Comet Kopff or 22P/Kopff is a

periodic comet Periodic comets (also known as short-period comets) are comets with orbital periods of less than 200 years or that have been observed during more than a single perihelion passage (e.g. 153P/Ikeya–Zhang). "Periodic comet" is also sometimes us ...

in the

Solar System The Solar System Capitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar ...

. Discovered on August 23, 1906, it was named after

August Kopff August Kopff (February 5, 1882 – April 25, 1960) was a German astronomer and discoverer of several comets and asteroids. Kopff studied and worked in Heidelberg, getting his PhD there in 1906 and he then joined the Humboldt University of Berli ...

who discovered the comet. The comet was missed on its November 1912 return, but was recovered on its June 1919 return and has been seen at every apparition since. Close approaches to

Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousand ...

in 1938 and 1943 decreased the perihelion distance and

orbital period The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting pla ...

. 22P/Kopff’s last

perihelion An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any elli ...

passage was 18 March 2022. On 13 July 2028 it will pass from Earth.

Observations

22P/Kopff was discovered at Königstuhl Observatory on

Heidelberg Heidelberg (; Palatine German: ') is a city in the German state of Baden-Württemberg, situated on the river Neckar in south-west Germany. As of the 2016 census, its population was 159,914, of which roughly a quarter consisted of students ...

, Germany. 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 Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's ...

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. On November 30, 1994,

Carl W. Hergenrother Carl William Hergenrother (born 1973) is an American astronomer and discoverer of minor planets and comets. As credited by the Minor Planet Center, he has discovered and co-discovered 32 numbered asteroids at the Bigelow Sky Survey during 1993� ...

was able to recover the comet at a stellar magnitude of 22.8 using the 1.5-m reflector at the

Catalina Sky Survey Catalina Sky Survey (CSS; obs. code: 703) is an astronomical survey to discover comets and asteroids. It is conducted at the Steward Observatory's Catalina Station, located near Tucson, Arizona, in the United States. CSS focuses on the search ...

. The comet reached magnitude 7 during the 1996 perihelion passage. The

comet nucleus The nucleus is the solid, central part of a comet, once termed a ''dirty snowball'' or an ''icy dirtball''. A cometary nucleus is composed of rock, dust, and frozen gases. When heated by the Sun, the gases sublime and produce an atmosphere ...

is estimated to be 3.0 kilometers in diameter with an

albedo Albedo (; ) is the measure of the diffuse reflection of solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body that refle ...

of 0.05. The nucleus is dark because

hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...

s on the surface have been converted to a dark, tarry like substance by solar

ultraviolet Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation ...

radiation.

References

External links

Orbital simulation
from JPL (Java)
Ephemeris

Elements and Ephemeris for 22P/Kopff
–

Minor Planet Center The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Function T ...

22P/Kopff at CometBase

–

Gary W. Kronk Gary W. Kronk (born 1956) is an American amateur astronomer and writer. Biography Kronk was born in Granite City, Illinois, United States, on March 23, 1956. He developed an interest in space at an early age, during the time of the first manned ...

's Cometography
22P at Kazuo Kinoshita's Comets

– Seiichi Yoshida @ aerith.net {{DEFAULTSORT:Kopff, P022 Periodic comets 0022 Discoveries by August Kopff Comets in 2015 19060823