Newly forming planetary systems are busy and messy. They contain disks of gas, ice, and dust that are broken into wide bands. The supply of dust is replenished by frequent collisions between “exocomets” – balls of ice and rock up to a few miles across. And the bands may be stirred by the back-and-forth shifting of newborn planets.

There’s a similar band in our own solar system – the Kuiper Belt. It begins beyond the edge of Neptune, the outermost major planet, and extends billions of miles from the Sun. Because the solar system has been around for billions of years, the belt is quiet – there are few collisions and little stirring.

Astronomers recently studied the bands in about 300 young star systems. They contain a lot of leftover debris from the birth of the planets. So collisions between larger bodies are much more frequent. The impacts blast out a lot of dust, feeding the bands.

In many systems, there’s more than one band. Gaps between them might have been cleared out by orbiting planets. And the bands come in different sizes.

Wider ones might have been “pumped up” as giant planets moved toward and away from the parent star. The gravity of those planets would have kicked many of the exocomets into different orbits, causing them to spread out.

The study didn’t see any planets. But the configurations of the bands suggest the planets are there – taking shape in the busy space around young stars.

Script by Damond Benningfield