Comet Encke
Comet Encke, 2P/Encke, is a small comet with the shortest known orbit of any bright comet, about 3.3 years.
Comet 2P/Encke orbits the Sun every 3.3 years, travelling from inside Mercury's orbit out to the asteroid belt. It was first seen in 1786, but its orbit was worked out in 1819 by the German astronomer Johann Franz Encke, making it only the second periodic comet identified, after Halley's.
Encke's nucleus is about 4.8 kilometres across. It is the parent of the Taurid meteor showers in autumn and the daytime Beta Taurids in June and July. Its orbit is unusual for a comet, lying well inside Jupiter's, and it may have been moved there over many thousands of years by gravitational encounters and the push of its own gas jets.
In 2007, NASA's STEREO spacecraft watched part of Encke's tail being torn off by a burst of the solar wind, a spectacular sight. Encke shows that comets can survive many trips around the Sun while slowly shedding the dust that becomes meteors.
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