(Left) The Hildas Triangle against a background of all known asteroids up to Jupiter's orbit. (Right) The positions of the Hildas against a background of their orbits.
The Hilda group is a group of asteroids that define the outer edge of the main asteroid belt, about 4 AU from the Sun. These asteroids have become locked into their present orbits by a gravitational resonance with Jupiter: a Hilda makes exactly three orbits of the Sun for every two that Jupiter makes.
The Hildas taken together constitute a dynamic triangular figure with slightly convex sides and trimmed apices in the triangular libration points of Jupiter—the "Hildas Triangle".
The prototype is 153 Hilda, discovered in 1875 by Johanna Palisa.
|Data for 153 Hilda|
|semimajor axis||3.975 AU|