C / 1844 Y1 (Great Comet)

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C / 1844 Y1 (Great Comet) [i]
Properties of the orbit ( animation )
Epoch:  December 20, 1844 ( JD 2,394,920.5)
Orbit type long-period
Numerical eccentricity 0.99930
Perihelion 0.250 AU
Aphelion 717.6 AU
Major semi-axis 358.9 AU
Sidereal period ~ 6800  a
Inclination of the orbit plane 45.6 °
Perihelion December 14, 1844
Orbital velocity in the perihelion 84.1 km / s
history
Explorer
Date of discovery December 16, 1844
Older name 1844 III
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . Please also note the note on comet articles .

C / 1844 Y1 (Great Comet) is a comet that could be seen with the naked eye in the southern hemisphere at the turn of the year 1844/45 . Due to its brightness, it is counted among the " Great Comets ".

Discovery and observation

There are only second-hand reports of the discovery of this comet, so the actual discoverer is not known. François Arago reported in March 1845 in the Comptes rendus de l'Académie des sciences that the comet was observed for the first time in Guyana at dusk on December 16, 1844 . He did not provide any further information.

In the following days there were several independent discoveries in the southern hemisphere, for example on December 18 in Cape Town ( South Africa ) and on December 19 in New South Wales ( Australia ). Also on December 19, there was another independent discovery by E. Wilmot at the Cape of Good Hope , who was the first to officially announce its discovery, which is why the comet is sometimes referred to as "Comet Wilmot". His discovery was immediately confirmed by observations made by Thomas Maclear at the Royal Observatory . At that time the comet already had a 3–4 ° long tail. Other independent discoveries were made on December 20th from a ship and in New Zealand , and on December 22nd in New Zealand.

At this time the comet had already passed through its perihelion , but since it was getting closer to the earth , it did not appear weaker at first and could be seen better and better at dusk. There have been numerous observations in the South Atlantic , South Africa, Guyana, India and Ceylon . By the end of the year the tail reached a length of 15 °, it was slightly curved and had sharply defined edges. At the beginning of January 1845 the core was reported to have a brightness of up to 2.5 mag, most observers spoke of 5–6 mag. In mid-January, the tail length and brightness decreased again and the comet could no longer be observed well in the following days because of the full moon . At the beginning of February, the comet's brightness continued to decrease so that it could no longer be observed with the naked eye. It was around this time that it first became visible to observers in the northern hemisphere with telescopes , where it was first observed in Italy on February 5 .

On January 21st, the comet had passed the comet C / 1844 N1 (Mauvais) , discovered in July 1844, at a small angular distance of about 4 ° for observers on Earth , both could be seen on February 7th by observers in Italy and on February 9th be observed by an observer in South Africa together with comet seekers . At the beginning of March the comet was difficult to observe and the last observation was made on March 12, 1845.

According to Hermann Mucke, the comet achieved a total brightness of –1 mag.

Effects on the zeitgeist

There are no reports from the Aborigines about this comet from Australia , but the discoverer Ludwig Leichhardt saw a comet on his first expedition on December 29, 1844 in central Queensland , which is why he called the river he was currently on Comet Creek ( today: Comet River ). Today's Comet was named after the Cometville River when it was later founded .

In New Zealand, too, the comet drew the interest of many residents to astronomy, which was very favorable at a time when the first European astronomers came to Wellington .

Scientific evaluation

Just a few days after the discovery of comet C / 2019 Y4 (ATLAS) by the Asteroid Terrestrial-Impact Last Alert System (ATLAS) on Mauna Loa on December 28, 2019, the amateur astronomer M. Meyer noted that the orbital elements of the comet bear a striking resemblance to those of comet C / 1844 Y1. It was then assumed that both comets have a common origin, i.e. that they could be fragments of a larger comet that broke when it had passed the sun earlier .

In a study by M. Hui and Q. Ye, in which they report on the observation results of comet C / 2019 Y4 (ATLAS), they also found that this comet, which dissolved near the Sun in 2020, was about 5000 years ago, when it last passed the sun, it had undergone a process of decay, during which it separated from the larger fragment, which later appeared as comet C / 1844 Y1. The two fragments moved away from each other at a speed of at least 1 m / s, which meant that they only reached their next perihelion at a distance of 175.5 years.

In their investigation, they also gave purely gravitational orbit parameters for comet C / 1844 Y1, for which they used 70 observation data over a period of 78 days. With these data, they were able to show that the fission process between comets C / 1844 Y1 and C / 2019 Y4 (ATLAS) is no further in the past than during their (common) last perihelion, which they date around the year −2900.

Orbit

For the comet in 1850 was from the observational data by George Phillips Bond a hyperbolic calculated orbit. More recently, an elongated elliptical orbit could be determined from 41 observation data over a period of 72 days by Marsden , Sekanina and Everhart , which is inclined by around 46 ° to the ecliptic . The comet's orbit is thus inclined to the planets of the planets . At the point closest to the Sun (perihelion), which the comet passed on December 14, 1844, it was about 37.5 million km from the Sun and was within the range of Mercury's orbit . On September 9th, he had passed Mars approximately 121.5 million km . On November 26th it passed Venus at a distance of about 99.4 million km and on December 17th it passed Mercury at a distance of about 22.8 million km. On January 6, 1845, it reached the closest approximation to the earth with about 142.9 million km (0.96  AU ).

Marsden, Sekanina and Everhart have already given values ​​for the original and the future semiaxis of the comet's orbit. According to the orbit elements derived from them, which, however, did not take into account non-gravitational forces on the comet, its orbit still had an eccentricity of about 0.99935 and a semi-major axis of about 386 AU long before it passed through the inner solar system , so that its orbit period was about 7590 years. Due to the gravitational pull of the planets, especially due to the relatively close passages of Saturn on December 16, 1844 at a distance of about 9 ¾ AU, as well as at Jupiter on January 13, 1845 in about 4 ½ AU and again on August 22, 1846 in about 5 ¼ AU distance, however, its orbital eccentricity was reduced to about 0.99899 and its semi-major axis to about 245 AU, so that its orbital period was shortened to about 3840 years.

If comet C / 1844 Y1 has a common origin with comet C / 2019 Y4 (ATLAS), as indicated by the almost identical orbital parameters, it would have had an orbital period of about 4800 years before it passed through the inner solar system (corresponding to a large Semiaxis of the orbit of about 285 AU), since the two bodies probably separated during their last passage in the sun about 5000 years ago. The reason for the deviation from the above-mentioned data is probably the lack of consideration of non-gravitational forces in the determination of the orbit parameters by Marsden, Sekanina and Everhart. The parameters could nowadays be derived more precisely taking into account the orbit of comet C / 2019 Y4 (ATLAS), whereby the future orbit of comet C / 1844 Y1 could also be predicted more precisely.

See also

Individual evidence

  1. ^ GW Kronk: Cometography - A Catalog of Comets. Volume 2: 1800-1899 . Cambridge University Press, 2003, ISBN 0-521-58505-8 , pp. 145-149.
  2. ^ J. Sauval: Longest Visibility of Ancient Comets. ESO, May 21, 1997, accessed July 14, 2020 .
  3. ^ DW Hamacher, RP Norris: Comets in Australian Aboriginal Astronomy. In: Journal for Astronomical History & Heritage. Volume 14, No. 1, 2011, pp. 31-40 arXiv: 1010.0801 . ( bibcode : 2011JAHH ... 14 ... 31H ).
  4. ↑ W. Orchiston: Great Comets, and Wellington's Earliest European Astronomers. In: Exploring the History of New Zealand Astronomy. Astrophysics and Space Science Library, Volume 422, Cham 2016, ISBN 978-3-319-22565-4 , pp. 566-573 doi: 10.1007 / 978-3-319-22566-1_20 .
  5. ↑ M. Meyer: A10j7UG. In: Comets Mailing List. Groups.io, December 31, 2019, accessed August 5, 2020 .
  6. ↑ Man-To Hui (許文韜), Quan-Zhi Ye (葉 泉 志): Observations of Disintegrating Long-period Comet C / 2019 Y4 (ATLAS): A Sibling of C / 1844 Y1 (Great Comet). In: The Astronomical Journal. Volume 160, No. 2, 2020, pp. 1–16 doi: 10.3847 / 1538-3881 / ab9d81 .
  7. ^ GP Bond: On the Great Comet of 1844-45. In: The Astronomical Journal. Vol. 1, No. 13, 1850, pp. 97-103 doi: 10.1086 / 100067 ( bibcode : 1850AJ ...... 1 ... 97B ). ( PDF; 849 kB )
  8. ^ BG Marsden, Z. Sekanina, E. Everhart: New Osculating Orbits for 110 Comets and Analysis of Original Orbits for 200 Comets. In: The Astronomical Journal. Volume 83, No. 1, 1978, pp. 64-71 doi: 10.1086 / 112177 ( bibcode : 1978AJ ..... 83 ... 64M ). ( PDF; 900 kB )
  9. ↑ C / 1844 Y1 (Great Comet) in the Small-Body Database of the Jet Propulsion Laboratory (English).Template: JPL Small-Body Database Browser / Maintenance / Alt
  10. ↑ A. Vitagliano: SOLEX 12.1. Retrieved July 9, 2020 .