The trick is, there's no need for weapons-grade 'wavium to make this work, indeed it becomes a little more 'theme' when a conventional (non-wavium) Superweapon is the driver.
For that matter, even a crude hydrogen bomb would work here, the idea was that it'd be _down_. We're not talking cracking the planet in half, but instead making it unsuitable for terraforming, and a nice dirty dirty bomb would be perfect for that.
Planetary Denial!Wire Geek - Burning the weak and trampling the dead since 1979Wire Geek - Burning the weak and trampling the dead since 1979
For that matter, even a crude hydrogen bomb would work here, the idea was that it'd be _down_. We're not talking cracking the planet in half, but instead making it unsuitable for terraforming, and a nice dirty dirty bomb would be perfect for that.
Planetary Denial!Wire Geek - Burning the weak and trampling the dead since 1979Wire Geek - Burning the weak and trampling the dead since 1979