Comet Swift–Tuttle

Swift -Tuttle ( official name 109P/Swift-Tuttle ) is a short- period comet, which was discovered each other on July 16, 1862 by Lewis A. Swift, and on 19 July 1862 by Horace Parnell Tuttle independently.

Orbit

The comet moves in around 133 years on an elliptical orbit between 0.96 ( perihelion ) and 51.23 ( aphelion ) astronomical units around the sun, the orbital eccentricity is 0.963. The orbit is inclined about 67 ° to the ecliptic, as the comet but retrograde ( decreasing) moves around the sun, is given its orbital inclination of 113 °. His Perihelgeschwindigkeit is 153,000 km / h

History

On his return in 1862 the comet approached up to 0.34 AE to the earth. He reached an apparent brightness of up to 2 mag, and his tail has a length of up to 30 °.

A determination of the orbit from the observations of 1862 showed an orbital period of 120 years, so the return of the comet was initially expected for the year 1981. However, the comet could not be found. Assuming that the comet was bowlers of 1737 ( C/1737 N1) an earlier appearance of Swift -Tuttle, the U.S. astronomer Brian Marsden said his return for 1992 forward. In fact it was found Swift -Tuttle on September 26, 1992 by the Japanese amateur astronomer Tsuruhiko Kiuchi again. Since the comet never came closer than 1.16 AE with returns of the earth, he only reached a maximum apparent brightness of 5mag.

The comet Swift -Tuttle, the earth but also very close, even a collision with the Earth can not be ruled out over longer periods of time. In the next expected for the year 2126 return of the comet, but there is no danger, because the comet will approach no closer than about 0.15 AU ( 25 million km).

The Great Comet of 69 BC and 188 AD, described by Chinese astronomers were identified with symptoms of the comet Swift -Tuttle.

Parent body of the Perseids

In 1866, the Italian astronomer Giovanni Schiaparelli saw that same orbit of the comet Swift -Tuttle and the derived for the meteoroids in the Perseid meteor stream the tracks. For the first time a mother body of a meteor stream are identified: The comet loses in each cycle of matter. Every year when the Earth around August 12 around crosses the orbit of the comet Swift -Tuttle, reach comet particles at high velocity into the atmosphere and light as meteors on.