List of non-periodic comets

Non-periodic comets (or long-period comets) are comets that do not have confirmed observations at more than one perihelion passage, and thus generally have orbital periods of 200 years or more. They include single-apparition comets that pass through the inner Solar System only once. Non-periodic comets are on near-parabolic orbits that will not return to the vicinity of the Sun for hundreds or thousands of years – if ever. (Some use the term non-periodic comet to refer exclusively to comets that will never return to the vicinity of the Sun.) Comets not expected to return to the inner Solar System include C/1980 E1, C/2000 U5, C/2001 Q4 (NEAT), C/2009 R1, C/1956 R1, and C/2007 F1 (LONEOS).