166P/NEAT

166P/NEAT is a periodic comet and centaur in the outer Solar System. It was discovered by the Near Earth Asteroid Tracking (NEAT) project in 2001 and initially classified a comet with provisional designation P/2001 T4 (NEAT), as it was apparent from the discovery observations that the body exhibited a cometary coma. It is one of few known bodies with centaur-like orbits that display a coma, along with 60558 Echeclus, 2060 Chiron, 165P/LINEAR and 167P/CINEOS. It is also one of the reddest centaurs.[6]

166P/NEAT has a perihelion distance of 8.56 AU,[1] and is a Chiron-type comet with (TJupiter > 3; a > aJupiter).[1]

166P/NEAT
166PNEAT.tiff
Discovery
Discovered byNEAT
Discovery dateOctober 15, 2001
Alternative
designations
P/2001 T4
Orbital characteristics A
EpochMarch 6, 2006
Aphelion19.1 AU
Perihelion8.559 AU
Semi-major axis13.83 AU
Eccentricity0.3811
Orbital period51.43 a
Inclination15.3813°
Last perihelionMay 20, 2002[1]
Next perihelionNovember 26, 2053[2][3][4][5]

References

  1. ^ a b c "JPL Small-Body Database Browser: 166P/NEAT (2001 T4)" (2008-03-02 last obs). Retrieved 2008-09-14.
  2. ^ "166P/NEAT Orbit". Minor Planet Center. Retrieved 2014-06-18.
  3. ^ Syuichi Nakano (2005-06-30). "166P/NEAT (2001 T4) (NK 1187)". OAA Computing and Minor Planet Sections. Retrieved 2012-02-20.
  4. ^ Seiichi Yoshida (2005-11-09). "166P/NEAT". Seiichi Yoshida's Comet Catalog. Retrieved 2012-02-20.
  5. ^ Horizons output. "Observer Table for Comet 166P/NEAT". Retrieved 2012-02-20. (Observer Location:@sun)
  6. ^ Bauer, James M.; Fernández, Yanga R. & Meech, Karen J. (2003). "An Optical Survey of the Active Centaur C/NEAT (2001 T4)". Publications of the Astronomical Society of the Pacific. 115 (810): 981–989. Bibcode:2003PASP..115..981B. doi:10.1086/377012.

External links

Numbered comets
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165P/LINEAR
166P/NEAT Next
167P/CINEOS
165P/LINEAR

165P/LINEAR is a periodic comet in the Solar System. 165P/LINEAR has a perihelion distance of 6.8 AU, and is a Chiron-type comet with (TJupiter smaller than 3 and a semi-major axis larger than Jupiter's).

166 (number)

166 (one hundred [and] sixty-six) is the natural number following 165 and preceding 167.

167P/CINEOS

167P/CINEOS is a periodic comet in the solar system. It is a Chiron-type comet with (TJupiter > 3; a > aJupiter). It will pass 1.64 AU from Uranus in June 2039.

2060 Chiron

2060 Chiron (), provisional designation 1977 UB, and also known as 95P/Chiron, is a small solar system body (or minor planet) in the outer Solar System, orbiting the Sun between Saturn and Uranus. Discovered in 1977 by Charles Kowal, it was the first-identified member of a new class of objects now known as centaurs—bodies orbiting between the asteroid belt and the Kuiper belt.Although it was initially called an asteroid and classified only as a minor planet with the designation "2060 Chiron", it was later found to exhibit behavior typical of a comet. Today it is classified as both a minor planet and a comet, and is accordingly also known by the cometary designation "95P/Chiron".

Chiron is named after the centaur Chiron in Greek mythology.

Michael Brown lists it as possibly a dwarf planet with a measured diameter of 206 km (128 miles) which is near the lower limit for an icy dwarf planet (around 200 km, or 124 miles).

276P/Vorobjov

276P/Vorobjov (previously P/2012 T7 (VOROBJOV)) is a Jupiter-family comet discovered on 15 October 2012 by Tomáš Vorobjov on three 120-s images taken remotely using the 0.81-m f/7 Ritchey-Chretien Schulman Telescope located at the Mt. Lemmon SkyCenter via the Sierra Stars Observatory Network in the course of a minor-planet search survey undertaken as part of the International Astronomical Search Collaboration (IASC) school campaigns. After posting on the Minor Planet Center's NEOCP webpage, other observers have commented on the object's cometary appearance. The discovery was announced by the Minor Planet Center on 18 October, three days after the discovery.

C/2012 E2 (SWAN)

Comet C/2012 E2 (SWAN) was a Kreutz group sungrazing comet discovered by Vladimir Bezugly in publicly available images taken by the SWAN instrument (Solar Wind ANisotropies) on board the SOHO spacecraft. It is recognized for being the first Kreutz sungrazer observed in SWAN imagery.

C/2015 F3

Comet C/2015 F3 (SWAN) was discovered in March 2015 by Rob Matson, Vladimir Bezugly and Michael Matiazzo in near real time images taken by the SWAN instrument aboard the SOHO spacecraft. At discovery the comet was already shining at around 10th magnitude as it was already near perihelion

. Orbital studies revealed C/2015 F3 to be a related fragment to long periodic comets C/1988 A1 (Liller) and C/1996 Q1 (Tabur), which were already thought to have broken off each other at a previous perihelion passage. As of May 2015, Comet SWAN was fading rapidly, as both C/1988 A1 and C/1996 Q1 ultimately did. .

C/2015 F5 (SWAN-XingMing)

Comet C/2015 F5 (SWAN-XingMing) was discovered on March 29, 2015 in near real time SWAN images of the SOHO spacecraft, by Szymon Liwo and Worachate Boonplod. It was also independently discovered on April 4, 2015 by Guoyou Sun and Gao Xing at the XingMing observatory near Ürümqi, China. At discovery, the comet had just passed perihelion and was only 0,35 AU from the Sun, shining at about +10 mag. As of May 2015 the comet had faded below mag +13. The comet is periodic with an orbital period of about 61 years .

Centaur (minor planet)

Centaurs are small Solar System bodies with a semi-major axis between those of the outer planets. They generally have unstable orbits because they cross or have crossed the orbits of one or more of the giant planets; almost all their orbits have dynamic lifetimes of only a few million years, but there is one centaur, (514107) 2015 BZ509, which may be in a stable (though retrograde) orbit. Centaurs typically behave with characteristics of both asteroids and comets. They are named after the mythological centaurs that were a mixture of horse and human. It has been estimated that there are around 44,000 centaurs in the Solar System with diameters larger than 1 kilometer.The first centaur to be discovered, under the definition of the Jet Propulsion Laboratory and the one used here, was 944 Hidalgo in 1920. However, they were not recognized as a distinct population until the discovery of 2060 Chiron in 1977. The largest confirmed centaur is 10199 Chariklo, which at 260 kilometers in diameter is as big as a mid-sized main-belt asteroid, and is known to have a system of rings. It was discovered in 1997. However, the lost centaur 1995 SN55 may be somewhat larger.

No centaur has been photographed up close, although there is evidence that Saturn's moon Phoebe, imaged by the Cassini probe in 2004, may be a captured centaur that originated in the Kuiper belt. In addition, the Hubble Space Telescope has gleaned some information about the surface features of 8405 Asbolus.

As of 2008, three centaurs have been found to display comet-like comas: 2060 Chiron, 60558 Echeclus, and 166P/NEAT. Chiron and Echeclus are therefore classified as both asteroids and comets. Other centaurs, such as 52872 Okyrhoe, are suspected of having shown comas. Any centaur that is perturbed close enough to the Sun is expected to become a comet.

Comet

A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena are due to the effects of solar radiation and the solar wind acting upon the nucleus of the comet. Comet nuclei range from a few hundred metres to tens of kilometres across and are composed of loose collections of ice, dust, and small rocky particles. The coma may be up to 15 times the Earth's diameter, while the tail may stretch one astronomical unit. If sufficiently bright, a comet may be seen from the Earth without the aid of a telescope and may subtend an arc of 30° (60 Moons) across the sky. Comets have been observed and recorded since ancient times by many cultures.

Comets usually have highly eccentric elliptical orbits, and they have a wide range of orbital periods, ranging from several years to potentially several millions of years. Short-period comets originate in the Kuiper belt or its associated scattered disc, which lie beyond the orbit of Neptune. Long-period comets are thought to originate in the Oort cloud, a spherical cloud of icy bodies extending from outside the Kuiper belt to halfway to the nearest star. Long-period comets are set in motion towards the Sun from the Oort cloud by gravitational perturbations caused by passing stars and the galactic tide. Hyperbolic comets may pass once through the inner Solar System before being flung to interstellar space. The appearance of a comet is called an apparition.

Comets are distinguished from asteroids by the presence of an extended, gravitationally unbound atmosphere surrounding their central nucleus. This atmosphere has parts termed the coma (the central part immediately surrounding the nucleus) and the tail (a typically linear section consisting of dust or gas blown out from the coma by the Sun's light pressure or outstreaming solar wind plasma). However, extinct comets that have passed close to the Sun many times have lost nearly all of their volatile ices and dust and may come to resemble small asteroids. Asteroids are thought to have a different origin from comets, having formed inside the orbit of Jupiter rather than in the outer Solar System. The discovery of main-belt comets and active centaur minor planets has blurred the distinction between asteroids and comets. In the early 21st century, the discovery of some minor bodies with long-period comet orbits, but characteristics of inner solar system asteroids, were called Manx comets. They are still classified as comets, such as C/2014 S3 (PANSTARRS). 27 Manx comets were found from 2013 to 2017.As of July 2018 there are 6,339 known comets, a number that is steadily increasing as they are discovered. However, this represents only a tiny fraction of the total potential comet population, as the reservoir of comet-like bodies in the outer Solar System (in the Oort cloud) is estimated to be one trillion. Roughly one comet per year is visible to the naked eye, though many of those are faint and unspectacular. Particularly bright examples are called "great comets". Comets have been visited by unmanned probes such as the European Space Agency's Rosetta, which became the first ever to land a robotic spacecraft on a comet, and NASA's Deep Impact, which blasted a crater on Comet Tempel 1 to study its interior.

List of numbered comets

This is a list of periodic comets that were numbered by the Minor Planet Center after having been observed on at least two occasions. As of October 2018 there are 375 numbered comets (1P–375P), most of them being members of the Jupiter-family (JFC). There are also 27 Encke-type comets (ETCs), 14 Halley-type comets (HTCs), 4 Chiron-type comets (CTCs), and one long-period comet (i.e. 153P). Many of these bodies are also near-Earth comets (NECs). In addition, 8 numbered comets are principally classified as minor planets – five main-belt comets, two centaurs (CEN), and one Apollo asteroid – and display characteristics of both an asteroid and a comet.

Occasionally, comets will break up into multiple chunks, as volatiles coming off the comet may cause it to break into two or more pieces. An extreme example of this is 73P/Schwassmann–Wachmann, which broke into over 50 pieces during its 1995 perihelion.

For a larger list of periodic Jupiter-family and Halley-type comets including unnumbered bodies, see list of periodic comets.

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