65P/Gunn
DiscovererJames E. Gunn
Discovery sitePalomar Observatory
Discovery date17 October 1970
Mpc nameP/1954 P1, P/1970 U2
Designations
  • 1953 VIII, 1969 II
  • 1976 III, 1989 XI
  • 1970p
Epoch17 October 2024 (JD 2460600.5)
Observation arc71.13 years
Earliest precovery date8 August 1954[1]
Obs7,963
Perihelion1.597 AU
Aphelion4.737 AU
Semimajor3.453 AU
Eccentricity0.3194
Period6.414 years
Inclination3.237°
Asc node136.09°
Arg peri41.568°
Mean103.17°
Tjup2.991
Earth moid1.903 AU
Jupiter moid0.396 AU
Mean radius< 5.4 km (3.4 mi)[2]
M 110.1
Last p16 June 2025
Next p11 February 2033[3]

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.[4]

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.[5] It had a low brightness of magnitude 16 at that time.[6] In 1972, Elizabeth Roemer managed to observe 65P/Gunn close to aphelion.[7]

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.[1] The link was confirmed by Toshiro Nomura and Brian G. Marsden.[8]

During the very favorable apparition of 1996, 65P/Gunn reached magnitude 12.[6]

Orbit

On 4 February 1970, the comet passed 0.015 astronomical units from Ceres.[9]

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 27 ± 9 kg/s.[10] 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.[11]

CCD photometry conducted between 1993 and 1996 reveal a nucleus that is less than 11 km (6.8 mi) in diameter, later revised to 10.8 km (6.7 mi).[12][2] The comet was very active when it was observed, therefore the size estimate likely represent an upper limit.[2][13]

References

  1. ^ J. Dengel & R. Weinberger (1980-11-17). "Comet on Palomar Sky Survey". IAU Circular. 3540 (2). D. W. Green (ed.)
  2. ^ J. Licandro; G. Tancredi; M. Lindgren; H. Rickman; R. G. Hutton (2000). "CCD Photometry of Cometary Nuclei, I: Observations from 1990–1995". Icarus. 147 (1): 161–179. Bibcode:2000Icar..147..161L. doi:10.1006/icar.2000.6442
  3. ^ "Horizons Batch for 65P/Gunn (90000688) on 2033-Feb-11" (Perihelion occurs when rdot flips from negative to positive). JPL Horizons. Archived 2025-09-29 at the Wayback Machine. Retrieved 2025-09-29. (JPL#K252/43, Soln.date: 2025-Sep-16)
  4. ^ "WISE Catches Comet 65P/Gunn". jpl.nasa.gov. Jet Propulsion Laboratory. 2010-06-14. Retrieved 2014-11-26.
  5. ^ J. E. Gunn & M. Schmidt (1970-12-11). "Comet Gunn (1970p)". IAU Circular. 2294 (1). B. G. Marsden (ed.)
  6. ^ G. W. Kronk. "65P/Gunn". Cometography.com. Retrieved 2025-10-10.
  7. ^ B. G. Marsden (1973). "Comets in 1972". Quarterly Journal of the Royal Astronomical Society. 14: 390–391. Bibcode:1973QJRAS..14..389M
  8. ^ T. Nomura (1981-03-31). "Periodic Comet Gunn". IAU Circular. 3588 (1). B. G. Marsden (ed.)
  9. ^ B. Todorovic-Juchniewicz (12–16 June 1989). On the Evolution of Orbit of Comet P/Gunn. Asteroids, Comets, Meteors III. C. I. Lagerkvist; H. Rickman; B. A. Lindblad (eds.). p. 459. Bibcode:1990acm..proc..459T
  10. ^ M. Ishiguro; Y. Sarugaku; M. Ueno; N. Miura et al. (2007). "Dark red debris from three short-period comets: 2P/Encke, 22P/Kopff, and 65P/Gunn". Icarus. 189 (1): 169–183. Bibcode:2007Icar..189..169I. doi:10.1016/j.icarus.2007.01.003
  11. ^ L. Colangeli; E. Bussoletti; C. C. Pestellini; M. Fulle et al. (1998). "ISOCAM Imaging of Comets 65P/Gunn and 46P/Wirtanen". Icarus. 134 (1): 35–46. Bibcode:1998Icar..134...35C. doi:10.1006/icar.1998.5944
  12. ^ "65P/Gunn – JPL Small-Body Database Lookup". ssd.jpl.nasa.gov. Jet Propulsion Laboratory. Retrieved 14 April 2025.
  13. ^ S. Borysenko; A. Baransky; E. Musiichuk (2019). "Photometric observations of ecliptic comet 47P/Ashbrook–Jackson and selected quasi-Hilda and main-belt comets at Kyiv Comet Station (MPC code - 585) in 2017". Icarus. 317: 44–47. arXiv:2005.11143. Bibcode:2019Icar..317...44B. doi:10.1016/j.icarus.2018.07.003