Another Neptun Trojan discovered
Scott Sheppard of the Carnegie Institute and Chadwick Trujillo of the Gemini Observatory have found a fourth Trojan asteroid orbiting Neptune. Only four of these objects are known for the planet. Scientists have now been able to identify over 2000 around Jupiter.
Trojans are chunks of rock and ice less than 300 kilometers across, similar in composition to asteroids from other populations such as the Kuiper Belt Objects. They orbit the sun in the same orbit as their planet, but about sixty degrees behind or ahead of it. At these libration points, the ones from the planet and the sun on the smaller body cancel each other out and so to speak fix it in this position.
While the German astronomer Max Wolf discovered Jupiter's first Trojan as early as 1906, it took considerably longer for Neptune to detect the chunks, which were difficult to track down given the distance: the first of these was only identified in 2001, and in 2004 and In 2005, Sheppard and Trojillo delivered the next.
The last of the bunch has an oddly tilted orbit compared to the others, supporting the suggestion that Neptune, like Jupiter, is surrounded by a veritable cloud of these objects. Also, because Neptune's four companions are all the same color-a pale red-the researchers believe they share a common origin.
