What are large comets?
Large comets are those that become particularly bright and
The firstOne of the criteria necessary for a comet to be classified as large is its orbit. The comet must pass by the Sun or the Earth.
Secondly, a large comet must have a large core; the larger the core, the better.
Thirdly, visibility:comets that pass close to Earth could potentially be bright, but only visible for a couple of days. A comet farther from Earth will linger longer in the sky and provide sufficient time for continuous observation.
And finally,fourthlyfor a comet to be called big, it must have a dusty tail. An abundance of dust is a prerequisite for a large visible tail and an inherent feature of large comets.
Great Comet C/1811 F1 (Great Comet)
The comet was first discovered on March 25, 1811Honore Flaugergom at a distance of 2.7 AU. e. from the Sun. It was noticed by many in Marseille with the naked eye. In April, the comet's discovery was officially confirmed.
Observations of the comet continued until mid-June.when the comet disappeared in the rays of the Sun, after which it became visible from Earth only in August. On September 12, the comet reached its minimum distance from the Sun (1.04 AU). William Herschel, who observed the comet, estimated the size of its nucleus at 689 km. On October 16, 1811, the distance of the comet from the Earth reached a minimum (1.22 AU), and four days later the greatest brightness of the comet was recorded, becoming comparable in brightness to the most prominent stars in the night sky. In December 1811, the comet's tail bent away from the nucleus by 70°. It was very impressive, although it did not come close to either the Earth or the Sun. In Cuba, the comet was visible to the naked eye until January 9, 1812, that is, only more than 9 months, before the appearance of the famous Comet Hale-Bopp, this was a record.
Drawing by astronomer William Henry Smith
The last observation of this comet dates back to August 17, 1812, on that day VK Vishnevsky was able to distinguish it in the form of a barely noticeable speck of 12th magnitude with a telescope in Novocherkassk.
When she returns?
The comet's orbital period around the Sun is defined as 3100 years. Therefore, the next comet return is expected at the end of the fifth millennium.
Comet Donati (C / 1858 L1, 1858 VI)
Comet Donati is a long-period comet,discovered by the Italian astronomer Giovanni Donati on June 2, 1858. After the Big Comet of 1811, it was the most beautiful comet to appear in the 19th century. The previous large comet was observed in 1854. She was also the first comet photographed.
Author: E. Weiß — E. Weiß: Bilderatlas der Sternenwet,Public Domain
Comet Donati is described by 19th century astronomers as the most beautiful comet ever seen. She has appeared in many works of art. It is worth noting that it became the first comet photographed.
Photo of comet Donati. The Royal Observatory, Edinburgh
Perihelion - its closest approach to the Sun - it passed on September 30, at which time its tail reached 40° in length and 10° in width. The closest it came to Earth was on October 10, 1858.
It is said that even Abraham Lincoln sat at his window and watched her. It was a very dusty comet with an arched tail about 50 ° long.
When she returns?
The return of comet C / 1858 L1 is expected in the XXXIX century - about 3811.
Great comet of 1882 (C / 1882 R1)
The Great September Comet of 1882 is the brightestthe comet of the 19th century and one of the brightest in the last millennium, due to which it received the name "Big Comet". It was independently discovered by several people at once. When it appeared in early September of that year, it was easily visible in the predawn hours, even without special equipment. The comet was rapidly gaining brightness, approaching the Sun.
On September 17, the comet reached perihelion and stellarmagnitude –17.0, flying just 480 thousand km from the surface of the Sun - and was visible in broad daylight. On September 30, the coma area looked elongated, and two fragments were already visible. By October 17, their number increased to five.
Photo of a comet taken
By David Gill in Cape Town
Even though her core has undergoneWith such a strong decay at perihelion, the comet remained visible until June 1, 1883. The subsequent destruction of the core in the post-perihelion resulted in the appearance of a large amount of dust, making the tail even more visible.
The Great September Comet became one of the most famous members of the Kreutz family of comets - a group of fragments formed after the collapse of one large comet several hundred years ago.
When she returns?
The comet's orbital period is about 800 years.
Big Januarycomet 1910year, orDay comet (C/1910 A1)
The Great January Comet of 1910, or Daycomet (English Daylight comet, that is, visible in daylight), the official designation C / 1910 A1 - a bright comet that appeared in January 1910. It surpassed Venus in brightness.
The comet reached perihelion on January 17 and was visible in broad daylight with a magnitude of –5.0.
After perihelion, its value sharply decreased byas he moved to the skies of the Northern Hemisphere. But the magnificent tail of dust compensated for the darkening, and by early February it stretched out to 50 °. Under normal circumstances, this object would not be a large comet: its absolute magnitude was insufficient, and its distance from Earth was not too close.
However, its close passage of perihelion and dust-rich composition changed the situation.
When she returns?
This comet's long orbital period means it will return in about 57,000 years.
Comet Ikei - Seki (C / 1965 S1)
Comet Ikeya - Seki, C / 1965 S1 (Ikeya - Seki) -a long-period comet, which was independently discovered by Japanese observers Kaoru Ikeya and Tsutomu Seki. It was first observed on September 18, 1965 as a faint telescopic object. The first calculations of its orbit showed that on October 21, it will pass at a distance of only about 450 thousand km above the surface of the Sun and, possibly, become extremely bright.
Image of the National Optical Astronomy Observatory
Expectations met:As the comet approached perihelion, observers reported that it was clearly visible in the daytime sky near the Sun. In Japan, the comet passed perihelion at noon local time and was 60 times brighter than the full moon.Comet Ikei - SekiIt turned out to be one of the brightest comets of the last millennium, and therefore is sometimes called the “Great Comet of 1965.”
Shortly before the passage of perihelion, a cometsplit into three parts. The three fragments continued to move in nearly identical orbits, and the comet was again visible in the morning sky at the end of October, showing a very bright tail. In early 1966, the comet was no longer visible as it was heading into the outer solar system.
Comet Ikei - Sekibelongs to the Kreutz family of circumsolar comets.
When she returns?
The time of its next perihelion is unknown, it is now heading towards the outer part of the Solar System. Fragment periods may return in 800-1000 years.
Comet BennettC / 1969 Y1)
Comet C / 1969 Y1 (Bennett)- one of two bright comets observedwith the naked eye in the 1970s (along with Comet Vesta). Due to its brightness, it is one of the great comets. It became the second comet in the history of astronomy observed from artificial Earth satellites.
Due to the convenient relative position of the cometand the Earth (elongation is more than 32 ° all the time), it was continuously observed from the moment of discovery in the southern sky until mid-September 1970 near the north pole of the sky. From 391 observations over a period of about 10 months, Marsden was able to determine an elliptical orbit for the comet, which is tilted to the ecliptic by about 90 °, so that its orbit is perpendicular to the orbits of the planets. At the orbital point closest to the Sun (perihelion), which the comet last passed on March 20, 1970, it was slightly farther from the Sun than the innermost planet Mercury, at a distance of about 80.4 million km. On March 26, it approached the Earth to 0.69 AU. e. / 103.0 million km.
When she returns?
The next perihelion is expected in 3600.
Comet Hyakutake (C / 1996 B2)
Comet Hyakutake (C / 1996 B2 (Hyakutake)), flew near Earth in 1996.
Comet C / 1996 B2 (Hyakutake), also known asA large comet of 1996, was discovered on January 30, 1996 by the Japanese amateur astronomer Yuji Hyakutake. The comet passed at a distance of 0.1 AU. from Earth on March 25, 1996.
Author: E. Kolmhofer, H. Raab; Johannes-Kepler-Observatory, Linz, Austria (http://www.sternwarte.at) — Own work, CC BY-SA 3.0
Comet Hyakutake is a long-period comet.This means that the comet has undergone few flights to the Sun and retained its core in its original form. After passing the perihelion in 1996, the comet's orbit has undergone strong disturbances from the planets of the solar system.
When she returns?
According to the HORIZONS ephemeris generator, the next time comet Hyakutake will pass perihelion in more than 108 thousand years.
Comet Hale-Bopp (C/1995 O1)
Comet Hale - Bopp (C / 1995 O1) -a long-period comet, which has become, perhaps, the most "observed" comet of the 20th century, and one of the brightest in the past few decades. A record period of 18 months was visible to the naked eye, twice the previous record set by the Great Comet in 1811.
Opened July 23, 1995 at a very largedistance from the Sun (about 7.2 AU), suggesting that it will be quite bright when approaching the Earth. Despite the difficulty of predicting the brightness of comets to any degree of accuracy, this comet met and exceeded the expectations of astronomers, having passed the perihelion on April 1, 1997. It is sometimes called the "Big Comet of 1997".
The appearance of Comet Hale-Bopp also causedconfusion among the people, which has not been observed for a long time. Rumors have been widely publicized that an alien ship is flying after the comet. The same rumors became the impetus for mass suicide among the followers of the new religious movement "Gates of Paradise".
When she returns?
The comet's next perihelion is expected in 4380.
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Astronomical unit - historicallya unit of measurement for distances in astronomy. Initially, it was taken to be equal to the semi-major axis of the Earth's orbit, which in astronomy is considered the average distance from the Earth to the Sun: 126.
Coma - a cloud of dust and gas that surrounds the corecomets. Together, the "coma" and "nucleus" form the "head" of the comet. As the comet approaches the Sun, the "head" increases, and sometimes a "tail" appears. The comet's coma has an almost spherical shape and usually stretches from 100 thousand to 1.4 million km from the nucleus.
Near-solar comets Kreutz - familycircumsolar comets, named after the astronomer Heinrich Kreutz, who first showed their relationship. It is believed that they are all parts of one large comet that collapsed several centuries ago.