Irys

Irys is an... unusual planet. Considered the stereotypical "Garden World", a world that has an ecosystem optimal for life, and that is quite common. But it's unusual in two ways: One being the fact that it has a .5% higher density than earth.

The other is that Irys' core is exposed as a result of a violent event that took out most of the southern hemisphere.

The remains are still in orbit around the planet, but the ecology on Irys is, surprisingly largely unaffected. The atmosphere around the planet is sustained by, at first, several large trees, often nicknamed "Yggdrasil" by the newer Norse settlers, but now it's resettled, several giant AtmosFacturers, which produces more of the same atmosphere at a steady rate.

Many are baffled at the crater's origin, though it doesn't stop scientists from researching it and settlers settling on it's asteroids.