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OverviewDiscovery of a comet, that is finding a new comet nobody has ever known before for the first time in the world. Some comets are rotating around the Sun and returns repeatedly. They are called periodic comets. It is not a discovery if you catch a returning periodic comet. But actually, it is often impossible to predict the return of a periodic comet because the orbital elements are uncertain or it has been lost for a long time. Such a periodic comet comes to be discovered several times whenever it returns. When was such a periodic comet discovered indeed? Here I consider the definition of "discovery" of a periodic comet based on the past cases. I also derive and verify the naming rule of a periodic comet from this definition of "discovery". AnalysisDiscovery of a periodic cometAnalyzing the cases of past periodic comet discoveries, I derive the definition of "discovery" of a periodic comet as follows.
Note that here I derive the definition to determine only one apparition recognized as "discovery" as a periodic comet among many recorded apparitions. I do not describe on the priority among discoverers in one apparition. In this definition, "discovery" as a periodic comet does not mean the time when the object was found for the first time in the world. There can be some records of apparitions before the "discovery". In this definition, "discovery" as a periodic comet does not coincide with the time when people actually become aware of the comet. For example, the "discovery" as a periodic comet of Comet D/1977 C1 ( Skiff-Kosai ) is in 1976 based on this definition, however, it was announced in 1986. The perihelion passage in 1984 is a return after the "discovery", but actually, nobody knew about this comet at that time. Naming of a periodic cometBased on the definition of "discovery" as a periodic comet mentioned above, I derive the definition of naming of a periodic comet as follows.
ConsiderationHere I evaluate the definition mentioned above on the periodic comets which have been discovered several times, and verify the definition. 1P/HalleyAll apparitions were recorded since 240 B.C. But the ancient apparitions were only recorded. The orbital elements were calculated in the Middle Ages, but they were parabolic and no periodicity was calculated. After the apparition in 1682, Halley identified three comets, C/1531 P1, C/1607 S1, C/1682 Q1, and calculated the periodicity for the first time. Therefore it was discovered as a periodic comet at the apparition in 1682. 2P/EnckeIt was discovered in 1786 by Mechain, in 1795 by Herschel, in 1805 by Pons, Huth, Bouvard, in 1818 by Pons respectively. After the apparition in 1819, Encke identified these comets and calculated the periodicity for the first time. Therefore it was discovered as a periodic comet at the apparition in 1819. 3D/BielaIt was discovered in 1772 by Montaigne, in 1805 by Pons, in 1826 by Biela respectively. Gauss has identified the two comets in 1772 and 1805, and calculated the periodicity already in 1806. Therefore it was discovered as a periodic comet at the apparition in 1805, discovered by Pons. The discovery in 1826 by Biela is recognized as recovery. This definition derives the name of this comet should be 3D/Montaigne-Pons-Biela. 6P/d'ArrestComet in 1678 discovered by La Hire was identified with 6P/d'Arrest in 1990. No periodicity was calculated for the comet in 1678. Therefore it was discovered as a periodic comet at the apparition in 1851, discovered by d'Arrest, and the name of La Hire was deleted. 7P/Pons-WinneckeIt was discovered in 1819 by Pons, in 1858 by Winnecke respectively. They were identified at the discovery in 1858. No periodicity was calculated in 1819. Therefore it was discovered as a periodic comet at the apparition in 1858, discovered by Winnecke. 8P/TuttleIt was discovered in 1790 by Mechain, in 1858 by Tuttle respectively. They were identified at the discovery in 1858. No periodicity was calculated in 1790. Therefore it was discovered as a periodic comet at the apparition in 1858, discovered by Tuttle. This definition derives the name of this comet should be 8P/Mechain-Tuttle. 11P/Tempel-Swift-LINEARIt was discovered in 1869 by Tempel. The periodicity was calculated. Therefore it was discovered as a periodic comet at that time. The discovery in 1880 by Swift is recognized as recovery. The names of the rediscoverers must not be added to the comet in 2001. Therefore the name of this comet should be 11P/Tempel-Swift. 12P/Pons-BrooksIt was discovered in 1812 by Pons. The periodicity was calculated. Therefore it was discovered as a periodic comet at that time. The discovery in 1883 by Brooks is recognized as recovery. 18D/Perrine-MrkosIt was discovered in 1869 by Perrine. The periodicity was calculated. Therefore it was discovered as a periodic comet at that time. The discovery in 1955 by Mrkos is recognized as recovery. 21P/Giacobini-ZinnerIt was discovered in 1900 by Giacobini. The periodicity was calculated. Therefore it was discovered as a periodic comet at that time. The discovery in 1913 by Zinner is recognized as recovery. 23P/Brorsen-MetcalfIt was discovered in 1847 by Brorsen. The periodicity was calculated. Therefore it was discovered as a periodic comet at that time. The discovery in 1919 by Metcalf is recognized as recovery. 26P/Grigg-SkjellerupIt was discovered in 1902 by Grigg, in 1922 by Skjellerup respectively. They were identified at the discovery in 1922. No periodicity was calculated in 1902. Therefore it was discovered as a periodic comet at the apparition in 1922, discovered by Skjellerup. 27P/CrommelinIt was discovered in 1818 by Pons, in 1873 by Coggia, Winnecke, in 1928 by Yamasaki, Forbes respectively. No periodicity was calculated in 1818. But in 1873, the comets in 1818 and 1873 were identified and the periodicity was calculated. Therefore it was discovered as a periodic comet at the apparition in 1873, discovered by Coggia, Winnecke. Not similar to the cases of 1P/Halley and 2P/Encke, Crommelin researched the orbit after it was discovered as a periodic comet. Therefore, this definition derives the name of this comet should be 27P/Pons-Coggia-Winnecke-Yamasaki-Forbes. 35P/Herschel-RigolletIt was discovered in 1788 by Herschel, in 1939 by Rigollet respectively. They were identified at the discovery in 1939. No periodicity was calculated in 1788. Therefore it was discovered as a periodic comet at the apparition in 1939, discovered by Rigollet. 36P/WhippleAsteroid 1925 QD discovered by Shajn was identified with 36P/Whipple in 1987. No periodicity was calculated for Asteroid 1925 QD. Therefore it was discovered as a periodic comet at the apparition in 1933, discovered by Whipple, and the name of Shajn was rejected. 38P/Stephan-OtermaIt was discovered in 1867 by Stephan. The periodicity was calculated. Therefore it was discovered as a periodic comet at that time. The discovery in 1942 by Oterma is recognized as recovery. 41P/Tuttle-Giacobini-KresakIt was discovered in 1858 by Tuttle, in 1907 by Giacobini, in 1951 by Kresak respectively. The periodicity was calculated in 1858. Therefore it was discovered as a periodic comet at that time. The discoveries in 1907 by Giacobini and in 1951 by Kresak are recognized as recovery. 43P/Wolf-HarringtonIt was discovered in 1924 by Wolf. The periodicity was calculated. Therefore it was discovered as a periodic comet at that time. The discovery in 1951 by Harrington is recognized as recovery. 54P/de Vico-Swift-NEATIt was discovered in 1844 by de Vico. The periodicity was calculated. Therefore it was discovered as a periodic comet at that time. The discovery in 1894 by Swift is recognized as recovery. The names of the rediscoverers must not be added to the comet in 2002. Therefore the name of this comet should be 54P/de Vico-Swift. 64P/Swift-GehrelsIt was discovered in 1889 by Swift. The periodicity was calculated. Therefore it was discovered as a periodic comet at that time. The discovery in 1973 by Gehrels is recognized as recovery. 72P/Denning-FujikawaIt was discovered in 1881 by Denning. The periodicity was calculated. Therefore it was discovered as a periodic comet at that time. The discovery in 1978 by Fujikawa is recognized as recovery. 74P/Smirnova-ChernykhAsteroid 1967 EU was identified with 74P/Smirnova-Chernykh in 1980s. No periodicity was calculated for Asteroid 1967 EU. Therefore it was discovered as a periodic comet at the apparition in 1975, discovered by Smirnova, Chernykh, and the names of the discoverers of Asteroid 1967 EU were rejected. 79P/du Toit-HartleyIt was discovered in 1945 by du Toit. The periodicity was calculated. Therefore it was discovered as a periodic comet at that time. The discovery in 1982 by Hartley is recognized as recovery. 80P/Peters-HartleyIt was discovered in 1846 by Peters. The periodicity was calculated. Therefore it was discovered as a periodic comet at that time. The discovery in 1982 by Hartley is recognized as recovery. 97P/Metcalf-BrewingtonIt was discovered in 1906 by Metcalf. The periodicity was calculated. Therefore it was discovered as a periodic comet at that time. The discovery in 1991 by Brewington is recognized as recovery. 104P/Kowal 2Comet in 1973 discovered by Boethin was identified with 104P/Kowal 2 in 2003. No periodicity was calculated for the comet in 1973. Therefore it was discovered as a periodic comet at the apparition in 1979, discovered by Kowal, and the name of Boethin was rejected. 107P/(4015) Wilson-HarringtonIt was discovered in 1949 by Wilson, Harrington as a comet D/1949 W1. Then it was discovered in 1979 by Helin as an asteroid 1979 VA. Because the orbit of D/1949 W1 was uncertain and the comet had been lost, they were considered as different objects. The period of Asteroid 1979 VA was concluded and it was registered as (4015). After that, Asteroid (4015) was identified with Comet D/1949 W1. However, Cunningham has calculated the periodicity already in 1949. Therefore it was discovered as a periodic comet at that time, and the name of Helin was rejected. 109P/Swift-TuttleComet in 1737 discovered by Kegler was identified with Comet Swift-Tuttle in 1970s. No periodicity was calculated for the comet in 1737. Therefore it was discovered as a periodic comet at the apparition in 1869, discovered by Swift, Tuttle, and the name of Kegler was deleted. 122P/de VicoIt was discovered in 1995 by Nakamura, Tanaka, Utsunomiya, Seki, Machholz. But it was identified with Comet D/de Vico discovered in 1846. The periodicity was calculated in 1846. Therefore it was discovered as a periodic comet at that time, and the names of rediscoverers in 1995 were rejected. 133P/(7968) Elst-PizarroAsteroid 1979 OW7 was identified with 133P/Elst-Pizarro later. No periodicity was calculated for Asteroid 1979 OW7. The period of this asteroid was concluded and it was registered as (7968) after the identification. Therefore it was discovered as a periodic comet at the apparition in 1996, discovered by Elst, Pizarro, and the names of the discoverers of Asteroid 1979 OW7 were rejected. 139P/Vaisala-OtermaAsteroid 1939 TN discovered by Vaisala, Oterma was revealed to be a comet in 1981. After that, Asteroid 1998 WG22 discovered by LINEAR was identified with 1939 TN. The periodicity was calculated already in 1981. Therefore it was discovered as a periodic comet at the apparition in 1939, discovered by Vaisala, Oterma, and the name of LINEAR was rejected. 146P/Shoemaker-LINEARThe names of the rediscoverers must not be added to the comet in 2000. Therefore the name of this comet should be 146P/Shoemaker. 148P/Anderson-LINEARIt was discovered in 1963 by Anderson. The periodicity was calculated. Therefore it was discovered as a periodic comet at that time. The names of the rediscoverers must not be added to the comet in 2000. Therefore the name of this comet should be 148P/Anderson. 153P/Ikeya-ZhangComet in 2002 discovered by Ikeya, Zhang, Raymundo was identified with Comet in 1661 observed by Hevelius. No periodicity was calculated for the comet in 1661. Therefore it was discovered as a periodic comet at the apparition in 2002. The comet in 1661 had no official name. But it was identified at the same time when this comet was discovered as a periodic comet. Therefore, if it had been named after Hevelius, the name of this comet would have been 153P/Hevelius-Ikeya-Zhang. 156P/Russell-LINEARIt was discovered in 1986 by Russell as a comet, in 1993 by Shoemaker as Asteroid 1993 WU, in 2000 as Asteroid 2000 QD181 respectively. The comet in 1986 was not confirmed whether real or false. Asteroid 1993 WU had been lost because the orbital elements were uncertain. Therefore these three were considered as different objects at the discovery of 2000 QD181. In 2001, Asteroids 1993 WU and 2000 QD181 were identified. But the orbital elements were not concluded and the asteroid was not numbered at that time. In 2003, this asteroid was identified with the comet in 1986. Then this object was discovered as a periodic comet by this identification. Therefore it was discovered as a periodic comet at the apparition in 2000, discovered by LINEAR. No periodicity was calculated in 1986. The comet in 1986 was identified at the same time when the object was discovered as a periodic comet. Therefore the name of this comet is definitely 156P/Russell-LINEAR. 158P/Kowal-LINEARIt was discovered in 1979 by Kowal as Comet C/1979 O1, in 2001 by LINEAR as Asteroid 2001 RG100 respectively. In 2003, the asteroid in 2001 was revealed to be a comet, and it was identified with the comet in 1979. No periodicity was calculated in 1979. Therefore it was discovered as a periodic comet at the apparition in 2001, discovered by LINEAR. The comet in 1979 was identified at the same time when the object was discovered as a periodic comet. Therefore the name of this comet is definitely 158P/Kowal-LINEAR. 169P/NEATIt was discovered in 2002 by NEAT as Asteroid 2002 EX12. It was revealed to be a comet in 2005. It was not accidentally discovered as a new comet. Therefore it was discovered as a periodic comet at the apparition in 2001, although originally discovered as an asteroid. 174P/(60558) EcheclusIt was discovered in 2000 by Spacewatch as Asteroid 2000 EC98. After it was registered as Asteroid (60558), it was revealed to be a comet in 2005. It was not accidentally discovered as a new comet. Therefore it was discovered as a periodic comet at the apparition in 2015, although originally discovered as an asteroid. However, it is in the same apparition in 2015, when it was revealed to be a comet. 176P/(118401) LINEARIt was discovered in 1999 by LINEAR as Asteroid 1999 RE70. After it was registered as Asteroid (118401), it was revealed to be a comet in 2006. It was not accidentally discovered as a new comet. Therefore it was discovered as a periodic comet at the apparition in 2000, although originally discovered as an asteroid. 206P/Barnard-BoattiniIt was discovered in 1892 by Barnard. The periodicity was calculated. Therefore it was discovered as a periodic comet at that time. The names of the rediscoverers must not be added to the comet in 2008. Therefore the name of this comet should be 206P/Barnard. 226P/Pigott-LINEAR-KowalskiIt was discovered in 1783 by Pigott. The periodicity was calculated. Therefore it was discovered as a periodic comet at that time. When it was rediscovered in 2003 by LINEAR, the identification with a comet discovered in 1783 by Pigott was not concluded. When it was rediscovered in 2009 by Kowalski, the identification was concluded. The names of the rediscoverers must not be added to the comet in 2003. Therefore the name of this comet should be 226P/Pigott. 271P/van Houten-LemmonIt was discovered in 1960 by van Houten. The periodicity was calculated. Therefore it was discovered as a periodic comet at that time. The names of the rediscoverers must not be added to the comet in 2012. Therefore the name of this comet should be 271P/van Houten. 274P/Tombaugh-TenagraIt was discovered in 1931 by Tombaugh. The periodicity was calculated. Therefore it was discovered as a periodic comet at that time. The names of the rediscoverers must not be added to the comet in 2012. Therefore the name of this comet should be 274P/Tombaugh. 302P/Lemmon-PanSTARRSWhen it was discovered as a comet by PanSTARRS in 2014, it was identified with Asteroid 2007 RJ236 discovered by Lemmon in 2007. No periodicity was calculated for Asteroid 2007 RJ236. The periodicity was calculated by this identification, and it was recognized as a periodic comet. Therefore it was discovered as a periodic comet at the apparition in 2016, discovered by PanSTARRS. It was identified at the same time when the object was discovered as a periodic comet. Therefore the name of this comet is definitely 302P/Lemmon-PanSTARRS. 351P/Wiegert-PanSTARRSIt was discovered as a comet in 2016 by PanSTARRS. Then the periodicity was calculated, and it was identified with a comet discovered by Wiegert in 2007. No periodicity was calculated in 2007. Therefore it was discovered as a periodic comet at the apparition in 2015, discovered by PanSTARRS. The comet in 2007 was identified at the same time when the object was discovered as a periodic comet. Therefore the name of this comet is definitely 351P/Wiegert-PanSTARRS. 407P/PanSTARRS-FulsA comet discovered in 2013 by PanSTARRS and a comet discovered in 2019 by Fuls were identified in 2020. The periodicity was calculated in 2013. Therefore it was discovered as a periodic comet in 2013. Therefore the name of this comet should be PanSTARRS. 437P/Lemmon-PanSTARRSWhen it was discovered as a comet by PanSTARRS in 2021, it was identified with Asteroid 2011 UE215 discovered by Lemmon in 2011. No periodicity was calculated for Asteroid 2011 UE215. The periodicity was calculated by this identification, and it was recognized as a periodic comet. Therefore it was discovered as a periodic comet at the apparition in 2021, discovered by PanSTARRS. It was identified at the same time when the object was discovered as a periodic comet. Therefore the name of this comet is definitely 437P/Lemmon-PanSTARRS. This comet was announced as 437P/PanSTARRS at fist, but later, it was renamed as 437P/Lemmon-PanSTARRS. 443P/PanSTARRS-ChristensenWhen it was discovered as a comet by Christensen in 2022, the periodicity was calculated. And it was announced as P/2022 E1 ( Christensen ). After that, it was identified with Asteroid 2015 PO210 discovered by PanSTARRS in 2015. No periodicity was calculated for Asteroid 2015 PO210. And it was identified after it was discovered as a periodic comet P/2022 E1 ( Christensen ). Therefore the name of this comet should be Christensen. P/2016 PM1 = P/2010 LK36 = P/2022 C4 ( WISE-PanSTARRS )When it was discovered as an asteroid by PanSTARRS in 2016, it was identified with Asteroid 2010 LK36 discovered by WISE in 2010, and the periodicity was calculated. But it was not revealed to a comet at tht time. It was revealed to be a comet at the apparition in 2022. It was not accidentally discovered as a new comet. Therefore it was discovered as a periodic comet at the apparition in 2016, although originally discovered as an asteroid. It was identified at the same time when the object was discovered as a periodic comet. Therefore the name of this comet is definitely P/WISE-PanSTARRS. P/2000 OZ21 = P/2022 M1 ( LONEOS-PanSTARRS )When it was discovered as a comet by PanSTARRS in 2022, the periodicity was calculated. And it was announced as P/2022 M1 ( PanSTARRS ). After that, it was identified with Asteroid 2000 OZ21 discovered by LONEOS in 2000. The periodicity of Asteroid 2000 OZ21 was calculated in 2000. Therefore it was discovered as a periodic comet in 2000. Therefore the name of this comet should be LONEOS. AppendixDifference between naming by this definition and official name
Periodic comets including the recoverers' names
Rediscoveries of periodic comets since 1995
References
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