100P/Hartley

Jupiter-family comet other comets of the same name Comet Hartley (disambiguation)Comet Hartley May 2025 100P/Hartley IAUC_4077 Malcolm Hartley UK Schmidt Telescope 13 June 1985 P/1985 L1P/1991 E1 Hartley 1nasa-pds 1985 VII, 1991 VII 1985f, 1991j jpldata MPC 13 September 2023 (JD 2460200.5) 37.17 yearsobs_arc 666 2.018 AU 4.844 AU 3.416 AU 0.41183 6.354 years 25.567° 37.687° 181.96° 67.750° 2.851 1.003 AU 0.133 AU jpldata < 1.2 km miLamy_2004 10.0 16.2 10 August 2022 15 December 2028Horizons2028 Comet Hartley 1, also known as 100P/Hartley, is a Jupiter family comet with a 6.35-year orbit around the Sun. It is one of 12 comets discovered by Australian astronomer, Malcolm Hartley. On 29 April 2164, the comet will pass 0.487 AU e6km e6mi unit from Earth.jpldata Observational history Discovery Malcolm Hartley discovered the comet from CCD images taken from the UK Schmidt Telescope in Australia on 13 June 1985.IAUC_4077 At the time, the comet was a 16th-magnitude object within the constellation Virgo,Reported initial position upon discovery was: α 11 48, δ 4 21Kronk Meyer Seargent 2017 149–150 with a prominent tail extending about 1 arcminute towards the southeast. Despite the discovery announcement, Hartley remained the comet's only observer for the next three weeks.Kronk Meyer Seargent 2017 149–150 Follow-up observations An additional observation by Hartley on 10 July 1985 has allowed Brian G. Marsden to compute the elliptical orbit of the comet for the first time, revealing that it was a short-period comet with a 5.66-year orbit around the Sun.IAUC_4084 James B. Gibson obtained the only known Northern hemisphere observations of the comet during its first apparition on 27–29 July 1985.Kronk Meyer Seargent 2017 149–150 It was last detected by Alan C. Gilmore on 14 August 1985.Kronk Meyer Seargent 2017 149–150 The small number of observations during its 1985 apparition has caused uncertainties in revising its orbit that it was almost considered lost.cometography It was successfully recovered by David H. Levy, Carolyn and Eugene Shoemaker on the night of 12 March 1991,Kronk Meyer Seargent 2017 574–575 about 16 degrees from its predicted position.IAUC_5209 Marsden later noted that the comet made a close encounter with Jupiter in February 1988, passing within 0.36 AU e6km unit from the giant planet.IAUC_5209 Notes "obs_arc" Observation arc from the Minor Planet Center database covering dates from 13 June 1985 until 15 August 2022. References G. W. Kronk 100P/Hartley 1 https://cometography.com/pcomets/100p.html Cometography.com 2025-05-22 Horizons Batch for 100P/Hartley 1 on 2028-Dec-15 JPL Horizons Perihelion occurs when rdot flips from negative to positive https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%27100P%27&START_TIME=%272028-Dec-15%27&STOP_TIME=%272028-Dec-17%27&STEP_SIZE=%273%20hours%27&QUANTITIES=%2719%27 2023-04-29 (JPL#38/Soln.date: 20 August 2022) M. Hartley B. G. Marsden Comet Hartley (1985f) http://www.cbat.eps.harvard.edu/iauc/04000/04077.html IAU Circular 1985-06-20 4077 1 1985IAUC.4077....1H M. Hartley B. G. Marsden Periodic Comet Hartley (1985f) http://www.cbat.eps.harvard.edu/iauc/04000/04084.html IAU Circular 1985-07-18 4084 1 1985IAUC.4084....1H C. S. Shoemaker E. M. Shoemaker D. H. Levy B. Dintinjana H. Mikuz R. H. McNaught B. G. Marsden 3 D. W. Green Periodic Comet Hartley (1991j) http://www.cbat.eps.harvard.edu/iauc/05200/05209.html IAU Circular 1991-03-16 5209 1 1991IAUC.5209....1S 100P/Hartley 1 – JPL Small-Body Database Lookup https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=100P ssd.jpl.nasa.gov Jet Propulsion Laboratory 2025-05-22 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 j.ctv1v7zdq5.22 9 October 2022 23 May 2025 https://ghostarchive.org/archive/20221009/https://physics.ucf.edu/~yfernandez/papers/comets2chapter/comets2reprint.pdf dead 100P/Hartley Orbit http://www.minorplanetcenter.net/db_search/show_object?object_id=100P Minor Planet Center 2014-11-01 Periodic Comet Names and Designations https://pds-smallbodies.astro.umd.edu/data_sb/resources/periodic_comets.shtml Planetary Data System: Small Body Node NASA 2026-08-27 Bibliography Kronk Gary W. Meyer Maik Seargent David A. J. 2017 Cometography: A Catalog of Comets 6: 1983–1993 Cambridge University Press 978-0-521-87216-4 External links 1000040 100P 100P/Hartley at the Minor Planet Center database 100P/Hartley at Seiichi Yoshida's website 99P/Kowal 101P/Chernykh Category:Periodic comets 0100 100P Category:Discoveries by Malcolm Hartley 100P 100P *