22P/Kopff

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22P/Kopff
Comet 22P Kopff.jpg
Comet Kopff photographed from a 14" reflector telescope on 27 June 2009
Discovery
Discovered by August Kopff
Discovery site Königstuhl Observatory
Discovery date23 August 1906
Designations
P/1906 Q1
P/1919 O1
  • 1906 IV, 1919 I
  • 1926 II, 1932 III
  • 1939 II, 1945 V
  • 1951 VII, 1958 I
  • 1964 III, 1970 XI
  • 1977 V, 1983 XIII
  • 1990 I
Orbital characteristics [1]
Epoch 31 March 2024 (JD 2460400.5)
Observation arc 117.6 years
Number of
observations		5,043
Aphelion 5.32 AU
Perihelion 1.54 AU (epoch 2024)
1.32 AU (real-world) [2] [a]
Semi-major axis 3.43 AU
Eccentricity 0.551
Orbital period 6.357 years
Inclination 4.753°
120.58°
Argument of
periapsis 		162.92°
Mean anomaly 115.26°
Last perihelion18 March 2022
Next perihelion28 June 2028 [2]
TJupiter 2.866
Earth MOID 0.539 AU
Jupiter MOID 0.08 AU [3]
Physical characteristics
Mean radius
1.7±0.2 km [4]
12.3±0.8 hours [5]
0.042±0.01 [4]
Comet total
magnitude (M1)		11.9

Comet Kopff or 22P/Kopff is a Jupiter-family comet with a 6.36-year orbit around the Sun. Discovered on 23 August 1906, it was named after its discoverer, August Kopff. The comet was missed on its November 1912 return, but was recovered on June 1919 and has been seen at every apparition since. [6] Close approaches to Jupiter in 1938 and 1943 [3] decreased the perihelion distance and orbital period. [7] [8] 22P/Kopff’s last perihelion passage was 18 March 2022. [1]

Contents

It will pass 0.439 AU (65.7 million km) from Jupiter on 25 April 2026, [3] then come to perihelion on 28 June 2028 at 1.32 AU from the Sun, [2] and then pass 0.353 AU (52.8 million km) from Earth on 13 July 2028. [3]

Observations

Perihelion distance
at different epochs [7]
Epoch Perihelion
(AU)
18443.04
18512.02 [b]
19061.70
19451.50
19581.52
19901.59
20281.32 [2]
20401.19

22P/Kopff was discovered at Königstuhl Observatory on Heidelberg, Germany. [8] Kopff analyzed photographic plates which he exposed on August 20, 1903, against pre-discovery images of the same region. On August 23, 1903, Kopff concluded it to be a comet with an estimated apparent magnitude of 11. On mid-September 1906, the short-period nature of the comet was recognized by a team headed by Kiel Ebell of the Berkeley Astronomical Department. The comet was missed when it made a return on November 25, 1912, however on June 25, 1919, astronomers recovered the comet. The comet was located less than three days from the predicted position. Over the next several returns to Earth, none were notable until the 1945 comet’s return when the comet peaked at magnitude 8.5. The increase in brightness was a result of Jupiter altering the comet’s orbit between the years of 1939 to 1945. This change in orbit brought the comet closer to the Sun. The 1951 return was unique due to the comet being 3 magnitudes fainter than what was expected when recovered in April 1951. But the comet still reached magnitude 10.5 in October 1951. A very close pass to Jupiter in 1954 increased the comet’s perihelion distance to 1.52 AU and increased the orbital period to 6.31 years. [8] On November 30, 1994, Carl W. Hergenrother was able to recover the comet at a stellar magnitude of 22.8 using the 1.5-m reflector at the Catalina Sky Survey. [8] The comet reached magnitude 7 during the 1996 perihelion passage. [9]

The comet nucleus is estimated to be 3 km (2 mi) in diameter with an albedo of 0.05. [3] The nucleus is dark because hydrocarbons on the surface have been converted to a dark, tarry like substance by solar ultraviolet radiation.

1847 Jupiter approach estimates
DateJupiter distanceSource
1847-10-020.015  AU (2.2 million km; 1.4 million mi)Kinoshita [7]
1847-10-060.009 AU (1.3 million km; 0.84 million mi) JPL Horizons [10]

Exploration

Artist's impression of the CRAF mission at 22P/Kopff CRAF.jpg
Artist's impression of the CRAF mission at 22P/Kopff

22P/Kopff was the planned target for the joint NASA/ESA Comet Rendezvous Asteroid Flyby (CRAF) mission. The spacecraft would have launched in February 1996 and after a flyby of Earth and 449 Hamburga reached 22P/Kopff in August 2001. The CRAF mission was developed in tandem with the Cassini–Huygens mission. It was cancelled due to cost overruns in 1992.

Notes

  1. ↑ 2 years, 2 months and 3 days before the 2028 perihelion passage, the comet will pass 0.439 AU (65.7 million km) from Jupiter. [3]
  2. ↑ Around 2–6 October 1847, which was 59 years before discovery, the comet passed about 0.015 AU (2 million km) from Jupiter.

References

  1. 1 2 "22P/Kopff Orbit". Minor Planet Center. Archived from the original on 23 February 2025. Retrieved 20 April 2025.
  2. 1 2 3 4 "Horizons Batch for 22P/Kopff (90000340) on 2028-Jun-28" (Perihelion occurs when rdot flips from negative to positive). JPL Horizons. Archived from the original on 17 June 2022. Retrieved 16 June 2022. (JPL#K222/6 Soln.date: 2022-Jun-08)
  3. 1 2 3 4 5 "22P/Kopff – JPL Small-Body Database Lookup". ssd.jpl.nasa.gov. Jet Propulsion Laboratory . Retrieved 27 October 2014.
  4. 1 2 G. Tancredi; J. A. Fernández; H. Rickman; J. Licandro (2006). "Nuclear magnitudes and the size distribution of Jupiter family comets". Icarus. 182 (2): 527–549. Bibcode:2006Icar..182..527T. doi:10.1016/j.icarus.2006.01.007.
  5. ↑ M. M. Knight; R. Kokotanekova; N. H. Samarasinha (2023). "Physical and Surface Properties of Comet Nuclei from Remote Observations". arXiv: 2304.09309 [astro-ph.EP].
  6. ↑ S. Yoshida. "22P/Kopff". www.aerith.net. Retrieved 24 February 2010.
  7. 1 2 3 "22P at Kazuo Kinoshita's Comets". 13 February 2014.
  8. 1 2 3 4 G. W. Kronk. "22P/Kopff". Cometography.com. Retrieved 25 February 2010.
  9. ↑ S. Yoshida. "22P/Kopff (1996)". www.aerith.net. Retrieved 25 February 2010.
  10. ↑ "Horizons: 22P/Kopff #90000324 (1906-1933) on 1847-Oct-06". JPL Horizons . Retrieved 28 October 2025.
Numbered comets
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