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. It fits the classical definition of a Halley-type comet with an orbital period between 20 and 200 years, and is also one of the brightest known periodic comets, reaching an absolute visual magnitude ~5 in its approach to perihelion. Comet Pons-Brooks was discovered at Marseilles Observatory in July 1812 by Jean-Louis Pons, and then later recovered in 1883 by William Robert Brooks.
55P/Tempel–Tuttle is a retrograde periodic comet with an orbital period of 33 years. It fits the classical definition of a Halley-type comet with a period of between 20 and 200 years. It was independently discovered by Wilhelm Tempel on December 19, 1865, and by Horace Parnell Tuttle on January 6, 1866.
Comet Grigg–Skjellerup is a periodic comet. It was visited by the Giotto probe in July 1992. The spacecraft came as close as 200 km, but could not take pictures because some instruments were damaged from its encounter with Halley's Comet. The comet next comes to perihelion on 25 December 2023, but will be 1.8 AU from Earth and only 31 degrees from the Sun.
3200 Phaethon, provisionally designated 1983 TB, is an active Apollo asteroid with an orbit that brings it closer to the Sun than any other named asteroid. For this reason, it was named after the Greek myth of Phaëthon, son of the sun god Helios. It is 5.8 km (3.6 mi) in diameter and is the parent body of the Geminids meteor shower of mid-December. With an observation arc of 35+ years, it has a very well determined orbit. The 2017 Earth approach distance of about 10 million km was known with an accuracy of ±700 m.
Comet Giacobini–Zinner is a periodic comet in the Solar System. It was discovered by Michel Giacobini, who observed it in the constellation of Aquarius on December 20, 1900. It was recovered two orbits later by Ernst Zinner, while he was observing variable stars near Beta Scuti on October 23, 1913.
The Ursid (URS) meteor activity begins annually around December 17 and runs for over a week, until the 25th or 26th. This meteor shower is named for its radiant point, which is located near the star Beta Ursae Minoris (Kochab) in the constellation Ursa Minor.
41P/Tuttle–Giacobini–Kresák is a periodic comet in the Solar System. The comet nucleus is estimated to be 1.4 kilometers in diameter.
169/NEAT is a periodic comet in the Solar System. It is the parent body of the alpha Capricornids meteor shower in Late July. 169/NEAT may be related to comet P/2003 T12 (SOHO). It comes to perihelion on 9 July 2022. On 13 July 2022 passed 0.1395 AU (20.87 million km) from Venus. On 11 August 2026 it will pass 0.1672 AU (25.01 million km) from Earth and then come to perihelion on 21 September 2026.
7P/Pons–Winnecke is a periodic Jupiter-family comet with a six-year orbit. Early calculations for the 1921 apparition suggested that the orbit of the comet might collide with Earth in June, but observations on 10 April ruled out an impact. It made a very close approach to Earth in June 1927. The outward migration of perihelion created impressive meteor showers in 1916, 1921 and 1927.
13P/Olbers is a periodic comet with an orbital period of 69 years. It fits the classical definition of a Halley-type comet with. The comet had last been seen in 1956 and the next perihelion is on 30 June 2024.
Comet Finlay is a periodic comet with an orbital period of 6 years discovered by William Henry Finlay on September 26, 1886. The next perihelion passage is July 13, 2021 when the comet will have a solar elongation of 54 degrees at approximately apparent magnitude 10. It last came to perihelion on December 27, 2014, at around magnitude 10. Of the numbered periodic comets, the orbit of 15P/Finlay has one of the smallest minimum orbit intersection distances with the orbit of Earth (E-MOID). In October 2060 the comet will pass about 5 million km from Earth.
45P/Honda–Mrkos–Pajdušáková is a short-period comet discovered by Minoru Honda December 3, 1948. It is named after Minoru Honda, Antonín Mrkos, and Ľudmila Pajdušáková. The object revolves around the Sun on an elliptical orbit with a period of 5.25 years. The nucleus is 1.3 kilometers in diameter. On August 19 and 20, 2011, it became the fifteenth comet detected by ground radar telescope.
Comet Hartley 2, designated as 103P/Hartley by the Minor Planet Center, is a small periodic comet with an orbital period of 6.48 years. It was discovered by Malcolm Hartley in 1986 at the Schmidt Telescope Unit, Siding Spring Observatory, Australia. Its diameter is estimated to be 1.2 to 1.6 kilometres.
255P/Levy, formerly P/2006 T1 and P/2011 Y1, is a periodic comet with an orbital period of 5.25 years. It last came to perihelion on 14 January 2012. During the 2006 passage the comet achieved an apparent magnitude of ~9.5. Levy (PK06T010) was believed to have been recovered on 3 June 2011 at magnitude 19.8, but other observatories were unable to confirm a recovery. It was most likely a false positive because of large residuals. Levy was recovered on 17 December 2011 at magnitude 19.8, and given the second designation 2011 Y1. It was then numbered.
209P/LINEAR is a periodic comet with an orbital period of 5.1 years. The comet has extremely low activity for its size and is probably in the process of evolving into an extinct comet.
72P/Denning–Fujikawa is a periodic comet discovered on 4 October 1881 by William Frederick Denning. The comet was not seen at another apparition until recovered by Shigehisa Fujikawa in 1978. From 29 December 1978 until 17 June 2014, the comet was lost. On 17 June 2014 the comet was recovered by Hidetaka Sato at apparent magnitude 16 when it was 50 degrees from the Sun. The comet came to perihelion in June 2023, and will next come to perihelion in May 2032.
Comet 252P/LINEAR is a periodic comet and near-Earth object discovered by the LINEAR survey on April 7, 2000. The comet is a Jupiter family comet, meaning that it passes quite close to the orbit of Jupiter.
300P/Catalina is a periodic, near-Earth comet in the Solar System with an orbital period of 4.4 years. It is the second comet ever listed on the Sentry Risk Table. At 1.4 kilometers in diameter, it is one of the largest objects ever listed on the Sentry Risk Table.
C/2020 F3 (NEOWISE) or Comet NEOWISE is a long period comet with a near-parabolic orbit discovered on March 27, 2020, by astronomers during the NEOWISE mission of the Wide-field Infrared Survey Explorer (WISE) space telescope. At that time, it was an 18th-magnitude object, located 2 AU away from the Sun and 1.7 AU away from Earth.
