Lost comet - AbsoluteAstronomy.com

A lost comet is a previously discovered comet

Comet

A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...

that has been missed at its most recent perihelion passage, generally because there is not enough data to reliably calculate the comet's orbit and predict its location.

Lost comets can be compared to lost asteroids

Lost asteroids

Lost asteroids or lost planets are asteroids that observers lose track of after discovering. Many early lost asteroids were rediscovered in the 1980s and 1990s, but a number of asteroids and other types of small Solar System bodies continue to be lost...

, although calculation of cometary orbits differs because of nongravitational forces that can affect comets, such as emission of jets of gas from the nucleus. Some astronomers have specialized in this area, such as Brian G. Marsden

Brian G. Marsden

Brian Geoffrey Marsden was a British astronomer born in Cambridge, England, and educated at The Perse School in Cambridge, New College, Oxford and Yale University. Dr...

who successfully predicted the 1992 return of the once-lost periodic comet Swift–Tuttle

Comet Swift–Tuttle

Comet Swift–Tuttle is a comet that was independently discovered by Lewis Swift on July 16, 1862 and by Horace Parnell Tuttle on July 19, 1862...

Reasons for loss

There are a number of reasons why a comet might be missed by astronomers during subsequent apparitions. Firstly, cometary orbits may be perturbed

Perturbation (astronomy)

Perturbation is a term used in astronomy in connection with descriptions of the complex motion of a massive body which is subject to appreciable gravitational effects from more than one other massive body....

by interaction with the giant planets, such as Jupiter

Jupiter

Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...

. This, along with nongravitational forces, can result in changes to the date of perihelion. Alternatively, it is possible that the interaction of the planets with a comet can move its orbit too far from the Earth to be seen or even eject it from the Solar System

Solar System

The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...

, as is believed to have happened in the case of Lexell's Comet

Lexell's Comet

D/1770 L1, popularly known as Lexell's Comet after its orbit computer Anders Johan Lexell, was a comet discovered by astronomer Charles Messier in June 1770. It is notable for having passed closer to the Earth than any other comet in recorded history, approaching to a distance of only...

. As some comets periodically undergo "outbursts" or flares in brightness, it may be possible for an intrinsically faint comet to be discovered during an outburst and subsequently lost.
Comets can also run out of volatiles. Eventually most of the volatile material contained in a comet nucleus evaporates away, and the comet becomes a small, dark, inert lump of rock or rubble, an extinct comet that can resemble an asteroid

Asteroid

Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...

(see also Comets#Fate of comets). This may have occurred in the case of 5D/Brorsen

5D/Brorsen

5D/Brorsen is a comet discovered February 26, 1846, by the Danish astronomer Theodor Brorsen....

, which was considered by Marsden to have probably "faded out of existence" in the late 19th century.

Comets are in some cases known to have disintegrated during their perihelion passage, or at other points during their orbit. The most well-known example is Biela's Comet, which was observed to split into two components before disappearing after its 1852 apparition. In modern times 73P/Schwassmann–Wachmann has been observed in the process of breaking up.

Occasionally, the discovery of an object turns out to be a rediscovery of a previously lost object, which can be determined by calculating its orbit and matching calculated positions with the previously recorded positions. In the case of lost comets this is especially tricky. For example, the comet 177P/Barnard (also P/2006 M3), discovered by Edward Emerson Barnard on June 24, 1889, was rediscovered after 116 years in 2006. On July 19, 2006, 177P came within 0.36 AU

Astronomical unit

An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....

of the Earth.

Comets can be gone but not considered lost, even though they may not be expected back for hundreds or even thousands of years. With more powerful telescopes it has become possible to observe comets for longer periods of time after perihelion. For example, Comet Hale–Bopp was observable with the naked eye about 18 months after its approach in 1997. It is expected to remain observable with large telescopes until perhaps 2020, by which time it will be nearing 30th magnitude

Apparent magnitude

The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...

.

Comets that have been lost or which have disappeared have names beginning with a "D" according to current IAU conventions.

Table

Comets are typically observed on a periodic return. When they do not they are sometimes found again, while other times they may break up into fragments. These fragments can sometimes be further observed, but the comet is no longer expected to return. Other times a Comet will not be considered lost until it does not appear at a predicted time. Comets may also collide with another object, such as Comet Shoemaker–Levy 9, which collided with Jupiter

Jupiter

in 1994.

Name(s)	Initially Discovered	Recovered or Lost	Fate/Status
34D/Gale 34D/Gale Comet Gale is a periodic comet in the Solar System discovered by Walter Frederick Gale on June 7, 1927.The second apparition was calculated for 1938, but Gale failed to find it, however, it was recalculated by Leland E...	1927	1938	Lost since 1938
206P/Barnard–Boattini	1892	2008	Found since 2008
15P/Finlay 15P/Finlay Comet Finlay is a periodic comet in our solar system discovered by William Henry Finlay on September 26, 1886....	1886–1926	1953	Found since 1953
107P/Wilson–Harrington	1949	1992	Found since 1992
73P/Schwassmann–Wachmann	1930	?	Breakup (1995)
25D/Neujmin 25D/Neujmin Comet 25D/Neujmin, otherwise known as Comet Neujmin 2, is a periodic comet in the solar system discovered by Grigory N. Neujmin on February 24, 1916....	1916		Considered lost since 1927
69P/Taylor 69P/Taylor Comet Taylor, is a periodic comet in the solar system, first discovered by Clement J. Taylor on November 24, 1915.George van Biesbroeck and E. E. Barnard observed that the comet was split into two distinct nucleus, but this was not seen after March 16.The comet was predicted to return in 1922,...	1915	1976, 1984, 1990, 1998
11P/Tempel–Swift–LINEAR	1908	2001	Found since 2001
113P/Spitaler 113P/Spitaler Comet Spitaler is a periodic comet in the solar system discovered by Rudolf Ferdinand Spitaler on November 17, 1890 whilst attempting to observe Comet Zona .Spitaler, together with G. M. Searle, J. F. Tennant, and J. R...	1897	1993	Found since 1994
205P/Giacobini (D/1896 R2)	1896	2008
18D/Perrine–Mrkos	1896	1955	Lost
17P/Holmes 17P/Holmes Comet Holmes is a periodic comet in our solar system, discovered by the British amateur astronomer Edwin Holmes on November 6, 1892...	1892–1906	1964	Found Since 1964
177P/Barnard	1889	2006	Recovered after 116 years
20D/Westphal 20D/Westphal 20D/Westphal is a periodic comet in our solar system, originally discovered by the German astronomer J. G. Westphal on July 24, 1852....	1852	1913	Lost
5D/Brorsen 5D/Brorsen 5D/Brorsen is a comet discovered February 26, 1846, by the Danish astronomer Theodor Brorsen....	1846	1857, 1868, 1879	Lost since 1879
54P/de Vico–Swift–NEAT	1844	1894, 1965, 2002	Found since 2002
27P/Crommelin 27P/Crommelin Comet Crommelin, also known as Comet Pons-Coggia-Winnecke-Forbes, is a periodic comet in the solar system named after the British astronomer Andrew C. D. Crommelin who calculated its orbit in 1930...	1818	1873, 1928	Found since 1928
3D/Biela	1772	1852	Broke up (1846), Andromedids Andromedids The Andromedids meteor shower is associated with the comet 3D/Biela, the showers occurring as the earth's orbit passes through the tail of the comet...
D/1770 L1 (Lexell) Lexell's Comet D/1770 L1, popularly known as Lexell's Comet after its orbit computer Anders Johan Lexell, was a comet discovered by astronomer Charles Messier in June 1770. It is notable for having passed closer to the Earth than any other comet in recorded history, approaching to a distance of only...	1770		Lost since 1770

Disintegration

External links

Lost periodic comets on Maik Meyer's home page

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.

Reasons for loss

Table

Disintegration

See also

External links