The main asteroid belt
Between Mars and Jupiter, 3,000 rocks sit on this map at 2.1 to 3.3 AU from the Sun. They are generated rather than catalogued, and it matters that you know which: the real belt holds well over a million bodies larger than a kilometre, far more than any browser can draw, so these stand in for that population and follow its measured statistics without any one of them being a real observed asteroid.
What is actually modelled
- Semi-major axis
- Drawn from the observed belt density: three population humps at roughly 2.35, 2.7 and 3.13 AU, with the Kirkwood resonance gaps notched out.
- Size distribution
- A truncated power law with cumulative slope 2.3, the observed size-frequency distribution of the belt. Almost everything comes out small, which is correct.
- Eccentricity and inclination
- Rayleigh distributions, which is the shape a population built from many small gravitational kicks actually takes. Modes of 0.1 and 7 degrees.
- Determinism
- Each rock is a pure function of its index under a frozen seed, so the asteroid you buy today has the same orbit and the same sprite in ten years. That is a commercial requirement, not a detail.
- Names
- Numbered, never invented. A buyer can add their own name, which is shown here and nowhere else: it is not an IAU designation and it is not submitted to anybody.
The three populations
Inner belt 2.1 to 2.501 AU, 754 rocks on this map
The Flora and Vesta region, cut off at the 3:1 resonance with Jupiter at 2.501 AU, which is nearly empty.
Middle belt 2.501 to 2.825 AU, 1,141 rocks on this map
The densest part of the belt, ending at the 5:2 resonance at 2.825 AU.
Outer belt 2.825 to 3.3 AU, 1,105 rocks on this map
Runs out at the 2:1 resonance at 3.279 AU, which is the belt's outer edge.
The gaps are real. A body at 2.501 AU orbits three times for each of Jupiter's, gets the same tug at the same point every third lap, and is eventually pushed out. Zoom the map into the belt and the notches are visible.
The 40 largest
Sorted by radius. These are the ones big enough to read as individual objects at neighbourhood zoom.
Asteroid 179833.9 km across, 3.15 AU
Asteroid 31723.5 km across, 2.73 AU- Asteroid 97320.4 km across, 2.75 AU
Asteroid 85518.8 km across, 2.40 AU- Asteroid 288216.2 km across, 3.21 AU
- Asteroid 151312.8 km across, 2.38 AU
Asteroid 92811.9 km across, 3.21 AU- Asteroid 150811.3 km across, 2.70 AU
- Asteroid 296610.9 km across, 2.93 AU
- Asteroid 18369.6 km across, 3.14 AU
- Asteroid 1389.3 km across, 2.66 AU
- Asteroid 10049.2 km across, 2.78 AU
- Asteroid 6029.1 km across, 2.17 AU
- Asteroid 3508.8 km across, 2.39 AU
- Asteroid 688.7 km across, 3.22 AU
- Asteroid 5988.6 km across, 3.20 AU
- Asteroid 17758.6 km across, 2.31 AU
- Asteroid 27338.5 km across, 2.74 AU
- Asteroid 24438.3 km across, 2.81 AU
- Asteroid 25827.4 km across, 3.15 AU
- Asteroid 19837.3 km across, 2.92 AU
- Asteroid 22067.2 km across, 2.70 AU
- Asteroid 9967.2 km across, 3.20 AU
- Asteroid 9257.0 km across, 2.69 AU
- Asteroid 23176.4 km across, 2.99 AU
- Asteroid 28896.3 km across, 3.18 AU
- Asteroid 19306.0 km across, 2.78 AU
- Asteroid 15406.0 km across, 2.67 AU
- Asteroid 11206.0 km across, 2.90 AU
- Asteroid 12575.9 km across, 2.76 AU
- Asteroid 6145.8 km across, 2.55 AU
- Asteroid 8675.5 km across, 2.62 AU
- Asteroid 23985.5 km across, 2.67 AU
- Asteroid 24185.5 km across, 2.89 AU
- Asteroid 2095.3 km across, 2.71 AU
- Asteroid 22425.2 km across, 3.21 AU
- Asteroid 12975.2 km across, 2.36 AU
- Asteroid 15035.2 km across, 2.94 AU
- Asteroid 21905.2 km across, 2.44 AU
- Asteroid 12335.2 km across, 3.18 AU
Claiming one
$5 once, and it stays yours.
Procedurally generated. Name it whatever you like. Never sells out. The belt is the one tier that never sells out, which is why it is sold outright rather than leased. Pick one on the map.
Before you buy: a name here is a label on this map, not an astronomical designation, and permanence has exactly one disclosed exception, which is a link that stops resolving. Both are spelled out in the terms.