111P/Helin–Roman–Crockett

Encke-type comet other comets of the same name Comet Helin October 2025 111P/Helin–Roman–Crockett IAUC_4701 Eleanor F. Helin Ron Helin Brian P. Roman Randy L. Crockett Palomar Observatory (675) 5 January 1989 P/1989 A2 1988 XIII, 1989bICQ1 jpldata MPC 25 February 2023 (JD 2460000.5) 23.97 yearsobs_arc 2 January 1989 152 3.707 AU 4.595 AU 4.151 AU 0.1402 8.457 years 4.226° 89.827° 1.109° 72.094° 3.023 2.721 AU 0.589 AU 0.6 km miLamy_2004 8.4 17.2 16 June 2021 9 December 2029Horizons2029 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.Tancredi_1990a During these approaches, it actually orbits Jupiter.Tancredi_1990b The last such approach was in 1976,jpldata the next will be in 2071.jpldata 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.Tancredi_1990a Physical characteristics Estimates for the size of its nucleus in 2004 place it roughly about 1.2 km mi in diameter.Lamy_2004 Follow-up studies in 2007 generally agree with this estimate, and depending on the comet's activity involved, the comet is likely somewhere between 0.92 – 2.78 km mi in diameter.Epifani_2007 Notes "obs_arc" Observation arc from the Minor Planet Center database covering dates from 2 January 1989 until 21 December 2012. References E. M. Epifani P. Palumbo M. T. Capria G. Cremonese M. Fulle L. Colangeli 3 The distant activity of Short Period Comets*– I Monthly Notices of the Royal Astronomical Society 2007 381 2 713–722 2007MNRAS.381..713M 10.1111/j.1365-2966.2007.12181.x free E. F. Helin R. Helin B. P. Roman R. L. Crockett B. G. Marsden Comet Helin–Roman–Crockett (1989b) http://www.cbat.eps.harvard.edu/iauc/04700/04701.html IAU Circular 1989-01-05 4701 1 1989IAUC.4701....1H Comet Names and Designations http://www.icq.eps.harvard.edu/names1.html International Comet Quarterly 2025-10-20 111P/Helin–Roman–Crockett – JPL Small-Body Database Lookup https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=111P ssd.jpl.nasa.gov Jet Propulsion Laboratory 2012-07-26 P. L. Lamy I. Toth Y. R. Fernández H. A. Weaver Comets II The Sizes, Shapes, Albedos, and Colors of Cometary Nuclei https://physics.ucf.edu/~yfernandez/papers/comets2chapter/comets2reprint.pdf 2004 223–264 University of Arizona Press 10.2307/j.ctv1v7zdq5.22 2004come.book..223L j.ctv1v7zdq5.22 978-0-8165-2450-1 9 October 2022 20 October 2025 https://ghostarchive.org/archive/20221009/https://physics.ucf.edu/~yfernandez/papers/comets2chapter/comets2reprint.pdf dead 111P/Helin–Roman–Crockett Orbit http://www.minorplanetcenter.net/db_search/show_object?object_id=111P Minor Planet Center 2014-06-17 G. Tancredi M. Lindgren H. Ricjman Temporary satellite capture and orbital evolution of Comet P/Helin–Roman–Crockett Astronomy & Astrophysics 1990 139 1/2 375–380 1990A&A...239..375T 0004-6361 G. Tancredi The capture of P/Helin–Roman–Crockett by Jupiter Comptes-rendus de la table ronde: Nouveaux Développements en Planétologie Dynamique 1990 273–279 1990ndpd.conf..273T fr Horizons Batch for 111P/Helin-Roman-Crockett on 2029-Dec-09 JPL Horizons Perihelion occurs when rdot flips from negative to positive https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%27111P%27&START_TIME=%272029-Dec-01%27&STOP_TIME=%272029-Dec-19%27&STEP_SIZE=%273%20hours%27&QUANTITIES=%2719%27 2021-09-12 (JPL#8/Soln.date: 2013-Jan-28) External links 1000118 111P 111P/Helin–Roman–Crockett 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 1989IAUC.4714....1H Comet Helin-Roman-Crockett (1989b) Helin E. Helin R. Roman B. Crockett R. Seki T. Kobayashi T. Endate K. Watanabe K. Shao C. -Y. Levy D. International Astronomical Union Circular 4714 1 1989 110P/Hartley 112P/Urata–Niijima Category:Periodic comets 0111 0111 111P 111P # 111P 111P *