111P/Helin–Roman–Crockett is an Encke-type comet with an 8.46-year orbit around the Sun. It was co-discovered by Eleanor and Ron Helin, Brian P. Roman and Randy L. Crockett on 5 January 1989 from images obtained about 1-2 days prior.
Orbit Comet Helin–Roman–Crockett is known for making extremely close approaches to Jupiter being a quasi-Hilda comet. During these approaches, it actually orbits Jupiter. The last such approach was in 1976, the next will be in 2071. The Jovian orbits are highly elliptical and subject to intense Solar perturbation at apojove which eventually pulls the comet out of Jovian orbit for the cycle to begin anew.
Simulations predict such a cycle is unstable, the object will either be captured into an encounter orbit (e.g. Shoemaker-Levy 9) or expelled into a new orbit which does not have periodic approaches. This implies that 111P's orbit is recent within the past few thousand years.
Physical characteristics Estimates for the size of its nucleus in 2004 place it roughly about in diameter. Follow-up studies in 2007 generally agree with this estimate, and depending on the comet's activity involved, the comet is likely somewhere between in diameter.
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References
External links
at the Minor Planet Center database 111P/Helin–Roman–Crockett at Seiichi Yoshida's website 111P/Helin–Roman–Crockett at Gary W. Kronk's Cometography