12P/Pons–Brooks

12P/Pons–Brooks

Discovery
Discovered by	Jean-Louis Pons William Robert Brooks
Discovery date	July 12, 1812
Alternative designations	1812; 1884 I; 1954 VII
Orbital characteristics ^A
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] 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 new religions around the world^[3] 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.^[4] The Jet Propulsion Laboratory's (JPL) website shows that between the years 1900 and 2200, that the comet is only insignificantly perturbed by Saturn on July 29, 1957, when it passes within 1.6AU of the giant planet's powerful influence.^[5]

References

1. "12P/Pons-Brooks". JPL Small-Body Database. Jet Propulsion Laboratory. SPK-ID: 1000068. Retrieved 2011-10-17.
2. 12P/Pons-Brooks – Seiichi Yoshida @ aerith.net
3. Graham Phillips: The End of Eden
4. Kronk, Gary W. (2001–2005). "12P/Pons-Brooks". Archived from the original on 2009-05-09. Retrieved 2009-05-07. (Cometography Home Page)
5. "12P/Pons-Brooks close-approach data". JPL Small-Body Database. Jet Propulsion Laboratory. SPK-ID: 1000068. Retrieved 2009-05-06.

External links

• 12P/Pons-Brooks at the JPL Small-Body Database

• Discovery · Orbit diagram · Orbital elements · Physical parameters

• Comet 12P/Pons-Brooks light curve (Dmitry Chestnov)