Authors: Harold F. Levison, Eugene M. Shoemaker & Carolyn S. Shoemaker

Status: 1997. Nature, 385, 42-44

Abstract: Trojan asteroids are objects that orbit the Sun with the same mean semi-major axis as Jupiter, but lead or trail the position of Jupiter in its orbit by ~60 degrees. One very interesting aspect of the Trojan swarms is that a significant number of asteroids are on orbits that analytic theory suggests should be unstable. This has lead several researchers to conclude that there is a flaw in the analytic theory. Here we present the results of the first long-term dynamical integrations of the orbits of Trojan asteroids. We find that the Trojan swarms are indeed not indefinitely stable. The gravitational effects of the giant planets have whittled away the swarms' outer boundary over time. We estimate that there are currently over 200 escaped Trojans larger than 1 km in diameter currently roaming the solar system, a few of which are on Earth-crossing orbits.

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