1) Position in the solar system: 5th planetary orbital position
2) Closest distance to the sun: Asteroid JG6—Perihelion: 48.28x10^5 km, 30x10^6 miles
3) Furthest distance from the sun: Asteroid Chiron—2.052x10^6 km, 1.275x10^6miles
4) Minimum distance to Earth: Asteroid Toutatis—1.480x10^6 km, 920x10^3 miles
5) Orbital inclination to ecliptic: Main belt--<4 degrees
6) Orbital eccentricity: Main belt—0.33
7) Diameter: Main belt—181.1x10^6km, 112.5x10^6 miles
8) Mass: Main belt—est. 22X10^6kg, 10x10^6lbs
9) Largest object in main belt: asteroid Ceres—974 km, 604.2 miles, in diameter (recently reclassified as a minor planet)
10) Number of known objects in main belt: 100,000; most are pebble size—16 have diameters of at least 240 km, 150 miles.
11) Types of asteroids: 3—
- Carbonaceous or C-type (make up 75% of asteroids—very dark);
- Silicaceous or S-type (appx. 17% of known asteroids—fairly bright composed of rocky material)
- Metallic or M-type(fairly bright, composed of iron)
12) Albedo:
1). There should be a planet where the asteroids roam – According to the Titius-Bode law, which states that planets form at specific distances from the sun and from one another, the position the asteroid belt holds is where a 5th planet should be. The orbit of Ceres is precisely where Titius-Bode predicts the missing planet! Why instead is there a cosmic junk yard? It was once thought that a planet had formed there and broken up or exploded. But now we’re reasonably certain that Jupiter’s massive gravitational pull prevented the accretion of the larger chunks of rock into a planet. This is borne out by the low mass of the entire remnants of the main belt. It is less than about a third the mass of the moon. The rest of the planet making material was blown away by the solar wind or pulled into Jupiter’s voracious gravity engine.
2) Not all asteroids reside in the main belt – There are two other groups of asteroids that are of interest to astronomers, and one of interest to all of us. The one we all share an interest in are the Near Earth Asteroids, or NEAs. These are asteroids whose orbits bring them out of the main belt and within 1.3 Astronomical Units (AU) of the sun. That puts them in striking distance of the Earth. Note that the asteroid Toutatis comes within less than a million miles of our planet. Others cross the Earth’s orbit regularly but at greater distances. To date, we have found 3400 NEAs. The largest is Ganymed—41 km, 25 miles in diameter. 1100 have diameters of more than a kilometer, 0.62 miles.
The other type of asteroid straying from the home field are the Trojans. These cluster at Jupiter’s LaGrange points—stable positions 60 degrees ahead and behind Jupiter in its orbit. Several hundred of these are known but thousands may exist.