121P/Shoemaker–Holt

Jupiter-family comet July 2026 128P/Shoemaker–Holt other comets discovered by Carolyn and Eugene Shoemaker Comet Shoemaker 121P/Shoemaker-Holt 121P 2006-08-01 Spitzer image Level-2-PBCD-MIPS-24um.png Infrared image of Comet Shoemaker–Holt from the Spitzer Space Telescope on 1 August 2006 IAUC_4755 Carolyn S. Shoemaker Eugene Merle Shoemaker Henry E. Holt 9 March 1989 P/1989 E2, P/1995 Q3 Shoemaker–Holt 2nasa-pds 1988 XI, 1989j jpldata MPC 21 November 2025 (JD 2461000.5) 37.19 years 4 March 1989 798 3.733 AU 5.448 AU 4.591 AU 0.18669 9.835 years 20.162° 94.104° 12.047° 87.563° 2.858 2.620 AU 0.131 AU jpldata 3.61 km miKnight_2024 ~10 hoursSnodgrass_2008 (V–R) 0.53 0.03Fernández_2013 470 90 kg/m3Paradowski_2022 6.7 12.6 28 June 2023 5 May 2033Horizons2033 121P/Shoemaker–Holt, also known as Shoemaker–Holt 2, is a Jupiter-family comet with an orbital period of about 10 years. The comet was discovered by Carolyn S. Shoemaker, Eugene M. Shoemaker, and Henry E. Holt on 9 March 1989. The comet then had an apparent magnitude of 13, was diffuse and had a tail about 2 arcminutes long.IAUC_4755 It was recovered by James V. Scotti on 29 August 1995 in images obtained as part of the Spacewatch survey.IAUC_6219 The nucleus of the comet is estimated to have a radius of 3.87 km based on infrared imaging by the Spitzer Space Telescope, when the comet displayed dust emission.Fernández_2013 Observations of the comet from the Isaac Newton Telescope indicate an effective radius of 3.61 kilometers. The rotational period was calculated to be 10 hours, but with high uncertainty.Snodgrass_2008 References Y. R. Fernández M. S. P. Kelley P. L. Lamy I. Toth O. Groussin C. M. Lisse M. F. A’Hearn J. M. Bauer H. Campins A. Fitzsimmons J. Licandro S. C. Lowry K. J. Meech J. Pittichová W. T. Reach C. Snodgrass H. A. Weaver 5 Thermal properties, sizes, and size distribution of Jupiter-family cometary nuclei Icarus 2013 226 1 1138–1170 2013Icar..226.1138F 1307.6191 10.1016/j.icarus.2013.07.021 C. S. Shoemaker E. M. Shoemaker H. E. Holt D. W. Green Comet Shoemaker–Holt (1989j) http://www.cbat.eps.harvard.edu/iauc/04700/04755.html IAU Circular 1989-03-10 4755 1 J. V. Scotti D. W. Green B. G. Marsden Comet P/1995 Q3 (Shoemaker-Holt 2) http://www.cbat.eps.harvard.edu/iauc/06200/06219.html IAU Circular 1995-09-01 6219 2 1995IAUC.6219....2S 0081-0304 121P/Shoemaker–Holt 2 – JPL Small-Body Database Lookup https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=121P ssd.jpl.nasa.gov Jet Propulsion Laboratory 2026-07-13 M. M. Knight R. Kokotanekova N. H. Samarasinha K. J. Meech Comets III Physical and Surface Properties of Comet Nuclei from Remote Observations https://books.google.com/books?id=_dGz0AEACAAJ&pg=PA361 University of Arizona Press 2024 361–404 2304.09309 jj.21819446.18 Periodic Comet Names and Designations https://pds-smallbodies.astro.umd.edu/data_sb/resources/periodic_comets.shtml Planetary Data System: Small Body Node NASA 2026-07-14 M. L. Paradowski A New Indirect Method of Determining Density of Cometary Nuclei https://acta.astrouw.edu.pl/Vol72/n2/pdf/pap_72_2_4.pdf Acta Astronomica 2022 72 2 141–159 2022AcA....72..141P 0001-5237 10.32023/0001-5237/72.2.4 free C. Snodgrass S. C. Lowry A. Fitzsimmons Optical observations of 23 distant Jupiter Family Comets, including 36P/Whipple at multiple phase angles Monthly Notices of the Royal Astronomical Society 2008 385 2 737–756 2008MNRAS.385..737S 0712.4204 10.1111/j.1365-2966.2008.12900.x free 121P/Shoemaker–Holt Orbit http://www.minorplanetcenter.net/db_search/show_object?object_id=121P Minor Planet Center 2026-04-16 Horizons Batch for 121P/Shoemaker-Holt 2 (90001019) on 2033-May-05 JPL Horizons Perihelion occurs when rdot flips from negative to positive https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%27DES%3D121P%3BCAP%27&START_TIME=%272033-May-04%27&STOP_TIME=%272033-May-07%27&STEP_SIZE=%273%20hours%27&QUANTITIES=%2719%27 2026-04-16 External links 1000141 121P 121P/Shoemaker–Holt at the Minor Planet Center database 121P/Shoemaker–Holt at Gideon van Buitenen's website 121P/Shoemaker–Holt at Gary W. Kronk's Cometography 121P/Shoemaker–Holt at Shuichi Nakano's website 121P/Shoemaker–Holt at Seiichi Yoshida's website 120P/Mueller 122P/de Vico Category:Periodic comets 0121 0121 121P 121P 121P 121P 121P * *