65P/Gunn
Periodic comet
title: "65P/Gunn" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["periodic-comets", "jupiter-family-comets", "numbered-comets", "comets-in-2017", "comets-in-2025", "astronomical-objects-discovered-in-1970"] description: "Periodic comet" topic_path: "general/periodic-comets" source: "https://en.wikipedia.org/wiki/65P/Gunn" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Periodic comet ::
::data[format=table title="Infobox comet"]
| Field | Value |
|---|---|
| name | 65P/Gunn |
| image | Comet 65P Gunn WISE.jpg |
| caption | Infrared image of Gunn's Comet taken from the WISE observatory on 11 June 2010. |
| discovery_ref | |
| discoverer | James E. Gunn |
| discovery_site | Palomar Observatory |
| discovery_date | 17 October 1970 |
| mpc_name | P/1954 P1, P/1970 U2 |
| designations | |
| orbit_ref | |
| epoch | 17 October 2024 (JD 2460600.5) |
| observation_arc | 71.13 years |
| earliest_precovery_date | 8 August 1954 |
| obs | 7,963 |
| perihelion | 1.597 AU |
| aphelion | 4.737 AU |
| semimajor | 3.453 AU |
| eccentricity | 0.3194 |
| period | 6.414 years |
| inclination | 3.237° |
| asc_node | 136.09° |
| arg_peri | 41.568° |
| mean | 103.17° |
| tjup | 2.991 |
| Earth_moid | 1.903 AU |
| Jupiter_moid | 0.396 AU |
| mean_radius | |
| spectral_type | (V–R) |
| M1 | 10.1 |
| last_p | 16 June 2025 |
| next_p | 11 February 2033 |
| :: |
| name = 65P/Gunn
| image = Comet 65P Gunn WISE.jpg
| caption = Infrared image of Gunn's Comet taken from the WISE observatory on 11 June 2010.
| discovery_ref =
| discoverer = James E. Gunn
| discovery_site = Palomar Observatory
| discovery_date = 17 October 1970
| mpc_name = P/1954 P1, P/1970 U2
| designations =
| orbit_ref =
| epoch = 17 October 2024 (JD 2460600.5)
| observation_arc = 71.13 years
| earliest_precovery_date = 8 August 1954
| obs = 7,963
| perihelion = 1.597 AU
| aphelion = 4.737 AU
| semimajor = 3.453 AU
| eccentricity = 0.3194
| period = 6.414 years
| inclination = 3.237°
| asc_node = 136.09°
| arg_peri = 41.568°
| mean = 103.17°
| tjup = 2.991
| Earth_moid = 1.903 AU
| Jupiter_moid = 0.396 AU
| physical_ref =
| mean_radius =
| spectral_type = (V–R)
| M1 = 10.1
| M2 =
| magnitude =
| last_p = 16 June 2025
| next_p = 11 February 2033
65P/Gunn is a periodic comet in the Solar System orbiting the Sun every 6.41 years inside the main asteroid belt between the orbits of the planets Mars and Jupiter.
Observational history
It was discovered on 11 October 1970 by James E. Gunn of Princeton University using the 122-cm Schmidt telescope at the Palomar Observatory. It had a low brightness of magnitude 16 at that time. In 1972, Elizabeth Roemer managed to observe 65P/Gunn close to aphelion.
In 1980, it was noticed that a 19th magnitude comet found in plates obtained by Palomar Observatory on 8 August 1954 was a previous apparition of 65P/Gunn. The link was confirmed by Toshiro Nomura and Brian G. Marsden.
During the very favorable apparition of 1996, 65P/Gunn reached magnitude 12.
Orbit
On 4 February 1970, the comet passed 0.015 AU from Ceres.
Physical characteristics
Infrared observations from the IRAS satellite in 1983 detected a dust trail around 65P/Gunn, indicating that it had a mass loss rate of kg/s. Additional observations from the Infrared Space Observatory in 1996 revealed a strongly asymmetric dust trail, with a higher mass loss rate of 100–300 kg/s by November 1996.
CCD photometry conducted between 1993 and 1996 reveal a nucleus that is less than 11 km in diameter, later revised to 10.8 km. The comet was very active when it was observed, therefore the size estimate likely represent an upper limit.
References
| author1= L. Colangeli | author2= E. Bussoletti | author3= C. C. Pestellini | author4= M. Fulle | author5= V. Mennella | author6= P. Palumbo | author7= A. Rotundi | display-authors= 4 | title= ISOCAM Imaging of Comets 65P/Gunn and 46P/Wirtanen | journal= Icarus | year= 1998 | volume= 134 | issue= 1 | pages= 35–46 | bibcode= 1998Icar..134...35C | doi= 10.1006/icar.1998.5944 }}
| author1= J. E. Gunn | author2= M. Schmidt | editor1= B. G. Marsden | title= Comet Gunn (1970p) | url= http://www.cbat.eps.harvard.edu/iauc/02200/02294.html | journal= IAU Circular | date= 1970-12-11 | volume= 2294 | issue= 1 }}
| author1= J. Dengel | author2= R. Weinberger | editor1= D. W. Green | title= Comet on Palomar Sky Survey | url= http://www.cbat.eps.harvard.edu/iauc/03500/03540.html | journal= IAU Circular | date= 1980-11-17 | volume= 3540 | issue= 2 }}
| author1= T. Nomura | editor1= B. G. Marsden | title= Periodic Comet Gunn | url= http://www.cbat.eps.harvard.edu/iauc/03500/03588.html | journal= IAU Circular | date= 1981-03-31 | volume= 3588 | issue= 1 }}
| author1= M. Ishiguro | author2= Y. Sarugaku | author3= M. Ueno | author4= N. Miura | author5= F. Usui | author6= M. Y. Chun | author7= S. M. Kwon | display-authors= 4 | title= Dark red debris from three short-period comets: 2P/Encke, 22P/Kopff, and 65P/Gunn | journal= Icarus | year= 2007 | volume= 189 | issue= 1 | pages= 169–183 | bibcode= 2007Icar..189..169I | doi= 10.1016/j.icarus.2007.01.003 }}
| title= 65P/Gunn – JPL Small-Body Database Lookup | url= http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=65P | website= ssd.jpl.nasa.gov | publisher= Jet Propulsion Laboratory | access-date= 14 April 2025 }}
| title= WISE Catches Comet 65P/Gunn | url= https://www.jpl.nasa.gov/images/pia13115-wise-catches-comet-65pgunn/ | website= jpl.nasa.gov | publisher= Jet Propulsion Laboratory | date= 2010-06-14 | access-date= 2014-11-26 }}
| author1= G. W. Kronk | title= 65P/Gunn | url= http://cometography.com/pcomets/065p.html | website= Cometography.com | access-date= 2025-10-10 }}
| author1= J. Licandro | author2= G. Tancredi | author3= M. Lindgren | author4= H. Rickman | author5= R. G. Hutton | title= CCD Photometry of Cometary Nuclei, I: Observations from 1990–1995 | journal= Icarus | year= 2000 | volume= 147 | issue= 1 | pages= 161–179 | bibcode= 2000Icar..147..161L | doi= 10.1006/icar.2000.6442 }}
| author1= B. G. Marsden | title= Comets in 1972 | url= http://adsabs.harvard.edu/full/1973QJRAS..14..389M | journal= Quarterly Journal of the Royal Astronomical Society | year= 1973 | volume= 14 | pages= 390–391 | bibcode= 1973QJRAS..14..389M }}
| title= 65P/Gunn Orbit | url= http://www.minorplanetcenter.net/db_search/show_object?object_id=65P | publisher= Minor Planet Center | access-date= 2025-04-14 }}
| author1= B. Todorovic-Juchniewicz | editor1= C. I. Lagerkvist | editor2= H. Rickman | editor3= B. A. Lindblad | title= On the Evolution of Orbit of Comet P/Gunn | conference= Asteroids, Comets, Meteors III | location= Uppsala University | date= 12–16 June 1989 | page= 459 | bibcode= 1990acm..proc..459T }}
|title=Horizons Batch for 65P/Gunn (90000688) on 2033-Feb-11 |publisher=JPL Horizons |type=Perihelion occurs when rdot flips from negative to positive |url=https://ssd.jpl.nasa.gov/api/horizons.api?format=text&COMMAND=%27DES%3D65P%3BCAP%27&START_TIME=%272033-Feb-09%27&STOP_TIME=%272033-Feb-14%27&STEP_SIZE=%273%20hours%27&QUANTITIES=%2719%27 |archive-url=https://web.archive.org/web/20250929200613/https://ssd.jpl.nasa.gov/api/horizons.api?format=text&COMMAND=%27DES%3D65P%3BCAP%27&START_TIME=%272033-Feb-09%27&STOP_TIME=%272033-Feb-14%27&STEP_SIZE=%273%20hours%27&QUANTITIES=%2719%27 |archive-date=2025-09-29 |url-status=live |accessdate=2025-09-29}} (JPL#K252/43, Soln.date: 2025-Sep-16)
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