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Old December 23rd 18, 04:54 AM posted to sci.astro.amateur
palsing[_2_]
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Default what (if anything) "defines" an orbit as being "cometary" vs "asteroidal"?

On Saturday, December 22, 2018 at 7:13:56 PM UTC-8, Quadibloc wrote:

Yes, there is, and I believe cometary orbits are ones with such a high
eccentricity that it's hard to tell that they're not parabolic. I can't find the
definition online, I suspect it's something like an eccentricity 0.9 .


Well, I don't know the answer, but a quick search turned up this NASA page...

https://nssdc.gsfc.nasa.gov/planetar...cometfact.html

.... where there is a list of 20 "selected" comets, and if I counted correctly, 5 have eccentricities greater than 0.9 and 15 have eccentricities less than 0.9... so perhaps your suspicions are incorrect... but then, this is just one reference...

In general, it looks like the comets with long periods are 0.9 and those with much shorter periods are 0.9. Also, in general for the comets on that list, the high eccentricity comets have much higher orbital inclinations.

\Paul A