12P/Pons–Brooks

12P/Pons–Brooks

Discovery
Discovered by:	Jean-Louis Pons William Robert Brooks
Discovery date:	July 12, 1812
Alternate designations:	1812; 1884 I; 1954 VII
Orbital characteristics A
Epoch:	1954-Sep-15[1]
Aphelion distance:	33.468 AU
Perihelion distance:	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 January 25, 1884 September 15, 1812
Next perihelion:	April 21, 2024[2]

12P/Pons–Brooks is a periodic comet with a period of 71 years. The comet was suggested by Carl Sagan 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 monotheistic religions around the world^{[citation needed]}. Fragments of the comet may have barely missed Earth in 1883. It will next appear in 2024.^[2]

Discovery

12P/Pons–Brooks was discovered on July 12, 1812 by Jean-Louis Pons. Independently, it was later found by Vincent Wisniewski on August 1, and Alexis Bouvard on August 2 the same year. In 1883 it was accidentally "discovered" by William Robert Brooks and later identified as the same object. 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.

Orbit

With a steep orbital inclination of 74.2° this comet does not spend a lot of time near the ecliptic where it is easiest to interact with other bodies. The comet's orbit appears to be stable between 1740 and 2167, with no strong perturbations by any of the planets.^[3] The Jet Propulsion Laboratory's (JPL) website shows that between the years 1900 and 2200, that the comet is only noticeably perturbed by Saturn on July 29, 1957, when it passes within 1.6AU of the giant planet's powerful influence.^[4]

Bonilla's comet

Mexican astronomers have suggested that a comet may have split into several pieces around 1883 and that Earth barely avoided multiple Tunguska events or even a mass extinction.^[5] On August 12-13th of 1883, Mexican astronomer José Bonilla observed 447 bodies cross the solar disc.^[5] These objects were estimated to have had a size of between 46 and 1022 meters,^[5] and to have passed only 538 to 8062 km from the Earth.^[5] But the source of these objects could also have been an unknown comet or comet C/1883 D1 (Brooks-Swift).^[5] The event also coincided with the annual Perseids meteor shower. Even migrating birds can not be ruled out.^[5]

References

1. ^ "JPL Small-Body Database Browser: 12P/Pons-Brooks". Jet Propulsion Laboratory. 1954-08-23 last obs. http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=12P. Retrieved 2011-10-17. 
2. ^ ^{a b} 12P/Pons-Brooks – Seiichi Yoshida @ aerith.net
3. ^ Kronk, Gary W. (2001–2005). "12P/Pons-Brooks". Archived from the original on 2009-05-09. http://cometography.com/pcomets/012p.html. Retrieved 2009-05-07.  (Cometography Home Page)
4. ^ "JPL Close-Approach Data: 12P/Pons-Brooks". 1954-08-23 last obs. http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=12P;cad=1#cad. Retrieved 2009-05-06. 
5. ^ ^{a b c d e f} Manterola, Hector Javier Durand; Maria de la Paz Ramos Lara, Guadalupe Cordero (2011). "Interpretation of the observations made in 1883 in Zacatecas (Mexico): A fragmented Comet that nearly hits the Earth". arXiv. arXiv:1110.2798. 

External links

• Orbital simulation from JPL (Java) / Ephemeris
• Comet 12P/Pons-Brooks light curve (Dmitry Chestnov)

Periodic comets (by number)
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