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C/1861 J1 (Large Comet)

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C/1861 J1 (Great Comet)[ i ]
Künstlerische Darstellung des Kometen
Artistic representation of the comet
Properties of the orbit (animation)

Epoch: May 25, 1861 (JD 2,400,920.5)
Orbit type long-period
Numerical eccentricity 0,9851
Perihelion 0.822 AE
Aphelion 109.3 AU
Large semi-axis 55.1 AU
Sidereal period ~409 a
Inclination of the orbital plane 85,4°
Perihelion 12. June 1861
Orbital velocity at perihelion 46.3 km/s
History
Discoverer John Tebbutt
Discovery date 13. May 1861
Older designation 1861 II
Source: Unless individually noted otherwise, data are from JPL Small-Body Database Browser. Please also note the reference to comet articles.

C/1861 J1 (Great Comet) (also called Comet Tebbutt ) was a comet that could be seen with the naked eye in the summer of 1861. Because of its extraordinary brightness and imposing tail, it is among the most spectacular of the Great Comets.

Discovery and observation

On the evening of May 13, 1861, farmer and amateur astronomer John Tebbutt was searching the western sky for comets with a small telescope in Windsor (New South Wales), Australia when he noticed a faint nebulous object whose brightness he estimated to be about 5 mag. His star catalogues did not record a nebula at that location and he suspected it was a comet, so he decided to continue observing it over the next few nights. However, it initially showed no noticeable proper motion on the evening of May 14, so he already doubted that it was a comet. It was not until May 21, eight days after his discovery, that he was able to observe the object again, and now for the first time he was able to detect motion in front of the stellar background and sent a report to William Scott of the Sydney Observatory and to the Sydney Morning Herald, which reported it on May 25.[1] Scott was able to observe the comet on 22 May, and on 27 May the latter succeeded for the first time in sighting the comet with the naked eye.

At the time of its discovery, the comet was still 0.99 AU from the Sun and 1.27 AU from Earth, and it continued to approach both in early June. On June 3, the comet was seen at dawn in Cape Town with a brightness of 2-3 mag and with a 3° tail pointing south. By 8 June it was already clearly visible to the naked eye, the tail length having grown to 18°. Only four days later it was already 40°. A week later the tail was already “longer than that of any other comet seen in the [southern] hemisphere since the memorable one of 1843,” as a Herald correspondent wrote on June 19. On June 20, it could be seen that the comet’s tail had split into two parts, a longer one 40° long and a shorter one 5° long, which were widely separated.

After initially being observable only from the southern hemisphere, the comet had moved rapidly northward and by late June was visible in the northern hemisphere – as news of Tebbutt’s discovery had not yet reached there in part, surprising many observers. On June 30, when the comet reached its closest proximity to Earth, it was observable before sunset, and the brightness emanating from the tail during the night was so strong that it cast shadows on a white wall, as reported by Johann Friedrich Julius Schmidt in Athens. The brightness of the nucleus of the comet was thereby between that of Venus and Jupiter. The coma had a diameter of 1° and the tail was very impressive with a number of rays. Its length was estimated by different observers to be between 30 and 120°. The unusual surface brightness of the tail was caused by forward scattering of sunlight by dust particles in the coma, since the comet was between the Sun and Earth and its tail was almost pointing toward Earth. It may even have passed through part of the dust tail, as there were many conspicuous luminosities in the atmosphere in those days, as reported by John Russell Hind in England as well as Tebbutt in Australia. Telescopic observations of the comet’s nucleus also showed strange effects such as light veils and rays.

Drawing of the comet’s head on June 30

After this great spectacle at the beginning of July the brightness of the comet decreased noticeably again. While at first brightnesses around 1 mag and tail lengths of 45 to 100° were still observed, on July 5 there were reports of 85° length of the main tail and 30° length of the secondary tail. David Livingstone could observe the comet on July 6 during his trip on the river Shire in Malawi.

On July 8, the secondary tail appeared to have disappeared, while the main tail was still estimated to be 15-60° long with detectable streaks. The light veils in the coma had also disappeared. As the distance from the Sun and Earth increased, the brightness of the comet decreased rapidly. On July 12 it was still 3 mag with 20 to 30° tail length and in the middle of August 5 mag with 2.5° tail length. The last observation with the naked eye took place on 15 August by Eduard Heis. Telescopic observations could still be continued until 30 April of the following year by Friedrich August Theodor Winnecke and Otto Wilhelm von Struve in Russia, when the brightness of the comet dropped below 14 mag.[2][3][4]

The comet reached a brightness of 0 mag on 27 June 1861.[5] According to other data the brightness reached even -2 mag.[6]

Effects on the zeitgeist

Tebbutt had seen from his observations that the comet was moving approximately towards the Earth. He was able to calculate a “rough approximate orbit” of the comet, which was published in the Sydney Morning Herald, as well as predicting that the comet would approach Earth around June 29 and that it would pass within a short distance of the comet’s tail. Tebbutt also suggested that the comet might become visible in the daytime sky around that time. However, these predictions apparently caused no consternation among readers, in stark contrast to the effect of similar predictions 50 years later when the Earth passed through the tail of Halley’s comet on its return.

The comet caused a great public sensation worldwide, and it was widely reported in newspapers. Its appearance coincided with the outbreak of the American Civil War, which is why it was known in the United States as the great war com et. There were a number of cartoons to mark the occasion in which the comet was depicted with the head of various contemporary politicians or military leaders, such as Abraham Lincoln or General Winfield Scott.[7] In the satirical magazine Punch appeared a cartoon showing dinosaurs watching the comet and recognizing in it an old acquaintance.[8]

Four crew members of the Peruvian had survived the shipwreck off the Queensland coast in 1846. One of them, James Morrill, subsequently lived among the Aborigines for 17 years. In his memoirs, published in 1864, he recalls seeing a comet. This may have been the comet Tebbutt. The Aborigines told him that the comet was the spirit of one of their tribesmen who had been killed in a distant war and was coming home from the clouds to the horizon.[9]

Scientific evaluation

J. F. J. Schmidt, by evaluating the observations of the tail length and coma diameter of the comet, was able to establish a synchronous periodicity of both of about 25.5 days and suggested that both were influenced by the same factor.

After the first calculation of a parabolic orbit by Tebbutt shortly after the discovery, numerous other attempts to determine the orbital elements of the comet were made soon after as more observational data became available, including by Maurice Loewy, John Russell Hind, Asaph Hall, and Horace Parnell Tuttle. These each determined parabolic orbits, and in one case a hyperbolic orbit. In September 1861, the true orbit of the comet was first determined to be elliptical by Arthur von Auwers. When the comet had already disappeared again, orbital elements could be calculated that covered the entire period of its visibility. In 1880 Heinrich Kreutz determined orbital parameters of the comet which indicate an orbital period of about 409 years.[3] The comet thus has the shortest orbital period of all great comets after Halley’s Comet.

Kreutz calculated these values before the advent of modern computers and computational methods and was only able to account for the major perturbations of four planets. R. L. Branham calculated more accurate orbital elements for the comet in 2013 using 2362 observation dates between May 1861 and March 1862 and taking into account the perturbations of all planets and other mathematical methods.[10]

Orbit

For the comet, Kreutz was able to calculate an elliptical orbit inclined at about 85° to the ecliptic from 1159 observational data over a period of 339 days.[11] The comet’s orbit is thus almost perpendicular to the orbital planes of the planets. At the closest point to the Sun in its orbit (perihelion), which the comet passed through on 12 June 1861, it was located between the orbits of Venus and Earth at a distance of about 123.0 million km from the Sun. On June 30, it reached its closest approach to Earth at about 19.8 million km (0.13 AU). On July 7 it still approached Mercury up to about 88.2 million km, no significant approaches to the other minor planets took place.

The relatively inaccurate orbital elements given in the JPL Small-Body Database, which do not account for non-gravitational forces on the comet, are still from Kreutz. The same initial data were also used by Marsden, Sekanina, and Everhart in their calculation of the comet’s original and future orbits.[12] According to these, long before its passage of the inner solar system in 1861, its orbit still had an eccentricity of about 0.98374 and a major semimajor axis of about 50.8 AU, so that its orbital period was about 362 years. Thus the previous perihelion passage could have occurred around the year 1499. From this year there are no reports of a conspicuous comet. From the Far East, however, there are reports of a comet sighting from the year 1500. According to I. Hasegawa and S. Nakano the orbital elements of this comet C/1500 H1, which were derived from 10 observations, could be interpreted in such a way that it could have been the same comet as the one of 1861, the orbital period would have been about 361 years before the last perihelion passage.[13]

Due to the gravitational pull of the planets, especially relatively close passes of Saturn around 31 January 1858 at a distance of about 3 ¾ AU and of Jupiter around 5 January 1860 at a distance of about 1 ¾ AU, based on Kreutzʼ orbital calculation its orbital eccentricity would have been increased to about 0.98491 and its major semimajor axis to about 54.8 AU, increasing its orbital period to about 406 years. The next perihelion passage of the comet would therefore take place around the year 2267.

The improved determination of the orbit by R. L. Branham differs slightly but significantly from Kreutzʼ orbital elements,[10] in particular, according to Branham, the comet’s orbit would originally have had an eccentricity of about 0.98256 and a major semimajor axis of about 47.4 AU, so that its orbital period would have been about 326 years and the previous perihelion transit would have occurred around the middle of the year 1535 (uncertainty ±4 months). Branham nevertheless does not rule out a connection with the comet of 1500.a The future orbit of the comet would have an eccentricity of about 0.98373 and a major semi-axis of about 50.9 AU, so that its orbital period would be about 363 years. Accordingly, when the celestial body reaches the farthest point (aphelion) from the Sun in its orbit around the year 2042, it will be about 15.1 billion km from the Sun, nearly 101 times as far as Earth and 3 ⅓ times as far as Neptune. Its orbital velocity at aphelion will then be only about 0.37 km/s. The next perihelion transit of the comet would possibly take place in the second half of 2223 (uncertainty ±5 months).[14]

a However, this is not easily possible with the purely gravitational orbital elements and their tolerances given by him, cf. the previous sentence regarding orbital period. It might be possible if non-gravitational forces on the comet were taken into account.

Reception in literature

The comet was treated in detail in a separate chapter of the work L’espace céleste et la nature tropicale by Emmanuel Liais.[15]

In the chronicle of the Franciscan monastery of Reutte the comet was described as follows:

“About this time there was also to be seen a magnificent comet-star, which, though somewhat smaller in its rays than that of 1859,b but was nevertheless of considerable size – its extent was 20 degrees.”[16]

b Misspelling or transmission error, only comet C/1858 L1 (Donati) can be meant.

See also

  • List of comets
  • Large Comet

Web links

Commons: Great Comet of 1861– Collection of images, videos and audio files

Individual references

  1. N. Lomb:The discovery of the Great Comet of 1861 by John Tebbutt.Retrieved September 9, 2014 (English).
  2. D. A. J. Seargent: The Greatest Comets in History: Broom Stars and Celestial Scimitars. Springer, New York 2009, ISBN 978-0-387-09512-7, pp. 136-142.
  3. a b G. W. Kronk: Cometography – A Catalog of Comets, Volume 2. 1800-1899. Cambridge University Press, Cambridge 2003, ISBN 0-521-58505-8, pp. 293-302.
  4. P. Grego: Blazing a Ghostly Trail: ISON and Great Comets of the Past and Future. Springer, Cham 2013, ISBN 978-3-319-01774-7, pp. 116-117.
  5. D. K. Yeomans:NASA JPL Solar System Dynamics: Great Comets in History.Retrieved 17 June 2014 (English).
  6. P. Moore, R. Rees: Patrick Moore’s Data Book of Astronomy. Cambridge University Press, Cambridge 2011, ISBN 978-0-521-89935-2, p. 270.
  7. Americas studies blog – The Great Comet of 1861 and the Civil War.British Library, retrieved 9 September 2014 (English).
  8. 1861 Punch Dinosaurs & Comet Cartoon.pixels, retrieved 8 September 2020 (English).
  9. D. W. Hamacher, R. P. Norris: Comets in Australian Aboriginal Astronomy. In: Journal for Astronomical History & Heritage. Vol. 14, No. 1, 2011, pp. 31-40(PDF; 623 kB)
  10. a b R. L. Branham, Jr: A New Orbit for Comet C/1861 J1 (Great Comet of 1861). In: Revista Mexicana de Astronomía y Astrofísica. Vol. 50, 2014, pp. 109-118.(PDF; 408 kB) Note: The osculating elements given there in Table 6 are incorrect with respect to i and ω. The values in Table 4 should be used instead.
  11. C/1861 J1 (large comet) in the Jet Propulsion Laboratory Small-Body Database (English).Template:JPL Small-Body Database Browser/Maintenance/Old
  12. B. G. Marsden, Z. Sekanina, E. Everhart: New osculating orbits for 110 comets and analysis of original orbits for 200 comets. In: The Astronomical Journal. Vol. 83, No. 1, 1978, pp. 64-71 doi:10.1086/112177.(PDF; 890 kB)
  13. I. Hasegawa, S. Nakano: Periodic Comets Found in Historical Records. In: Publications of the Astronomical Society of Japan. Vol. 47, No. 5, 1995, pp. 699-671 bibcode:1995PASJ…47..699H.(PDF; 331 kB)
  14. A. Vitagliano:SOLEX 12.1.Retrieved July 9, 2020 (English).
  15. E. Liais: L’espace céleste et la nature tropicale: description physique de l’univers, d’après des observations personnelles faites dans les deux hémisphères. Garnier Frères, Paris 1865, pp. 296-314(PDF; 1.9 MB)
  16. P. M. Hollaus: Himmlische Schreckensboten – Beschreibung besonderer Himmelserscheinungen in Chroniken der Tiroler Franziskanerprovinz. In: Austria franciscana. No. 8, 2011, pp. 91-97.(PDF; 485 kB)