This illustration shows one possible path that the comet Kushida-Muramatsu took around Jupiter (located at centre of axes) (Illustration: Ohtsuka/Asher)
The planet Jupiter seems to be as promiscuous as its Olympian namesake. New calculations reveal that in the middle of the last century it had a fling with a wayward comet, which for 12 years joined the gas giant’s harem of moons. The finding helps to explain how comets move from the outer solar system into inner, sometimes Earth-threatening orbits.
Comet Kushida-Muramatsu is the fifth object known to have been captured by Jupiter as a temporary moon. The most famous of these brief companions, Shoemaker-Levy 9, crashed into the planet in 1994.
Astronomers Katsuhiko Ohtsuka of the Tokyo Meteor Network, Japan, and David Asher of Armagh Observatory in Northern Ireland used observations from the discovery of Kushida-Muramatsu in 1993 and its return in 2001 to calculate its orbit over the previous century.
Their model shows that the comet entered Jupiter’s neighbourhood from the outer solar system in 1949 and dallied in a highly irregular orbit, coming perilously close to the planet’s surface three times before being thrown into the inner solar system around 1962.
Uncertainty in the observations makes the comet’s path impossible to determine exactly….
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