Neptune’s “Trojan” Asteroids

Some asteroids that share the orbit of a larger body, such as a planet, without interfering with it, are known as “Trojans”. Lagrange points are orbital positions found near two objects, that allow a third object to remain in a balanced and stable position. There are two clusters of asteroids that have accumulated near Lagrange points in the orbit of Jupiter, one group that leads Jupiter and one that trails it. These asteroids were given the names of heros from Homer’s epic tale, “The Illiad”. Over time, they have become known as the Trojan asteroids. Some other planets also have asteroids in similar orbits that are also called Trojans.


Trojan (asteroid)
– [daviddarling.info]

Unless qualified, “Trojan” is assumed to mean “Jupiter Trojan.” There are three known Mars Trojans and four known Neptune Trojans but searches have so far failed to uncover any similar objects in the orbits of any of the other planets. Saturn’s satellites Helene, Calypso, and Telesto are also sometimes called Trojans because they lie at the leading Lagrangian point of Dione, and at the trailing and leading Lagrangian points of Tethys, respectively.

Neptune Trojan – [daviddarling.info]

The known Neptune Trojans are estimated to have diameters of 60 to 140 km. From a statistical analysis based on the 25° tilt of 2005 TN53’s orbit, researchers have inferred that Neptune may have between five and 20 times more of these large objects than Jupiter does. Jupiter has only one known Trojan in this upper size range. Based on this difference, astronomers estimate that Neptune’s smaller Trojans also outnumber Jupiter’s. Other research implies that Jupiter may have about the same number of asteroids as the main asteroid belt, so astronomers indirectly conclude that Neptune Trojans may outnumber the tens of thousands of asteroids in the main asteroid belt.

Asteroid found in gravitational ‘dead zone’ – [physorg.com]

There are places in space where the gravitational tug between a planet and the Sun balance out, allowing other smaller bodies to remain stable. These places are called Lagrangian points. So-called Trojan asteroids have been found in some of these stable spots near Jupiter and Neptune. Trojans share their planet’s orbit and help astronomers understand how the planets formed and how the solar system evolved. Now Scott Sheppard at the Carnegie Institution’s Department of Terrestrial Magnetism and Chad Trujillo* have discovered the first Trojan asteroid, 2008 LC18, in a difficult-to-detect stability region at Neptune, called the Lagrangian L5 point. They used the discovery to estimate the asteroid population there and find that it is similar to the asteroid population at Neptune’s L4 point. The research is published in the August 12, 2010, online issue of Science Express.

Neptune ‘dead zones’ hold more rocks than asteroid belt – [newscientist.com]

An asteroid that is trapped in a ‘dead zone’ behind Neptune has been found for the first time. The finding suggests that the blue planet’s rock collection may outnumber objects in the main asteroid belt and may provide clues to the origin of comets.

Objects can become trapped in two gravitational dead zones around Neptune, where the forces of the sun and the planet balance out. In the last decade, astronomers have identified six asteroids – called Trojans – in the zone that moves in front of the planet along its orbit. But finding Trojans in the region trailing the planet has proved more difficult, because the faint light reflected off of objects there is washed out by brighter starlight from the plane of the Milky Way.

SEE ALSO:
The Rocks
1736 – Lagrange – bio

Comments are closed.