C / 770 K1

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C / 770 K1 [i]
Properties of the orbit ( animation )
Epoch:  June 9th 770 ( JD 2,002,456.3)
Orbit type parabolic
Numerical eccentricity 1.0
Perihelion 0.58 ± 0.10 AU
Inclination of the orbit plane 117 ± 2 °
Perihelion June 5, 770 ± 1 day
Orbital velocity in the perihelion 55 km / s
history
Explorer
Date of discovery May 25, 770
Older name 770
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . Please also note the note on comet articles .

C / 770 K1 is a comet that could be seen with the naked eye in 770 . It is counted among the " Great Comets " due to its extraordinary brightness .

Discovery and observation

The Chinese chronicles Jiù Táng Shū and Táng Huì Yào from the 10th century , as well as Xīn Táng Shū from the 11th century report that a "broom star" was seen in the north for the first time on May 26th 770 (local time), which probably took place Sighting in the morning sky . The comet appeared as a white object (indicating its brightness) with a tail about 30 degrees long.

On June 19, the "broom star" is said to have been seen again in the morning, it moved eastward in the sky and was seen again on July 9 during an evening observation. All three texts agree that the comet was finally observed for the last time on July 25th, probably on the evening of that day.

A Korean chronicle in Samguk Sagi mentions the sighting of a "broom star" on the morning of July 9th (local time) and a Japanese text from the 18th century also reports the appearance of a "broom star" sometime between the end of June and the end of August.

Pingré mentions two comets in his cometography , one in May and a second in June / July, presumably he did not yet know the Korean and Japanese reports about them. Even Williams called the first Chinese sighting the date 15 June. All of these reports likely refer to the same comet.

The comet reached a brightness of 1 to 2 mag around July 10th .

Orbit

The first calculations of an orbit for this comet were carried out by Hind and Laugier in the mid-19th century . Hasegawa was able to determine a somewhat uncertain parabolic orbit for the comet from 4 observations over 44 days , which is inclined by around 117 ° to the ecliptic . It thus runs in the opposite direction (retrograde) like the planets through its orbit. At the point of the orbit closest to the sun ( perihelion ), which the comet passed through around June 5, 770, it was located at a distance of about 87 million km between the orbits of Mercury and Venus . As early as April 27, he could be in about 110 million km distance on Mars be passed to June 19, he had the Venus km approached to about 92 million, and around the 10th of July, he would be the earth to came close to about 0.30  AU / 44 million km. This close proximity to the earth could have been the reason for its observed brightness. In addition, it may have shown a strong dust tail that would have been seen exactly in side elevation at the time it was passing Earth, which would have been a spectacular sight.

Due to the uncertain initial data, no statement can be made as to whether and, if so, when the comet could return to the inner solar system .

See also

Individual evidence

  1. ^ GW Kronk: Cometography - A Catalog of Comets, Volume 1, Ancient - 1799. Cambridge University Press, Cambridge 1999, ISBN 978-0-521-58504-0 , pp. 119-120.
  2. ^ AG Pingré: Cométographie ou Traité historique et théorique des comètes. Tome I. Imprimerie Royale, Paris 1783, pp. 611-612 ( PDF; 56.49 MB ).
  3. ↑ J. Williams: Observations of Comets, from BC 611 to AD 1640. Strangeways and Walden, London 1871, p. 45 ( PDF, 20.93 MB ).
  4. ↑ DK Yeomans: NASA JPL Solar System Dynamics: Great Comets in History. Retrieved July 5, 2016 .
  5. ^ JR Hind: Elements of several ancient comets. In: Astronomical News. Vol. 21, No. 498, 1844, pp. 279-282.
  6. ^ PAE Laugier: Mémoire sur quelques comètes anciennes. In: Comptes rendus hebdomadaires des séances de l'Académie des sciences. Tome 22. Bachelier, Paris 1846, pp. 148–156.
  7. ^ I. Hasegawa: Orbits of Ancient and Medieval Comets. In: Publications of the Astronomical Society of Japan. Vol. 31, 1979, pp. 257-270 ( bibcode : 1979PASJ ... 31..257H ).
  8. ↑ C / 770 K1 in the Small-Body Database of the Jet Propulsion Laboratory (English).
  9. ↑ A. Vitagliano: SOLEX 11.0. Archived from the original on September 18, 2015 ; accessed on May 2, 2014 .
  10. ^ DAJ Seargent: The Greatest Comets in History: Broom Stars and Celestial Scimitars. Springer, New York 2009, ISBN 978-0-387-09512-7 , pp. 84-85.