Comets short period

Short-period comets these display a strong tendency for their farthest point from the sun (aphelia) to coincide with a giant planet s orbital radius, so that we can distinguish so-called comet families . The Jupiter family of comets is the largest and numbers around 70 comets. The shortest orbital period known is that of the short-period comet Encke—about 3.3 years. 

Short-period comets are thought to have originated in the Kuiper belt (Luu and Jewitt, 1996). 

Kuiper Belt a region in the outer Solar System beyond Neptune s orbit populated by small icy planetesimals or Kuiper Belt objects, and dwarf planets. Many short-period comets (possessing orbits of less than 200 years) are thrown into the Solar System from the Kuiper Belt. 

Water abundances for 7 comets for which O and OH abundances are now available are given in Table 1. The comets with eccentricities near 1 which have probably been on one of their first close perihelion passages (Kohoutek is the only new comet in this list) have much larger H O productions than the short periodic comets Encke and Bradfield (periods 3.3 years and 250 years resp.). This result agrees with the icy conglomerate model. 

Duncan M., Quinn T., and Tremaine S. (1988) The origin of short-period comets. Astrophys. J. 328, L69-L73. 

Levison H. F. and Duncan M. J. (1994) The long-term dynamical behavior of short-period comets. Icarus 108, 18-36. 

S4 [90,91] (Table 16.2). A typical comet composition is based on the relative amounts of the different gas species measured in the coma of comets from the Oort cloud, an immense spherical cloud surrounding the solar system and extending from approximately 5000 to 100,000 AU. About half of the short-period comets arc from the Kuiper Belt, a disk-shaped region containing many small icy bodies extending beyond Neptune s orbit from 30 to 50 AU, which are depleted in carbon-chain molecules. The other short-period comets have the typical composition of Oort cloud comets. So far, carbyne molecules detected in the coma of active comets are very short chains unlike the longer chains characteristic of natural carbyne crystals such as chaoite in the Murchison meteorite [20,67]. 

Halley s comet A bright comet with a period of 75-76 years, its last visit to the inner solar system was in i986. This comet was the first short-period comet to be recognized, its orbit was first calculated in i705 by Edmund Haliey, after whom it is named. The comet moves around the sun in the opposite direction to the planets and is associated with two meteor showers, the EtaAquarids (May) and the Orionids (October). 

Goesmann, E, Rosenbauer, H., Roll, R., Bohnhardt, H. (2005) COSAC onboard Rosetta a bioastronomy experiment for the short-period comet 67P/Churyumov-Gerasimenko. Astrobiology, 5(5), 622-631. DOI 10.1089/ ast.2005.5.622... 

Short period comets their orbital periods about the Sun are less than 200 years. At aphelion (when their distance from the Sun is at maximum) they are at distances of Jupiter and beyond. The aphelion of comet Halley is about the orbit of Neptune. Comets of the Jupiter family have orbital periods of less than 20 years. The existence of such families of comets can be attributed to the gravitational influence of Jupiter. ... 

The icy objects in the Kuiper belt and Oort cloud become ejected into the inner solar system where they appear as comets. Perturbations by outer planets occur in the Kuiper belt, these become short period comets, perturbations by nearby passing stars affect objects in the Oort cloud, these become long period comets. 

Comet Tempel 1 was discovered in 1867 by E. Tempel. At the time of discovery, the comet was 0.7 AU from the Earth and 1.6 AU from the Sun. Currently, Tempel 1 has an orbital period of 5.5 years and a perihelion distance of roughly 1.5 AU. With an orbital eccentricity of 0.5, Tempel 1 s orbit lies between the orbits of Mars and Jupiter. These values varied in the past and will change in the future because of close approaches with the planet Jupiter. It therefore belongs to the group of short period comets. 

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