123P/West–Hartley

Periodic comet June 2025 other comets of the same name Comet West (disambiguation) Comet Hartley (disambiguation)Comet Hartley 123P/West–Hartley Image of comet "West-Hartley (1989k)" Eso8905a.jpg Discovery image of Comet West–Hartley taken from ESO on 11 May 1989.eso1 Richard M. WestMalcolm Hartley European Southern Observatory 11 May 1989 P/1989 E3, P/1995 S2 1988 XVI, 1989k jpldata mpc 7 October 2026(JD 2461320.5) 30.39 years 4,399 2.159 AU 5.616 AU 3.887 AU 7.665 years 0.44469 15.281° 45.848° 103.88° 1.945° 2.832 1.197 AU 0.704 AU jpldata Kokotanekova_2017 Kronk_2017 2.18 0.23 km 3.7 hours 520 80 kg/m3Paradowski_2022 8.2 13.8 17.5(2026-04-03)cobs 21 September 2026Yoshida Van_Buitenen 22 May 2034Comet Apparitions Jet Propulsion Laboratory https://cneos.jpl.nasa.gov/doc/comet_app.pdf 25 September 2026 Comet West–Hartley is a periodic comet roughly 4 km in diameter with a 7.67-year orbit around the Sun. The current orbit does not bring it closer than about 1.2 AU e6km unit from Earth.jpldata It came to perihelion on 21 September 2026 and comes to opposition on 1 May 2027.opposition It next reaches perihelion on 22 May 2034. Physical characteristics The first attempts to measure the effective radius of its nucleus in 2000 were not successful due to too much scatter data in light curves obtained to provide reliable estimates.Lamy_2004 Recent attempts to measure the comet's light curves between 2004 and 2015 revealed that the nucleus is about 2.18 km mi in radius, rotating once every 3.7 hours.Kokotanekova_2017 References R. M. West M. Hartley Image of comet "P/West-Hartley (1989k)" https://www.eso.org/public/images/eso8905a/ www.eso.org European Southern Observatory 30 May 1989 6 June 2025 123P/West–Hartley – JPL Small-Body Database Lookup https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?des=123P ssd.jpl.nasa.gov Jet Propulsion Laboratory 21 November 2023 R. Kokotanekova C. Snodgrass P. Lacerda S. F. Green S. C. Lowry Y. R. Fernández C. Tubiana A. Fitzsimmons H. H. Hsieh 5 Rotation of cometary nuclei: new light curves and an update of the ensemble properties of Jupiter-family comets https://academic.oup.com/mnras/article-pdf/471/3/2974/19510771/stx1716.pdf Monthly Notices of the Royal Astronomical Society 2017 471 3 2974–3007 2017MNRAS.471.2974K 1707.02133 10.1093/mnras/stx1716 free G. W. Kronk M. Meyer D. A. J. Seargent Cometography: A Catalog of Comets 2017 6: 1983–1993 424–426 Cambridge University Press 978-0-521-87216-4 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 6 June 2025 https://ghostarchive.org/archive/20221009/https://physics.ucf.edu/~yfernandez/papers/comets2chapter/comets2reprint.pdf dead 123P/West–Hartley Orbit http://www.minorplanetcenter.net/db_search/show_object?object_id=123P Minor Planet Center 22 March 2016 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 S. Yoshida 123P/West–Hartley http://www.aerith.net/comet/catalog/0123P/ www.aerith.net 25 March 2025 6 June 2025 G. van Buitenen 123P/West-Hartley https://astro.vanbuitenen.nl/comet/123 astro.vanbuitenen.nl 2026-04-26 COBS Observation list: 123P https://www.cobs.si/obs_list?id=88 Crni Vrh Observatory 2026-04-26 Comet 123P/West-Hartley Lightcurve Opposition for 123P/West-Hartley (90001026) on 2027-May-01 JPL Horizons https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%27DES%3D123P%3BCAP%27&START_TIME=%272027-Apr-30%27&STOP_TIME=%272027-May-02%27&STEP_SIZE=%276%20hours%27&QUANTITIES=%271,9,20,23,29%27 2026-05-06 External links 1000164 123P 123P/West–Hartley at the Minor Planet Center database 123P/West–Hartley at Gary W. Kronk's Cometography 123P/West–Hartley at Gideon van Buitenen's website 123P/West–Hartley at Seiichi Yoshida's website 123P/West–Hartley at the Comet Observations Database (COBS) 123P/West–Hartley on 2026 Apr 06 at apmag 17.6 122P/de Vico 124P/Mrkos Category:Periodic comets 123P 0123 Category:Discoveries by Malcolm Hartley # 0123 0123 0123 * *