C / 1882 R1 (Great September Comet)

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C / 1882 R1 (Great September Comet) [i]
The comet of 1882 on November 7th
The comet of 1882 on November 7th
Properties of the orbit ( animation )
Period:  October 2, 1882 ( JD 2,408,720.5)
Orbit type long-period
Numerical eccentricity 0.999907
Perihelion 0.007751 AU
Aphelion 166.7 AU
Major semi-axis 83.3 AU
Sidereal period ~ 759 a
Inclination of the orbit plane 142.0 °
Perihelion September 17, 1882
Orbital velocity in the perihelion 478 km / s
history
Explorer
Date of discovery September 1, 1882
Older name 1882 II, 1882b
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . Please also note the note on comet articles .

C / 1882 R1 (Great September Comet ) was a comet that could be seen with the naked eye during the day in 1882 . It was probably one of the brightest comets that has ever been observed and is counted among the " Great Comets " due to its extraordinary brightness .

Discovery and observation

Unfortunately, there are no first-hand reports of the earliest observations of this comet. Johann Gottfried Galle later reported that the comet was first seen on the morning of September 1, 1882 in the Gulf of Guinea and the Cape of Good Hope . A day later he was seen in Auckland , three days later in Córdoba (Argentina) and again a day later by a ship in Panama .

The first astronomer to discover the comet through personal observation was William Henry Finlay on September 8 at the Cape of Good Hope. He was on his way home from the Royal Observatory at the Cape of Good Hope and saw the conspicuous comet, which already had a tail 1 ° long. He immediately returned to the observatory to take measurements. Further independent discoveries were made by John Tebbutt in Windsor, New South Wales and Luiz Cruls in Rio de Janeiro on the following days. On September 9, the comet was reported to have a magnitude of 3 to 4 mag and a tail length of 2.5 degrees.

In the days that followed, the comet moved steadily towards the sun , but it did not disappear in the increasing light of dawn , but remained visible. On September 13, the comet's core was already very bright and the straight tail 12 ° long. On September 16, the comet could be observed all day through a finderscope. The brightness increased even further and became so large that the comet could be seen in the bright sky next to the sun. One only had to look in the direction of the sun to see the comet immediately. Several observers in England , Spain , South Africa and Argentina followed the approach of the comet to the sun on September 17th, and it was itself observed through damping filters.

On September 17, the core of the comet finally went from the earth as seen from about 15:35 UT for about 75 minutes before the sun passed. Finlay and William Lewis Elkin watched this event from the Cape of Good Hope. Finlay noted that "the comet's silvery light contrasted sharply with the sun's red and yellow". Elkin reported that at 3:37 pm he saw it "disappear into the undulations of the sun's edge". Finlay lost visual contact 8.5 seconds later, "when the edge of the sun boiled all around him". He thought he saw him again 3 seconds later, but wasn't sure. Then he searched the solar disk very carefully, but could not find the slightest trace of the comet. From purely geometric comparisons and by using the sun as a comparison star, one can estimate the brightness of the comet during the transit to be −12.5 mag.

After the transit, the comet reappeared on the other side of the solar disk around the time of its closest approach to the sun. It moved a little further away from the sun and then moved towards it again, so that it then went back through behind the sun for about 2 hours at around 7:05 p.m. UT. It was observed, however, only about 4½ hours after the end of the eclipse, when Tebbutt found it less than 1 ° from the edge of the sun in broad daylight. The tail appeared ½ ° long. On September 18 and 19, the comet was still observed by numerous observers in the daytime sky, and on September 22 it could be seen up to a quarter of an hour after sunrise. The tail appeared at dawn, 12 degrees long.

After the perihelion, the comet's brightness decreased again, at the beginning of October 1 mag was observed, the length of the tail remained at 15 to 20 ° until October. Towards the end of September, the comet's core was observed to appear elongated towards the tail. On October 3rd, two kernels could finally be found, both of which were elliptically deformed, "like two grains of rice, point to point". By October 18, up to six individual kernels could be observed with increasing clarity, which "appeared like very small pearls strung on a wool thread".

A large number of spectroscopic examinations were carried out on the comet in September and October . In November David Gill was able to take a number of spectacular photographs of the comet. This was only the third time after C / 1858 L1 (Donati) and C / 1881 K1 (Great Comet) that a comet had been photographed. The brightness was still 3.5 mag in mid-November after these recordings. At the beginning of December the brightness had dropped to 5 mag, but the tail was still 15 ° long. The comet remained visible to the naked eye until February 1883, when the tail length was 4 to 6 °. At the beginning of March the tail had disappeared and the last observation was made by John Macon Thome on June 1st, when the comet was already low on the western horizon at nightfall.

The comet reached a magnitude of −4 mag. During the transit across the Sun, the brightness exceeded −10 mag.

Effects on the zeitgeist

The comet was such a striking object that it was noticed and watched by many people around the world.

In October 1882, many provinces of Venice were devastated by floods. Giovanni Schiaparelli , the Italian astronomer, gave a public lecture on the Great Comet of 1882 in Milan on February 4, 1883 , in which he declared the popular view of a connection between the two events to be very unlikely - on the one hand because of the great ones Distance of the comet to the earth and to the other because of the difficulty in understanding why the comet should only have affected this very small part of the world.

Scientific evaluation

Comets that pass as close to the Sun as the Great Comet of 1882 have puzzled astronomers for over 300 years. Since it was proven that the Great Comet C / 1680 V1 from 1680 had almost grazed the sun's surface at a distance of only 200,000 km, they wondered, on the one hand, how comets can survive something like this, and on the other hand, when such a sun streamer had before could have appeared.

The Great March Comet C / 1843 D1 appeared in 1843 as the first bright sun-grazing comet of the 19th century . For a long time three or four comets from the last third of the 17th century (not the comet of 1680) were considered to be its previous appearances . Values ​​of 175 years down to the completely impossible 7 years have been assumed as the orbital period of the comet. Direct calculations based on the observations of the comet showed, however, that the orbital period probably cannot be shorter than 400 to 500 years.

When the Great Southern Comet C / 1880 C1 appeared in 1880 , orbiting in almost the same orbit, the proponents of a 35- to 40-year period had a great time again. When the Great September Comet C / 1882 R1 reappeared with a very similar orbit in 1882, it was already assumed that this sun streak would have been slowed down very strongly at each return by friction in a solid medium surrounding the sun. However, this turned out to be incorrect, as the observation data of the comet from 1882 showed an orbital period of several centuries.

The conclusion was that there must be a number of different comets moving in practically the same sun-grazing orbit. Daniel Kirkwood was the first to suggest in 1880 that the sun-grazing comets formed such a comet group. He suggested that the comets of 1843 and 1880 could be fragments of the comet of −371 , which, according to the report of the Greek historian Ephoros, had broken in two. The comet of 1882 also broke into several fragments as it passed the sun. A few years later, another member of this comet group was identified with the great southern comet C / 1887 B1 .

The sun streaker was then examined very intensively from 1888 to 1901 by Heinrich Kreutz , who suspected that all members of the comet group later named after him, the Kreutz group , descended from an original body that broke when it passed the sun. He identified other possible members of the group, and further group members appeared in the 20th century in 1945, 1963, 1965 and 1970.

In 1967 Brian Marsden examined the orbits of the previously known comets of the Kreutz group and showed that their members can be divided into two subgroups. The comet C / 1882 R1 is therefore the most important representative of subgroup II. From the similarity of the orbital elements with the comet C / 1965 S1 (Ikeya-Seki) , he deduced as well as proven that both comets were on their last passage were still a body of the sun in the first half of the 12th century . Whether this could have been the well-known comet X / 1106 C1 , however, could not be proven. As a result, there were many attempts to theoretically capture the possible processes of decay and the resulting trajectories of the sun stripes, in particular by Zdenek Sekanina and others.

In 2002 Sekanina and Paul W. Chodas examined the possible decay process of the comet of 1106 in more detail. By comparing the orbital elements of the two sun stripes from 1882 and 1965, they were able to confirm Marsden's assumption that they have a common origin and that they must have divided about 18 days after the perihelion of their original comet, when it was already 0.75 AU from the sun was removed.

In further very extensive investigations, Sekanina & Chodas developed new theories about the origin and development of the Kreutz comet group, which currently reflect the current state of knowledge. According to the model of the two super fragments, it can be assumed that all the sun streakers of the Kreutz group descend from a very large predecessor comet with a diameter of almost 100 km, which may have been in the late 4th century or early 5th century a few decades before it passed the sun has broken in two roughly equal parts. The two super fragments made one more orbit around the sun and super fragment I reappeared in 1106 as the famous sun streaker X / 1106 C1. Superfragment II appeared only a few years earlier or later, but apparently escaped observation due to unfavorable viewing conditions as there are no reports about it. Both super fragments broke into further fragments shortly after their extremely close passage to the sun at the time, internally damaged by the enormous tidal forces ( cascading fragmentation ): Superfragment II disintegrated into at least three other parts, the largest reappeared later as comet C / 1882 R1, the other parts were (partly after further decay processes) the source of further sun-grazing comets that appeared in 1945, 1963, 1965 and 1970. The comet from -371, however, as it turned out, had no relation to the Kreutz group.

For the size of comet C / 1882 R1, in 2002 Sekanina estimated a diameter of ~ 50 km from comparisons with the brightness of other comets, a more recent work by Matthew M. Knight et al. Names a diameter of ~ 30 km and a mass of 42 × 10 15 kg.

Orbit

Numerous astronomers calculated more or less precise orbital elements for the comet. Heinrich Kreutz was finally able to calculate orbits for the four brightest fragments A – D of the comet in 1891 , which resulted in orbits between 772 and 995 years. In 1919 Leon Hufnagel calculated even better orbital elements for the brightest and apparently largest fragment B from 1,500 observation data over a period of 260 days. He also took relativistic effects into account in his calculation and wanted to derive further evidence for the correctness of Albert Einstein's then new general theory of relativity , which he did not succeed in doing. The path elements calculated by Hufnagel for fragment B are given in the info box.

The following information is based on the orbital elements for the comet's center of mass, which were assumed by Sekanina & Chodas in 2002 based on theoretical considerations about the orbit before and after the comet's core decay and using modern mathematical methods, taking into account all planetary disturbances and relativistic effects. According to this, the comet described an extremely elongated elliptical orbit before its decay , which was inclined at around 142 ° to the ecliptic . The comet thus ran in the opposite sense (retrograde) like the planets through its orbit. The value for the semi-major axis was 86.4 AU and the eccentricity 0.999910. At the point of the orbit closest to the sun ( perihelion ), which the comet traversed on September 17, 1882, it was only ⅔ of a solar radius above its surface at about 1.16 million km from the sun . Only 75 minutes earlier it had come within 107.6 million km of Venus , while about 15 hours earlier it had already come closest to the earth at 0.98 AU / 146.2 million km.

According to recent studies, the comet is likely a fragment of an unobserved comet that appeared in the first years of the 12th century , after which its orbital period to its last passage through the inner solar system would have been about 780 years. For the four larger fragments A – D, into which the comet had disintegrated shortly after its perihelion passage, Sekanina & Chodas were able to calculate orbital elements corresponding to approximate orbital times of 659 (A), 760 (B), 863 (C) and 943 years (D) run out. However, since it can be assumed that the fragments will continue to decay during their current orbit around the sun, around the calculated dates of their return 2487 (A), 2571 (B), 2656 (C) and 2719 (D) each small groups of Comets appear.

See also

Web links

Individual evidence

  1. ↑ a b SOLEX 11.0 by A. Vitagliano. Archived from the original on September 18, 2015 ; accessed on May 2, 2014 .
  2. ↑ JM Pasachoff, RJM Olson, ML Hazen: The earliest comet photographs: Usherwood, Bond, and Donati 1858. In: Journal for the History of Astronomy. XXVII, 1996, pp. 129-145 ( bibcode : 1996JHA .... 27..129P ).
  3. ^ GW Kronk: Cometography - A Catalog of Comets. Volume 2: 1800-1899. Cambridge University Press, 2003, ISBN 0-521-58505-8 , pp. 503-516.
  4. ^ DAJ Seargent: The Greatest Comets in History: Broom Stars and Celestial Scimitars. Springer, New York 2009, ISBN 978-0-387-09512-7 , pp. 211-219.
  5. ^ P. Moore, R. Rees: Patrick Moore's Data Book of Astronomy. Cambridge University Press, Cambridge 2011, ISBN 978-0-521-89935-2 , p. 270.
  6. ^ Francis Porro: Professor Schiaparelli on the Great Comet of 1882. In: Nature. Vol. 27, 1883, pp. 533-534 doi: 10.1038 / 027533a0 .
  7. ^ Daniel Kirkwood: On the Great Southern Comet of 1880. In: The Observatory. Vol. 3, No. 43, 1880, pp. 590-592 ( bibcode : 1880Obs ..... 3..590K ).
  8. ↑ BG Marsden: The Sungrazing Comet Group. In: The Astronomical Journal. Vol. 72, No. 9, 1967, pp. 1170-1183 ( bibcode : 1967AJ ..... 72.1170M ).
  9. ^ Zdeněk Sekanina: Problems of origin and evolution of the Kreutz family of Sun-grazing comets. In: Acta Universitatis Carolinae. Mathematica et Physica. Vol. 8, No. 2, 1967, pp. 33-84 ( PDF; 4.73 MB ).
  10. ↑ a b Zdenek Sekanina, Paul W. Chodas: Common Origin of Two Major Sungrazing Comets. In: The Astrophysical Journal. Vol. 581, 2002, pp. 760-769 doi: 10.1086 / 344216 .
  11. ↑ Zdenek Sekanina, Paul W. Chodas: Fragmentation Hierarchy of Bright Sungrazing Comets and the Birth and Orbital Evolution of the Kreutz System. I. Two-Superfragment Model. In: The Astrophysical Journal. Vol. 607, 2004, pp. 620-639 doi: 10.1086 / 383466 .
  12. ↑ a b Zdenek Sekanina, Paul W. Chodas: Fragmentation Hierarchy of Bright Sungrazing Comets and the Birth and Orbital Evolution of the Kreutz System. II. The Case for Cascading Fragmentation. In: The Astrophysical Journal. Vol. 663, 2007, pp. 657-676 doi: 10.1086 / 517490 .
  13. ^ Zdenek Sekanina: Statistical Investigation and Modeling of Sungrazing Comets discovered with the Solar and Heliospheric Observatory. In: The Astrophysical Journal. Vol. 566, 2002, pp. 577-598 doi: 10.1086 / 324335 .
  14. ↑ MM Knight, MF A'Hearn, DA Biesecker, G. Faury, DP Hamilton, P. Lamy, A. Llebaria: Photometric Study of the Kreutz Comets Observed by SOHO from 1996 to 2005. In: The Astronomical Journal. Vol. 139, 2010, pp. 926-949 doi: 10.1088 / 0004-6256 / 139/3/926 .
  15. ^ Leon Hufnagel: The orbit of the September comet 1882 II based on Einstein's theory of gravitation. In: Astronomical News. Volume 209, No. 4994, 1919, Col. 17-22 doi: 10.1002 / asna.19192090202 .
  16. ↑ C / 1882 R1 (Great September Comet) in the Small-Body Database of the Jet Propulsion Laboratory (English).