12P/Pons–Brooks
| Discovery | |
|---|---|
| Discovered by | Jean-Louis Pons William Robert Brooks |
| Discovery date | July 12, 1812 |
| Designations | |
| 1812; 1884 I; 1954 VII | |
| Orbital characteristics | |
| Epoch | 1954-Sep-15[1] |
| Aphelion | 33.468 AU |
| Perihelion | 0.77366 AU |
| Semi-major axis | 17.1212 AU |
| Eccentricity | 0.95481 |
| Orbital period | 70.85 yr |
| Inclination | 74.176° |
| Last perihelion | May 22, 1954[2] January 25, 1884 September 15, 1812 |
| Next perihelion | April 21, 2024[2] |
12P/Pons–Brooks is a periodic comet with an orbital period of 71 years. It fits the classical definition of a Halley-type comet with (20 years < period < 200 years).[1] Its next closest approach to Earth is in 2024.[2]
As of December 2015 12P/Pons–Brooks has not been identified with any meteor-shower clouds.[3]
Discovery
A comet was observed from Korea from 10 April to June 1313 CE.[4] Over in China, "in the reign of Jin Tsung, the 2nd year of the epoch Hwang King, 3rd moon, day Ting Wei, a comet appeared in the eastern part of S. D. Tsing". This date is calculated to 13 April 1313; the eastern part of the "S. D. Tsing" corresponds to the stars Mebsuta, Alhena, and Propus in Gemini: about right-ascension 6h and declination 20°.[5]
Koreans observed "another" comet over 20 March - 22 May 1668.[6] This one started from Pisces (~RA 1h, Dec. 30°) and traveled southwest across Cetus toward Eridanus (~RA 5h, Dec. -10°.). (Interestingly a comet was also recorded beginning early March 1668 by Europeans, but poorly; this appeared in the "Whale" constellation today known as Cetus and likewise traveled to Eridanus.[7][8]) In the West a third observation was logged on July 12, 1812, by Jean-Louis Pons. Independently, this comet was later found by Vincent Wisniewski on August 1, and Alexis Bouvard on August 2 the same year. At the time no-one had brought these three observations together.
In 1883 a "fourth" comet was accidentally discovered by William Robert Brooks and later identified as the same object as the 1812. Shortly after its initial discovery it was found to have an orbital period of about 70 years with an error of about 5 years. Johann Franz Encke determined a definitive orbit with a period of 70.68 years. This orbit was used to generate an ephemeris for the 1883 return, but searches were unsuccessful, until it was rediscovered by Brooks. In 2007, Korean astronomers So-Yeon Park and Jongchul Chae identified Pons-Brooks with the observations of 1313 and of 1668.[9]
Orbit
Libration is locked at a 6:1 resonance with Jupiter.[10] The Tisserand invariant with respect to Jupiter (J) is 0.60.[11]
With a steep orbital inclination of 74.2° this comet does not spend a lot of time near the ecliptic. The Jet Propulsion Laboratory's (JPL) website shows that between the years 1900 and 2200, that the comet was and will be most significantly perturbed by Saturn on July 29, 1957. At that point it passed within 1.6AU of the giant planet's influence; even this approach had negligible effect.[13] The comet's orbit appears to be stable between 1740 and 2167, with no strong perturbations by any of the planets.[14][15]
Prehistorical speculation
Carl Sagan suggested 12P as the spectacular comet seen by the Chinese in 1486 BCE which, according to historical researcher Graham Phillips, might have inspired the rise of a number of new religions around the world[16]
References
- ^ a b "12P/Pons-Brooks". JPL Small-Body Database. Jet Propulsion Laboratory. SPK-ID: 1000068. Retrieved 2011-10-17.
- ^ a b c 12P/Pons-Brooks – Seiichi Yoshida @ aerith.net
- ^ Dušan Tomko (1 December 2015). "Modeling of a theoretical stream of comet 12P/Pons-Brooks". Planetary and Space Science. 118: 35–37.
- ^ So-Yeon Park; Jongchul Chae (2007). "Analysis of Korean Historical Comet Records". Publications of the Korean Astronomical Society. 22: 151–68.
{{cite journal}}: CS1 maint: multiple names: authors list (link), 163-4 #4.3.2, fig. 18. - ^ John Williams (1871). Observations of Comets from B. C. 611 to A. D. 1640: Extracted from the Chinese Annals. Translated, with introductury Remarks, and Appendix, comprising the Tables necessary for reducing Chinese Time to European reckoning and Chinese celestial Atlas. Strangways and Walden., 68 #284. This takes Yuan-era events from "the supplement to [Ma Twan Lin's encyclopaedia] and the She Ke".
- ^ So-Yeon Park and Jongchul Chae, fig. 17.
- ^ P. Valentin Estancel (1674). "Observations Concerning the Comet That Was Seen in Brasil, An. 1668 in March". Phil. Trans. 9: 91–93.
- ^ Lynn, W. T. (1882). "The Comet of 1668". The Observatory. 5: 329–331.
- ^ So-Yeon Park and Jongchul Chae.
- ^ A. Carusi, L. Kresak, E. Perozzi, G.B. Valsecchi (1987). "High-order librations of Halley-type comets". Astronomy and Astrophysics. 187: 899–905.
{{cite journal}}: CS1 maint: multiple names: authors list (link), 900. - ^ Ibidem, 899.
- ^ A. Carusi, L. Kresak, E. Perozzi, G.B. Valsecchi. Fig. 5. Text, 902; graph, 903a
- ^ "12P/Pons-Brooks close-approach data". JPL Small-Body Database. Jet Propulsion Laboratory. SPK-ID: 1000068. Retrieved 2009-05-06.
- ^
Kronk, Gary W. (2001–2005). "12P/Pons-Brooks". Archived from the original on 2009-05-09. Retrieved 2009-05-07.
{{cite web}}: Unknown parameter|deadurl=ignored (|url-status=suggested) (help) (Cometography Home Page) - ^ A. Carusi, L. Kresak, E. Perozzi, G.B. Valsecchi, 905.
- ^ Graham Phillips: The End of Eden
External links
- 12P/Pons-Brooks at the JPL Small-Body Database
- Comet 12P/Pons-Brooks light curve (Dmitry Chestnov)
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