A lost comet is one which was not detected during its most recent perihelion passage. This generally happens when data is insufficient to reliably calculate the comet's location or if the solar elongation is unfavorable near perihelion passage. The D/ designation is used for a periodic comet that no longer exists or is deemed to have disappeared. [1]
Lost comets can be compared to lost asteroids (lost minor planets), although calculation of comet orbits differs because of nongravitational forces, such as emission of jets of gas from the nucleus. Some astronomers have specialized in this area, such as Brian G. Marsden, who successfully predicted the 1992 return of the once-lost periodic comet Swift–Tuttle.
There are a number of reasons why a comet might be missed by astronomers during subsequent apparitions. Firstly, cometary orbits may be perturbed by interaction with the giant planets, such as Jupiter. 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, as is believed to have happened in the case of Lexell's Comet. 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, [2] an extinct comet that can resemble an asteroid (see Comets § Fate of comets). This may have occurred in the case of 5D/Brorsen, which was considered by Marsden to have probably "faded out of existence" in the late 19th century. [3]
Comets are in some cases known to have disintegrated during their perihelion passage, or at other points during their orbit. The best-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. [4]
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, [5] and the James Webb Space Telescope observed Hale–Bopp in 2022, 25 years since last approach, when it was 46.2 AU from the Sun. [6]
Comets that have been lost or which have disappeared have names beginning with a D, according to current naming conventions.
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 in 1994.
Name(s) | Initially discovered | Period (years) | Last seen | Recovered | Fate |
---|---|---|---|---|---|
D/1766 G1 (Helfenzrieder) | 1766 | 4.35 | Uncertain orbit. Possibly perturbed by Jupiter after 1766 | ||
D/1770 L1 (Lexell) | 1770 | 5.6 | Probably lost due to a 1779 close encounter with Jupiter which might have greatly perturbed the orbit or even ejected the comet from the Solar System. The asteroid (529688) 2010 JL33 is most likely its inert remnant. | ||
3D/Biela | 1772 | 6.6 | 1852 | Broke up in two fragments (1846), then thousands, creating the Andromedids meteor shower | |
27P/Crommelin | 1818 | 27.9 | 1873 | 1928 | Three independent discoveries linked by Crommelin in 1930 |
289P/Blanpain | 1819 | 5.2 | 2003 | Lost since 1819 discovery due to faintness; rediscovered in 2003 thanks to good viewing conditions; first identified as asteroid 2003 WY25, subsequently matched to the 1819 comet after 184 years and 35 orbits; confirmed by observations in 2013 and 2014 near perihelion; probable source of the Phoenicids meteor shower observed since 1956 | |
273P/Pons–Gambart | 1827 | 180 | 2012 | Period of roughly 64±10 years originally computed in 1917 was wrong; rediscovered after 185 years in a single orbit; possibly matches a Chinese observation in 1110 | |
54P/de Vico–Swift–NEAT | 1844 | 7.3 | 1894, 1965 | 2002 | Lost several times due to perturbations by Jupiter |
122P/de Vico | 1846 | 74.4 | 1995 | Not observed on first predicted return in 1921; recovered in 1995 after 149 years and 2 orbits | |
5D/Brorsen | 1846 | 5.5 | 1879 | Lost since 1879 despite good orbit computations | |
80P/Peters–Hartley | 1846 | 8.1 | 1982 | Recovered in 1982 after 136 years and 17 orbits; regularly observed since then | |
20D/Westphal | 1852 | 61.9 | 1913 | Expected in 1976 but not observed; next possible return in 2038 | |
109P/Swift–Tuttle | 1862 | 133.3 | 1992 | Recovered after 130 years as predicted in 1971 by Brian G. Marsden; retroactively matched to observations of 1737 in Europe and 188 AD and 68 BC in China; source of the Perseids meteor shower | |
55P/Tempel–Tuttle | 1865 | 33.2 | 1965 | Recovered in 1965 after 99 years and 3 orbits; matches earlier observations of 1366 and 1699; source of the Leonids meteor shower | |
11P/Tempel–Swift–LINEAR | 1869 | 6.4 | 1908 | 2001 | Recovered in 2001 after 93 years and 15 orbits; not observed in 2008 due to solar conjunction but seen again in 2014 as predicted |
X/1872 X1 (Pogson) | 1872 | Originally mistaken as the recovery of Biela's Comet | |||
72P/Denning–Fujikawa | 1881 | 9.0 | 1978 | 2014 | Recovered in 1978 after 97 years and 11 orbits, then lost again and recovered in 2014 after 4 more orbits |
X/1882 K1 (Tewfik) | 1882 | Only seen once during the solar eclipse of May 17, 1882 | |||
D/1884 O1 (Barnard) | 1884 | 5.39 | Possibly disintegrated after an outburst | ||
15P/Finlay | 1886 | 6.5 | 1926 | 1953 | Regularly observed since 1953 |
D/1886 K1 (Brooks) | 1886 | 5.44 | Uncertain orbital period. Perihelion increased from 1.3 to 1.9 AU | ||
177P/Barnard | 1889 | 118.8 | 2006 | Recovered after 117 years [4] in a single orbit | |
206P/Barnard–Boattini | 1892 | 5.8 | 2008 | Recovered in 2008 after 116 years and 20 orbits; not seen on predicted return in 2014; not observed in 2021 due to low magnitude; next perihelion in 2027 | |
17P/Holmes | 1892 | 6.9 | 1906 | 1964 | Regularly observed since 1964; large outburst in 2007 |
489P/Denning | 1894 | 9.4 | 2007 | 2024 | Identified in 2024 as the asteroid 2007 HE4 |
D/1895 Q1 (Swift) | 1895 | 7.2 | 1896 | Several perturbations by Jupiter. Shattered remains possibly encountered by Mariner 4 in 1967 | |
205P/Giacobini (D/1896 R2) | 1896 | 6.7 | 2008 | Recovered in 2008 after 112 years and 17 orbits; seen in 2015 as predicted; three visible fragments | |
18D/Perrine–Mrkos | 1896 | 6.75 | 1909, 1968 | 1955 | Lost after 1909, recovered in 1955 and lost again since 1968 |
113P/Spitaler | 1890 | 7.1 | 1993 | Recovered in 1993 after 103 years and 15 orbits; regularly observed since 1994 perihelion | |
97P/Metcalf–Brewington | 1906 | 10.5 | 1991 | Recovered in 1991 after 84 years and 11 orbits; orbital period lengthened by Jupiter in 1993 | |
69P/Taylor | 1915 | 6.95 | 1976 | Recovered in 1976 after 61 years and 9 orbits; regularly observed since 1977 perihelion | |
25D/Neujmin | 1916 | 5.4 | 1927 | Only seen twice; lost since 1927 | |
D/1918 W1 (Schorr) | 1918 | 6.66 | Perihelion increased from 1.9 to 3.0 AU | ||
C/1921 H1 (Dubiago) | 1921 | 70.0 | Was not observed on its 1982 apparition | ||
34D/Gale | 1927 | 11.0 | 1938 | Only seen twice; lost since 1938 | |
73P/Schwassmann–Wachmann | 1930 | 5.4 | 1979 | Broke up into 4 fragments in 1995 and dozens in 2006, yielding the Tau Herculids meteor shower | |
57P/du Toit–Neujmin–Delporte | 1941 | 6.4 | 1970 | Recovered in 1970 after 29 years and 5 orbits; observed regularly since 1983 | |
107P/Wilson–Harrington | 1949 | 4.3 | 1992 | Lost for 30 years; rediscovered as a Mars-crosser asteroid in 1979; equated with the lost comet in 1992 while searching for precovery images | |
D/1952 B1 (Harrington–Wilson) | 1952 | 6.35 | Intrinsically faint. Perihelion increased from 1.65 to 1.9 AU | ||
D/1960 S1 (van Houten) | 1960 | 15.61 | Uncertain orbit | ||
271P/van Houten–Lemmon | 1966 | 18.5 | 2012 | First discovered on plates from 1960; recovered in 2012 after 3 orbits; perihelion in 2013 | |
85D/Boethin | 1975 | 11.2 | 1986 | Only seen twice; lost since 1986 (expected in 1997 and 2008 but not observed), officially demoted in 2017 [7] | |
75D/Kohoutek | 1975 | 6.6 | 1988 | Only seen three times; lost since 1988 | |
D/1977 C1 (Skiff–Kosai) | 1977 | 7.54 | Perihelion decreased slightly | ||
157P/Tritton | 1978 | 6.4 | 2003 | Recovered in 2003 after 25 years and 4 orbits; regularly observed since then | |
D/1978 R1 (Haneda–Campos) | 1978 | 5.98 | Only seen once. Intrinsically faint, perihelion increased from 1.1 to 1.3 AU | ||
83D/Russell | 1979 | 6.1 | 1985 | Only seen twice; lost since 1985, probably due to a close encounter with Jupiter in 1988 | |
449P/Leonard | 1987 | 6.8 | 2020 | Identified in 2022 as a rediscovery of a previously lost comet, X/1987 A2 | |
D/1993 F2 (Shoemaker–Levy) | 1993 | 1994 | Fragments collided with Jupiter in July 1994 |
A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or coma surrounding the nucleus, and sometimes a tail of gas and dust gas blown out from the coma. These phenomena are due to the effects of solar radiation and the outstreaming solar wind plasma acting upon the nucleus of the comet. Comet nuclei range from a few hundred meters to tens of kilometers across and are composed of loose collections of ice, dust, and small rocky particles. The coma may be up to 15 times Earth's diameter, while the tail may stretch beyond one astronomical unit. If sufficiently close and bright, a comet may be seen from Earth without the aid of a telescope and can subtend an arc of up to 30° across the sky. Comets have been observed and recorded since ancient times by many cultures and religions.
Comet Hale–Bopp is a long-period comet that was one of the most widely observed of the 20th century and one of the brightest seen for many decades.
Halley's Comet is the only known short-period comet that is consistently visible to the naked eye from Earth, appearing every 72–80 years, though with the majority of recorded apparations occurring after 75–77 years. It last appeared in the inner parts of the Solar System in 1986 and will next appear in mid-2061. Officially designated 1P/Halley, it is also commonly called Comet Halley, or sometimes simply Halley.
Comet Hyakutake is a comet discovered on 31 January 1996. It was dubbed the Great Comet of 1996; its passage to within 0.1 AU (15 Gm) of the Earth on 25 March was one of the closest cometary approaches of the previous 200 years. Reaching an apparent visual magnitude of zero and spanning nearly 80°, Hyakutake appeared very bright in the night sky and was widely seen around the world. The comet temporarily upstaged the much anticipated Comet Hale–Bopp, which was approaching the inner Solar System at the time.
Comet Encke, or Encke's Comet, is a periodic comet that completes an orbit of the Sun once every 3.3 years. Encke was first recorded by Pierre Méchain on 17 January 1786, but it was not recognized as a periodic comet until 1819 when its orbit was computed by Johann Franz Encke. Like Halley's Comet, it is unusual in its being named after the calculator of its orbit rather than its discoverer. Like most comets, it has a very low albedo, reflecting only 4.6% of the light its nucleus receives, although comets generate a large coma and tail that can make them much more visible during their perihelion. The diameter of the nucleus of Encke's Comet is 4.8 km.
12P/Pons–Brooks is a periodic comet with an orbital period of 71 years. Comets with an orbital period of 20–200 years are referred to as Halley-type comets. It is one of the brightest known periodic comets, reaching an absolute visual magnitude of about 5 in its approach to perihelion. Comet Pons-Brooks was conclusively discovered at Marseilles Observatory in July 1812 by Jean-Louis Pons, and on its next appearance in 1883 by William Robert Brooks. However it has been confirmed 12P/Pons–Brooks was observed before the 19th century.
A sungrazing comet is a comet that passes extremely close to the Sun at perihelion – sometimes within a few thousand kilometres of the Sun's surface. Although small sungrazers can completely evaporate during such a close approach to the Sun, larger sungrazers can survive many perihelion passages. However, the strong evaporation and tidal forces they experience often lead to their fragmentation.
The Kreutz sungrazers are a family of sungrazing comets, characterized by orbits taking them extremely close to the Sun at perihelion. At the far extreme of their orbits, aphelion, Kreutz sungrazers can be a hundred times farther from the Sun than the Earth is, while their distance of closest approach can be less than twice the Sun's radius. They are believed to be fragments of one large comet that broke up several centuries ago and are named for German astronomer Heinrich Kreutz, who first demonstrated that they were related. These sungrazers make their way from the distant outer Solar System to the inner Solar System, to their perihelion point near the Sun, and then leave the inner Solar System in their return trip to their aphelion.
5D/Brorsen was a periodic Jupiter-family comet discovered on February 26, 1846, by Danish astronomer Theodor Brorsen. The comet was last seen in 1879 and is now considered lost.
60558 Echeclus is a centaur, approximately 60 kilometers (37 miles) in diameter , located in the outer Solar System. It was discovered by Spacewatch in 2000 and initially classified as a minor planet with provisional designation 2000 EC98 (also written 2000 EC98). Research in 2001 by Rousselot and Petit at the Besançon observatory in France indicated that it was not a comet, but in December 2005 a cometary coma was detected. In early 2006 the Committee on Small Bodies Nomenclature (CSBN) gave it the cometary designation 174P/Echeclus. It last came to perihelion in April 2015, and was expected to reach about apparent magnitude 16.7 near opposition in September 2015.
Comet 322P/SOHO, also designated P/1999 R1, P/2003 R5, P/2007 R5, and P/2011 R4, is the first periodic comet to be discovered using the automated telescopes of the SOHO spacecraft, and second to be given a numbered designation, after 321P/SOHO. JPL Horizons next predicts 322P to come to perihelion on 21 August 2023 at around apparent magnitude 6 and only 3 degrees from the Sun. At perihelion it is six times closer to the Sun than the planet Mercury is at perihelion.
Comet Arend or 50P/Arend is a periodic comet in the Solar System which was discovered on October 4, 1951. It was discovered by astronomer Sylvain Julien Victor Arend at the Royal Observatory of Belgium located in the municipality of Uccle. The comet was illustrated at approximately a magnitude of 14 and also exhibited a nucleus within a coma 14 arc seconds across. From its discovery, the comet has had 7 perihelions with its last return of Earth recorded on November 1, 2007. The comet's next perihelion will be in the year 2024.
Comet Swift–Tuttle is a large periodic comet with a 1995 (osculating) orbital period of 133 years that is in a 1:11 orbital resonance with Jupiter. It fits the classical definition of a Halley-type comet, which has an orbital period between 20 and 200 years. The comet was independently discovered by Lewis Swift on 16 July 1862 and by Horace Parnell Tuttle on 19 July 1862.
Comets have been observed for over 2,000 years. During that time, several different systems have been used to assign names to each comet, and as a result many comets have more than one name.
104P/Kowal, also known as Kowal 2, is a periodic Jupiter-family comet discovered by Charles T. Kowal in 1979. The orbit was confirmed after new sightings in 1991 and 1998.
A hyperbolic asteroid is any sort of asteroid or non-cometary astronomical object observed to have an orbit not bound to the Sun and will have an orbital eccentricity greater than 1 when near perihelion. Unlike hyperbolic comets, they have not been seen out-gassing light elements, and therefore have no cometary coma. Most of these objects will only be weakly hyperbolic and will not be of interstellar origin.
C/2014 UN271 (Bernardinelli–Bernstein), simply known as C/2014 UN271 or Comet Bernardinelli–Bernstein (nicknamed BB), is a large Oort cloud comet discovered by astronomers Pedro Bernardinelli and Gary Bernstein in archival images from the Dark Energy Survey. When first imaged in October 2014, the object was 29 AU (4.3 billion km; 2.7 billion mi) from the Sun, almost as far as Neptune's orbit and the greatest distance at which a comet has been discovered. With a nucleus diameter of at least 120 km (75 mi), it is the largest Oort cloud comet known. It is approaching the Sun and will reach its perihelion of 10.9 AU (just outside of Saturn's orbit) in January 2031. It will not be visible to the naked eye because it will not enter the inner Solar System.