<P> Most asteroids within the asteroid belt have orbital eccentricities of less than 0.4, and an inclination of less than 30 ° . The orbital distribution of the asteroids reaches a maximum at an eccentricity of around 0.07 and an inclination below 4 ° . Thus although a typical asteroid has a relatively circular orbit and lies near the plane of the ecliptic, some asteroid orbits can be highly eccentric or travel well outside the ecliptic plane . </P> <P> Sometimes, the term main belt is used to refer only to the more compact "core" region where the greatest concentration of bodies is found . This lies between the strong 4: 1 and 2: 1 Kirkwood gaps at 2.06 and 3.27 AU, and at orbital eccentricities less than roughly 0.33, along with orbital inclinations below about 20 ° . As of 2006, this "core" region contained 93% of all discovered and numbered minor planets within the Solar System . </P> <P> The semi-major axis of an asteroid is used to describe the dimensions of its orbit around the Sun, and its value determines the minor planet's orbital period . In 1866, Daniel Kirkwood announced the discovery of gaps in the distances of these bodies' orbits from the Sun . They were located at positions where their period of revolution about the Sun was an integer fraction of Jupiter's orbital period . Kirkwood proposed that the gravitational perturbations of the planet led to the removal of asteroids from these orbits . </P> <P> When the mean orbital period of an asteroid is an integer fraction of the orbital period of Jupiter, a mean - motion resonance with the gas giant is created that is sufficient to perturb an asteroid to new orbital elements . Asteroids that become located in the gap orbits (either primordially because of the migration of Jupiter's orbit, or due to prior perturbations or collisions) are gradually nudged into different, random orbits with a larger or smaller semi-major axis . </P>

How far away is the asteroid belt from the sun in km