cometary" as opposed to "asteroidal"? Something akin to "eccentricity 0.6, inclination 30d (or retrograde)"? I understand that highly-inclined, highly-eccentric orbits are more likely to be those of a comet than are those orbits with low such values, but are these parameters actually "defined"? (My question is about the orbit itself, not the body - I understand that comets can have "asteroidal orbits" (e.g. 29P) and that asteroids can have "cometary orbits" (e.g. 2006 EX52))


No, orbital elements do not matter, as both comets and asteroids can be perturbed out of their original orbits into greatly different ones. For example: it is possible, in theory, for an asteroid to be flung completely out of the solar system.

The common differentiation is where they formed and their composition. Asteroids formed in the inner solar system and are primarily composed of minerals and rocks. Comets formed far outside the orbit of Pluto and are composed primarily of dust, small rocks and ice.