117P/Helin–Roman–Alu

Jupiter-family comet 132P/Helin–Roman–Alu September 2026 117P/Helin–Roman–Alu 117P 2022-06-04 image ZTF-sso-235-zr-fov-7.0arcmin.png Comet Helin–Roman–Alu 1 imaged from the Zwicky Transient Facility on 4 June 2022 IAUC_4872 Eleanor F. Helin Brian P. Roman Jeff Alu 2 October 1989 P/1989 T2 Helin–Roman–Alu 1nasa-pds 1987 XXXVII, 1989w jpldata MPC 21 November 2025 (JD 2461000.5) 37.44 yearsobs_arc 10 August 1988 6,945 3.089 AU 5.158 AU 4.124 AU 0.25084 8.375 years 8.662° 58.785° 224.92° 144.68° 2.967 2.046 AU 0.257 AU jpldata <16.4 km miEpifani_2008 5.7 11.4 7 July 2022 26 November 2030Horizons2030 117P/Helin–Roman–Alu, also known as Helin–Roman–Alu 1, is a Jupiter-family comet with an 8.38-year orbit around the Sun. It is also classified as a quasi-Hilda comet.Toth_2006 It is the second of three comets co-discovered by Eleanor F. Helin, Brian P. Roman, and Jeff Alu.comet_h-r-a Physical characteristics Preliminary estimates by James V. Scotti in 1994 revealed that the nucleus of Comet Helin–Roman–Alu 1 is roughly 9.0 km mi in diameter.Scotti_1994 Later estimates in 2005 revealed a much larger nucleus at approximately 32.8 km mi, though it is highly likely that the strong activity seen from the comet at the time were contaminating the data obtained.Epifani_2008 See also Comet Helin Notes "comet_h-r-a" The other two comets discovered by the three astronomers were C/1989 T1 (Helin–Roman–Alu) and 132P/Helin–Roman–Alu respectively. "obs_arc" Observation arc from the Minor Planet Center database covering dates from 10 August 1988 until 18 January 2026. References E. M. Epifani P. Palumbo M. T. Capria G. Cremonese M. Fulle L. Colangeli 3 The distant activity of Short Period Comets*– II https://academic.oup.com/mnras/article-pdf/390/1/265/2965237/mnras0390-0265.pdf Monthly Notices of the Royal Astronomical Society 2008 390 1 265–280 2008MNRAS.390..265M 10.1111/j.1365-2966.2008.13718.x free Horizons Batch for 117P/Helin-Roman-Alu 1 (90001003) on 2030-Nov-26 JPL Horizons Perihelion occurs when rdot flips from negative to positive https://ssd.jpl.nasa.gov/api/horizons.api?format=text&COMMAND=%27DES%3D117P%3BCAP%27&START_TIME=%272030-Nov-26%27&STOP_TIME=%272030-Nov-28%27&STEP_SIZE=%273%20hours%27&QUANTITIES=%2719%27 2023-07-06 (JPL#K222/63 Soln.date: 2023-Jul-06) E. F. Helin B. P. Roman J. Alu etal D. W. Green Comet Helin–Roman–Alu (1989w) http://www.cbat.eps.harvard.edu/iauc/04800/04872.html IAU Circular 1989-10-06 4872 1 1989IAUC.4872....1H 117P/Helin–Roman–Alu – JPL Small-Body Database Lookup https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=117P ssd.jpl.nasa.gov Jet Propulsion Laboratory 2026-09-20 117P/Helin–Roman–Alu Orbit http://www.minorplanetcenter.net/db_search/show_object?object_id=117P Minor Planet Center 2014-06-17 Periodic Comet Names and Designations https://pds-smallbodies.astro.umd.edu/data_sb/resources/periodic_comets.shtml Planetary Data System: Small Body Node NASA 2026-09-20 J. V. Scotti Comet Nuclear Magnitudes https://articles.adsabs.harvard.edu//full/1994BAAS...26.1309./0001375.000.html Bulletin of the American Astronomical Society 1994 26 1375 1994AAS...185.4306S I. Toth The quasi-Hilda subgroup of ecliptic comets – an update https://www.aanda.org/articles/aa/pdf/2006/12/aa3492-05.pdf Astronomy and Astrophysics 2006 448 3 1191–1196 2006A&A...448.1191T 10.1051/0004-6361:20053492 free External links 1000121 117P 117P/Helin–Roman–Alu at the Minor Planet Center database 117P/Helin–Roman–Alu at Gary W. Kronk's Cometography 117P/Helin–Roman–Alu at Roger Groom's website 117P/Helin–Roman–Alu at Seiichi Yoshida's website 116P/Wild 118P/Shoemaker–Levy Category:Periodic comets 117P 0117 117P 117P 117P 117P *