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Lost Comet
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. 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. Overview Loss 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 resu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
5D/Brorsen
5D/Brorsen (also known as Brorsen's Comet or Comet 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. Observational history The comet was discovered on February 26, 1846, by Danish astronomer Theodor Brorsen. The perihelion of 5D/Brorsen was February 25, just a day before its discovery, and it passed closest to Earth on March 27, at a distance of . As a result of this close encounter to Earth, the comet's coma diameter increased. Johann Friedrich Julius Schmidt estimated it as 3 to 4 arcminutes across on March 9, and 8 to 10 arcminutes across on the 22nd of that same month. On April 22, it was about 20 degrees from the north celestial pole. By the end of this first apparition the orbital period was calculated as 5.5 years. J. Russell Hind later calculated that this comet had a close approach to Jupiter on 20 May 1842, placing it to the initial orbit f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andromedids
The Andromedids meteor shower is associated with Biela's Comet, the showers occurring as Earth passes through old streams left by the comet's tail. The comet was observed to have broken up by 1846; further drift of the pieces by 1852 suggested the moment of breakup was in either 1842 or early 1843, when the comet was near Jupiter. The breakup led to particularly spectacular showers in subsequent cycles (particularly in 1872 and 1885). In the early 19th century, before the break-up of comet 3D/Biela, the radiant was in Cassiopeia. In the last century the radiant of the modern weaker meteor shower was generally in the constellation of Andromeda as the name of the shower suggests, but due to its age and diffuseness meteors may appear to come from the neighbouring constellations, such as Pisces (near the star Upsilon Piscium), Triangulum and Cassiopeia. Historical appearances The first known sighting of the Andromedids was December 6, 1741, over St Petersburg, Russia. Fur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perturbation (astronomy)
In astronomy, perturbation is the complex motion of a massive body subjected to forces other than the gravitational attraction of a single other massive body. The other forces can include a third (fourth, fifth, etc.) body, resistance, as from an atmosphere, and the off-center attraction of an oblate or otherwise misshapen body. Introduction The study of perturbations began with the first attempts to predict planetary motions in the sky. In ancient times the causes were unknown. Isaac Newton, at the time he formulated his laws of motion and of gravitation, applied them to the first analysis of perturbations, recognizing the complex difficulties of their calculation. Many of the great mathematicians since then have given attention to the various problems involved; throughout the 18th and 19th centuries there was demand for accurate tables of the position of the Moon and planets for marine navigation. The complex motions of gravitational perturbations can be broken down. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
D/1770 L1 (Lexell)
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.Other comets named after their orbit computer, rather than discoverer, are 27P/Crommelin, 2P/Encke and 1P/Halley – Halley's Comet. It is notable for having passed closer to Earth than any other comet in recorded history, approaching to a distance of only ,Kronk, G. Cometography: D/1770 L1 (Lexell)', accessed November 20, 2008.Kronk, G. ', accessed November 20, 20, 2008. It was thought that C/1491 B1 may have approached even closer on February 20, 1491, but its orbit was retracted in 2002 due to a misunderstanding of the records. SeApproximate Orbits of Ancient and Medieval Comets: 3. Remarks and Discussion/ref> or six times the distance from the Earth to the Moon. The comet has not been seen since 1770 and is considered a lost comet. Lexell's Comet's 1770 passing still holds the record of closest observed approach of E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
D/1766 G1 (Helfenzrieder)
Comet Helfenzrieder, also known by its modern designation D/1766 G1, is a Jupiter-family comet that was first seen between April and May 1766. The comet was never recovered on its next apparitions and was subsequently considered lost. Orbit Uncertainties in orbital calculations prevented the comet from being recovered on its next apparitions after 1766. Between 1766 and 1773, Alexandre Guy Pingré made the first parabolic orbits for comet Helfenzrieder, where his computations revealed a perihelion date of 17 April 1766 at a distance of , though he still considered this calculation uncertain. He later revised his calculations in 1784, where he determined that the comet might had reached perihelion on 23 April 1766 at a distance of . Johann Karl Burckhardt was the first astronomer to determine that Helfenzrieder has a short period elliptical orbit in 1821, where he calculated the comet's orbital period to 5.02 years. In 1915, Carl Wilhelm Wirtz noted that three years before ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comet Shoemaker–Levy 9
Comet Shoemaker–Levy 9 ( formally designated D/1993 F2) was a comet that broke apart in July 1992 and collided with Jupiter in July 1994, providing the first direct observation of an extraterrestrial collision of Solar System objects. This generated a large amount of coverage in the popular media, and the comet was closely observed by astronomers worldwide. The collision provided new information about Jupiter and highlighted its possible role in reducing space debris in the inner Solar System. The comet was discovered by astronomers Carolyn and Eugene M. Shoemaker, and David Levy in 1993. Shoemaker–Levy 9 (SL9) had been captured by Jupiter and was orbiting the planet at the time. It was located on the night of March 24 in a photograph taken with the Schmidt telescope at the Palomar Observatory in California. It was the first active comet observed to be orbiting a planet, and had probably been captured by Jupiter around 20 to 30 years earlier. Calculations showed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naming Of Comets
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. The simplest system names comets after the year in which they were observed (e.g. the Great Comet of 1680). Later a convention arose of using the names of people associated with the discovery (e.g. Comet Hale–Bopp) or the first detailed study (e.g. Halley's Comet) of each comet. During the twentieth century, improvements in technology and dedicated searches led to a massive increase in the number of comet discoveries, which led to the creation of a numeric designation scheme. The original scheme assigned codes in the order that comets passed perihelion (e.g. Comet 1970 II). This scheme operated until 1994, when continued increases in the numbers of comets found each year resulted in the creation of a new scheme. This system, which is still in operation, assigns a code based on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Webb Space Telescope
The James Webb Space Telescope (JWST) is a space telescope designed to conduct infrared astronomy. As the largest telescope in space, it is equipped with high-resolution and high-sensitivity instruments, allowing it to view objects too old, List of the most distant astronomical objects, distant, or faint for the Hubble Space Telescope. This enables investigations across many fields of astronomy and cosmology, such as observation of the Population III star, first stars and the Galaxy formation and evolution, formation of the first galaxies, and detailed atmospheric characterization of potentially habitable exoplanets. Although the Webb's mirror diameter is 2.7 times larger than that of the Hubble Space Telescope, it produces images of comparable optical resolution, resolution because it observes in the longer-wavelength infrared spectrum. The longer the wavelength of the spectrum, the larger the information-gathering surface required (mirrors in the infrared spectrum or antenna a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comet Hale–Bopp
Comet Hale–Bopp (formally designated C/1995 O1) 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. Alan Hale (astronomer), Alan Hale and Thomas Bopp discovered Comet Hale–Bopp separately on July 23, 1995, before it became visible to the naked eye. It is difficult to predict the maximum brightness of new comets with any degree of certainty, but Hale–Bopp exceeded most predictions when it passed perihelion on April 1, 1997, reaching about magnitude −1.8. Its massive nucleus size made it visible to the naked eye for a record 18 months. This is twice as long as the Great Comet of 1811, the previous record holder. Accordingly, Hale–Bopp was dubbed the Great Comet of 1997. Discovery The comet was discovered independently on July 23, 1995, by two observers, Alan Hale (astronomer), Alan Hale and Thomas Bopp, both in the United States. Hale had spent many hundreds of hours sear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edward Emerson Barnard
Edward Emerson Barnard (December 16, 1857 – February 6, 1923) was an American astronomer. He was commonly known as E. E. Barnard, and was recognized as a gifted observational astronomer. He is best known for his discovery of the high proper motion of Barnard's Star in 1916, which is named in his honor. Early life Barnard was born in Nashville, Tennessee, on December 16, 1857, to Reuben Barnard and Elizabeth Jane Barnard (''née'' Haywood), and had one brother. His father died three months before his birth, so he grew up in an impoverished family and did not receive much in the way of formal education. His first interest was in the field of photography, and he became a photographer's assistant at the age of nine. He later developed an interest in astronomy. In 1876 he purchased a refractor telescope, and in 1881 he discovered his first comet, but failed to announce his discovery. He found his second comet later the same year and a third in 1882. While he was still working a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
177P/Barnard
Comet 177P/Barnard, also known as Barnard 2, is a periodic comet with an orbital period of 122 years. It fits the classical definition of a Halley-type comet with (20 years < < 200 years). It orbits near the plane and has near the at . The comet, also designated P/2006 M3, was discovered by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
