# Why Comet C/2020 F3 Neowise returns even it's orbit is near- parabolic?

I have read in Wikipedia about Comet C/2020 F3 Neowise that it's orbit is near-parabolic. But in another section, it says that it is a non-periodic comet whlith orbital period ranging from 4500 years to 6800 years.

My doubt is how a comet returns back if it is in a parabolic orbit and why it is non-periodic?

Here is the Wikipedia link: https://en.m.wikipedia.org/wiki/C/2020_F3_(NEOWISE)

• It is a long-periodic comet. "Non-periodic" means that the comet wouldn't return for ten thousands of years and that we can't determine precisely when it would return. So the Wikipedia section is wrong. Jul 18 '20 at 8:32
• Isn't non-periodic means we can't predict when it comes back? Also the reference in Wikipedia page is NASA JPL website. It says about period of comet. JPL Horizons barycentric solution for epoch 1950 (before entering planetary region) Goto JPL Horizons Ephemeris Type: Orbital Elements Center: @0 (Solar System Barycenter) Time Span: 1950-01-01 to 2050-01-01 and Step Size: 100 years 1950-Jan-01 is "PR = 1.63 × 106/365.25 days" = 4462 years (For long-period comets on multi-thousand year orbits, asymmetric outgassing will affect the highly sensitive orbital period and eccentricity.) Jul 18 '20 at 8:44
• Link to the reference : ssd.jpl.nasa.gov/… Jul 18 '20 at 8:45

Comet naming conventions limit "periodic comets" to those comets whose orbital period is less than 200 years. Comets in elliptical orbits with a period of greater than 200 years are classified as non-periodic. Comets in parabolic or hyperbolic trajectories are also classified as non-periodic (and they will never again approach the primary).

• Thank you for the answer. Can you explain how it comes back even having a parabolic trajectory? Jul 18 '20 at 12:40
• @AthulRT - ??? I didn't write anything like that. That said, eccentricity is computed by assuming things that are know to be not true (two body problem, no outgassing by the comet, no relativistic effects, ...) So even a comet with an apparent eccentricity slightly greater than 1.0 might well return after a long, long time. The only two objects that have been prefixed by I, for interstellar, have statistically significant hyperbolic excess velocities. Jul 18 '20 at 15:30
• I submitted an edit to try to make the similarity / distinction clearer to @AthulRT. Jul 20 '20 at 18:37